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1999 Volvo gen 1 transmission problem


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PLEASE PAGE DOWN FOR UPDATE. I still need your help.

JB

 

 

 

I need some help. The Volvo dealer in Waco has had my truck since 11/03/16 and has still not fixed my transmission.

 

Problem: Truck shifts into reverse and immediately pops back into neutral and then back into reverse, yet never fully engages in reverse. Shifts fine in and out of all other gears. the problem started in Arizona when we were hooking up the rig. I was able to crawfish it back and hook up to rig. Drove to Tucson to go to Volvo dlr. Got up the next morning and truck worked fine for trip to dlr. Service writer said he thought it was an electrical issue, and that codes would be gone. They did not recommend working on it for that problem. I got back to the park, hooked up the next day and went on my way. No issues until one week later when I was going to hook up and truck once again would not stay in reverse. I was on a slight incline and was able to roll back and hook up. Drove to Waco, dropped the truck of on 11/03/16. They advised they would check it out the next day.

 

Diagnose and repair: I was advised mechanic had extensive conversations w/Eaton and all dios were run. Eaton's first recommendation was replace with a 10 speed manual. I advised that was not an option. Eaton and the mechanic decided the XY shifter was the problem. I asked the shop manager what he thought the problem was and he replied Eaton says it is the XY shifter. Pulled transmission, put it on the bench and said it worked exactly has it should. Pulled top cover and said transmission was clean and looked to be in great shape. Shop called Eaton again. Replaced XY shifter, stabbed transmission and problem is still there. Will not stay in reverse. They are once again talking to Eaton and leaning towards it being a shifter problem/wiring related. They are looking for shorts which is something I thought they would have done first. They also said they may need to replace the shifter. For better or worse it sounds like they are letting Eaton make all the repair calls.

 

I have two questions. One -- does anybody have any ideas on what is wrong with this transmission? and Two -- do you think I should have to pay ($5300) for a repair that did not fix the problem?

 

If this post does not make sense please ask me for clairification. All input is sincerely appreciated.

 

I will post any update.

 

Thanks

JB

 

 

THANKS FOR EVERYONE'S HELP.

 

UPDATE 11/23/16

 

I had an interesting phone call from the shop foreman last night. He called and said he might have led me astray. After reading the mechanic's hand-written notes (not in computer) he determined that the mechanic had called Eaton again and that Eaton said he needed to program the new XY shifter. While programing it, he found a shifter wiring harness that was bad (60 bucks) and that should fix it. I am not feeling warm and fuzzy about these folks. Now for whats wrong with that claim. He advised me much earlier on the the transmission bench tested fine prior to installation.

 

I think the wiring harness was the problem all along and that I got screwed. JMHO. I asked the shop foreman if they bench-tested the old XY and he said they had and it was bad. I just find it a little too convenient that the transmission tested fine on the bench, but would not work when installed and that they suddenly found another problem that would also cause it not to shift, and which was easy and cheap to repair. Why didn't they look into the easy-fix problem first?

 

Just received a call and they said the transmission is now working fine.

 

I still need help/advice on how to handle a payment discount with the shop. I really think the XY was not the problem. I am inclined to tell them I will pay for the XY shifter part, 1300.00 or so but not for the labor to pull the transmission.

 

Thanks

JB

 

they kind of have me by the short hairs as my rig is parked in their parking lot about 90 miles from our home.

 

Thanks

JB

 

Any and all ideas appreciated.

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Seems to me, since the dealer still has the truck, and the XY shifter didn't fix it, they should put the old one back on. And btw, it's a LOT easier to swap the shifter than to yank the tranny.

 

Now, I'm just an old farm boy, but I would try hooking up a by-pass wire and see if it really is in the shift control, or wiring harness.

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Lost our reverse gear in New Mexico. Dealer found the problem within 2 hours. 8 days later I had to beat their grubby little fingers off my truck to get it back. The problem (they said) was the transmission sensor and wiring harness. $1200 parts + $500 labor + $300 misc fees. 3 days later, in Cali, Truck wouldn't shift reliably - independent shop discovered that each and every battery connection was "falling off" loose. Wonder how that happened???

 

The older trucks were bad about cooking the wiring harness and/or several of the sensors. The new replacement harness relocates the wiring off the top of the transmission to a cooler location. Cooking the XY box? Not so much, but does happen.

 

Call the Volvo trouble line. Don't have the number handy, but check the resource guide. If that fails, PM me & I'll see if I can find it.

 

Paul

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I do not know how the contacts are made in the shifter, but that is where I would look. Make sure they are in good condition. Are there relays in the operation? Just throwing out ideas.

Ron has a logic point he has made here.

 

To take Ron's point one step farther you might consider that a MAJOR factor in vehicle electrical intermittent control problems often center around faulty grounding of various circuits. Items controlled with electronic devices often have NO tolerance for less than perfect grounding.

 

My life-long vehicle electrical-guru contends that faulty grounds have made him a multimillionaire and those millions are often made AFTER other shops have charged some Poor(er) truck owner a ton of money and NOT repaired the problem (faulty ground(s).

 

Intermittent control failure is the trademark of faulty grounds.

 

Drive on.....(stay properly...grounded)

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A lot of Eaton auto shift problems are to do with the wiring. At that age of truck, when the XY was replaced..for the extra couple of hundred bucks.. the wiring should be replaced as well. When my XY got weak, it wouldn't even go into reverse rather stalling the whole system and requiring a restart.. I personally keep the new parts.

 

The error codes when this even happens should be able to lead the mechanic back to the issue but my experience says otherwise.

 

What hasn't been mentioned here yet is the control box for the whole system.... that may be the issue..

 

Good luck and keep us posted..

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Thanks. I think the post is gone for good. I don't think it can be restored.

 

So, all that time typing and it won't do John any good. But maybe that's actually good for him :)

 

 

 

John, in summary, my recommendation was to consider replacing the entire transmission with a known good used or rebuilt one. My personal opinion is that it sounds like there is something mechanically wrong internal to the transmission. Eaton wouldn't recommend replacing an entire transmission for a manual 10 speed if it just needed an XY shifter. It sounds like something more is going on that they suspect. Something mechanical. And chasing that down could be expensive. Having the dealer do the rebuild may leave you with more risk as opposed to buying one somewhere else that has a warranty and then having the dealer install it. You may be able to get a break from them on the installation, but probably not. But you should be able to get a break from them on the parts.

 

It's possible that it is something with the ECU, which could be confirmed with an ammeter on the gear motor control wires, but that is pretty unlikely.

 

One item to confirm has been checked is the reverse sensor switch. This is a bit of a shot in the dark because I assume that they have already checked it since they took the top cover off, but you may want to ask.

 

Those are just my opinions, though. Based on my experience dealing with shift problems on my personal 2nd generation Eaton autoshift.

 

Best of luck. And if you want to discuss in more depth over the phone, I can do my best to relate my experiences and rationale.

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Long shot from the old farmer again........

 

I've been told that the gen 1 trannies were just an Eaton 10 spd with electric shift, gear box is the same. Is this true of the Gen 2? Could you remove the floor pan, swap the X=Y for a stick, and see if the problem goes away? Yeah, someone has to get their hands dirty, but it would be a lot cheaper than paying a "technician" to keep throwing parts at it.

 

My wife and I can have seats and floor out, and the top of the tranny exposed in just over an hour, removing the x-y takes all of 5 minutes. Sit on a 5 gallon bucket and try reverse.

 

Given that the dealer has cost you a bunch and not fixed it, he should give you this one.

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The power supply for the tranny ECM is located on the top of tranny and has power source from the batts over frame rail.

 

Has a fuse holder like Eng ECM feed. Ground to the batts. Check this. Easy change and cost new around $100.

 

Eaton recommend to replace when I had XY issues. Not reverse but other shifting issues and stuck in gear.

 

Also there is a switch on top rear of tranny called Rev Ball switch. This failed and caused no rev. It may cause a symptom like yours but just throwing it out there. Cost $35. 5 min change once access top of tranny.

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Gen 2 is also mechanically the same as a manual transmission. But there is more to it than just installing a shift lever. You have to connect the range valve and you would have to remove and rewire the transmission computer. Which will probably require some programming of the truck computer as well. Remember, the transmission computer can prevent the truck from starting and controls throttle to do float shifts.

 

For those that haven't had an XY shifter off before and had a chance to examine it, I'll describe a little bit about how it works. There is a shift "finger" (Eaton's term) that sticks down into the shift block of the transmission. It moves the shift blocks the same way that a manual shift lever would. The XY shifter (also called an "Electric shifter" by Eaton) has two motors. One is called the gear select motor and the other is the rail select motor. The gear shift motor simply moves the shift finger in three positions: forward, middle and backward. Forward and backward being with respect to the direction the truck is facing. Think of it like your manual shift lever. You push it forward for one gear, middle for neutral, and backward for a different gear.

 

The rail motor moves the finger in three positions: left, middle and right. Again, with respect to the direction the truck is facing. Just like with a manual shifter that you move left and right to position the shift lever for the right set of gears that you want to work with.

 

The motors are simple DC motors, nothing complicated or special about them. The way that the computer knows what position the shift finger is in is with two sensors. A gear select sensor and a rail select sensor. They match up with their corresponding gear/rail motor and tell the computer where the shift finger is. So when the computer wants to move one of the motors, it supplies power in the appropriate direction until the sensor tells it that the finger is in the correct location.

 

When you shut your truck off and hear all of that clicking from the transmission, that is the computer calibrating the XY shifter. It is moving the shift finger to all of the positions so that it can get a reading from the sensors and be certain of where the finger is so it moves it in the right direction when shifting.

 

Obviously, it can't shift into all of the gears when things are stationary. Inevitably one or two of the gears can't be shifted into because the teeth on the gears don't line up. Which is why it tries all of the gears to make sure it gets the full range of sensor readings. It only needs one set of shift blocks to allow it to shift the finger fully forward and fully backward to get that sensor's full range of motion readings.

 

This is relevant to John's situation because if the XY shifters (he's tried two, now) are not having any trouble keeping the truck in gears 2 and 4, then it is not the XY shifter itself that is the problem. If the XY shifter had a problem with the gear select motor, it would have the same problem regardless of where the rail select motor positioned the finger. The reverse, 2nd and 4th gears are all selected by moving the shift finger into the rearward position. Look at the shift pattern of an Eaton 10 speed manual transmission and you'll see how they are all in the same gear select position.

 

Given that the gear select motor is working properly, there are only two ways that the truck would pop out of reverse once it's engaged and working...either the transmission computer tells it to do so, or there is something mechanically wrong with the transmission itself.

 

If the computer is telling it to shift out of and into reverse, as John stated is happening, then either something is wrong with the computer, or the computer doesn't think the truck ever went into reverse. However, if the dash display shows a solid "R", then the computer thinks that it has successfully shifted into reverse.

 

I don't know when or how the reverse sensor switch comes into play for the transmission computer. Maybe it is used as a secondary confirmation that the truck is in reverse, in addition to activating the reverse lights. If that's the case, then maybe the computer is trying to shift out of and into reverse again because it doesn't think it made it into reverse in the first place. But if that were the case, then when it shifted back into reverse, it would be successful. But since it is not successful, that implies a mechanical problem.

 

If you shift into reverse and get a solid "R" on the display, and just sit there without letting the clutch out, if it stays in reverse and doesn't do anything, that would imply that nothing is wrong electrically. If the problem only occurs when you let the clutch out and start moving, that implies something mechanical.

 

This next test is probably beyond what John would do, since it is at the dealer now, but if you hook up an ammeter to the gear select motor control wires and watch it when you engage reverse, if there is no power applied when it pops out of reverse, then it is definitely NOT an electrical problem.

 

 

Again, as I and others have said, it would be good to confirm that the backup switch has been tested or replaced.

 

But, ultimately, it sounds like an internal mechanical problem that could only be properly diagnosed by disassembling the transmission and measuring all tolerances in all regards. Which is costly and would almost certainly be more expensive than buying a known good used or rebuilt transmission.

 

Just my opinions based on my personal experiences.

 

 

Please let us know how this turns out. As much detail as you are willing to provide would be really beneficial, at least to myself.

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I want to add that I am basing my above analysis on the following assumptions:

 

1) The truck will go into reverse, displaying a solid non-blinking "R", and allow you to beginning using reverse but then pops out of reverse while the clutch is released and you're moving

2) The truck then tries to shift back into reverse but either displays a blinking "R" or switches between "N" and "R repeatedly

3) The only way to get it to go into reverse again is to come to a complete stop, shift to neutral, push the clutch pedal to full stop (engaging clutch break), shift to reverse

 

 

If it never displays a solid "R" and never lets you use reverse at all, then that is a different scenario. But I think that the XY shifter can be ruled out since it has been replaced with no change in operation, and the wiring harness can almost certainly be ruled out because no other gears exhibit that behavior, which would definitely happen if it was related to the wiring harness. The reverse switch sensor is still an unknown to me as to how it affects operation, so that is worth checking.

 

So if my above assumptions are incorrect, then you are down to the transmission computer (ECU) or something internal to the transmission.

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Last post, I promise :)

 

Now that I have a little more time, I wanted to comment on the cost. I had done so in my original post, which was lost.

 

In my experience, most repair shops make the majority of their profit from the resale of parts. That is where they have the most room to negotiate. Their profit margin on labor tends to be very slim or non-existent. They cover their G&A costs for labor, but the rest usually goes to the technician. The only way that they can charge you less for labor is if they either take an actual real loss and pay the tech but don't charge you, or if the tech agrees to work for free or for a lower rate. Those are all unlikely to happen.

 

That's just something to keep in mind if you try to negotiate the price down. You may have better luck pushing them on the parts cost than on the labor cost.

 

You might be able to get them to R&R the transmission again at their expense since they did it once without successfully diagnosing the problem, but it would be an uphill battle. Their position is likely to be that they are being paid for time and materials to figure out an unknown problem, not being paid to provide a solution for a fixed price.

 

For reference, I have replaced my XY shifter twice, and each time it took under 2 hours including setup, clean-up, installing a driveshaft, removing and installing a weedburner exhaust pipe for access, moving slowly, double checking my work, replacing a wiring harness, and talking with "helpers". All from underneath and with the transmission in place. There was no need to remove the transmission or pull the floor up.

 

The Volvo dealer quoted me about 6 hours of labor for the same work.

 

As a result of my work, I have an extra newly remanufactured XY (electric) shifter for a Gen 2 Eaton Autoshift transmission. I also have a brand new wiring harness. If you, or anyone, wants these items, drop me a line and we can work something out.

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Shifted, lots of good information and thanks for sharing all that. When I first came to this site and learning more about HDT's, I was pretty set when it was time to buy an HDT, it would be a manual transmission truck just because of their simplicity and less chances of things going wrong, However, after reading many posts and learning more about them I now have a beter understaning that these automated manual trans aren't that much different, they just use sensors, selonoids, and electric motors to control what the human normally would be doing. From posts I've read, it seems kind of rare that there is actually a physcial problem with these automated transmissions since the computer does such a good job of shifting them unlike a normal manual that could very well be abused from a person not shifting it correctly. Normally when issues come up, they seem to be a sensor or something else that fails causing the normal process to break down and not work as expected. I guess if you learn to diagnose some of these yourself, or at least figure out the correct direction to look, that certainly helps keep the cost down when it comes to repairs. I enjoy learning more about this information so thanks again for sharing that.

 

 

BTW - if anyone would like photos of the shift blocks and the XY shifter's finger, let me know. I've collected a few and can post them if it would be helpful. I've also got the excerpts showing how the wiring harness connects.

 

Me personally, I'd love to see some pics of shift blocks and XF shifter's finger to better understand how it all works.

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Great info provided here.

 

On the Rev Ball switch, symptoms are flashing R not in rev. Fault code comes up. Serv light on.

 

Shutting truck off solved it for a while but eventually it hard fault.

 

The switch removed tested bad with meter.

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The following images are specific to a second generation Eaton Autoshift transmission, but presumably they are very similar to a first generation.

 

This is the wiring harness diagram from the service manual:

 

Eaton%20Wiring%20Harness.jpg?raw=1

 

 

 

Here's another view with a slightly different perspective:

Eaton%20Autoshift%20Wiring%20Harness%20D

 

 

And a third view:

Eaton%20Autoshift%20Wiring%20Harness%20D

 

 

 

And, finally, a PDF excerpt from the service manual detailing the removal and installation of the wiring harness:

 

https://www.dropbox.com/s/l5vl4d81vouomvh/Eaton%20Wiring%20Harness.pdf?raw=1

 

 

 

The full service manuals can be downloaded for free from Eaton, as well as full parts manuals.

 

 

 

Here are two photos of one of the XY shifters that I replaced. The "finger" is the metal tab that sticks out of the unit. In the photos, the unit is laying upside down. When mounted, the finger points straight down into the transmission. The gasket has been cut away to reveal the internals, but the gasket would normally cover all of the cavity except for the rectangle that the finger moves within.

 

Note the two permanently attached wires coming off of the two motors. These are the control wires for the gear and rail motors, which plug directly into the ECU:

 

DSCN2915-small.JPG?raw=1

 

 

In this next photo, note the broken plastic arm for the rail sensor in this photo. You can see it at the bottom right. A milky white plastic (normally white, but in this unit it is discolored from age and exposure to transmission fluid.

 

DSCN2914-small.JPG?raw=1

 

 

 

 

These next two photos are of the shift blocks as viewed from the top of the transmission. These are not my photos, just photos that I found online that show what they look like.

 

In this first photo, the blocks are all aligned in the neutral position. The shift finger would sit right in the middle. The rail motor moves the finger along the slot formed by the shift blocks, and the gear motor moves the finger against the shift blocks. In this photo, the front of the transmission/vehicle is to the left:

 

Shift%20Blocks%20-%2001.jpg?raw=1

 

 

 

In this second photo, you can see that one of the shift blocks has been moved out of position, which has engaged a gear. The shift finger would be in that slot and unable to select another gear until it moves that shift block to the neutral position. In this photo, the front of the transmission/vehicle is up, or away from the perspective of the camera. This is not the exact same transmission as what we've been talking about, but the shift blocks are nearly identical looking. In the below configuration, first gear is selected (a manual shift lever would be in the down and left position, pivoting at a point above the top of the transmission, placing its shift finger in the up and right position to fit into the shift block that is out of the neutral position in this photo).

 

Shift%20Blocks%20-%2002.jpg?raw=1

 

 

I hope that all of that makes sense.

 

 

In case it helps, here is the disassembly manual for an Eaton transmission. This should apply in general regardless of whether it's autoshift or manual, since this deals with the internals. This manual is a little harder to find, which is why I'm linking it here. I wouldn't rely on it for a full rebuild, but it can help a lot in understanding how it all fits together:

 

https://www.dropbox.com/s/cgvoazcu90vww4z/Autoshift%20Service%20Manual%20with%20Disassembly%20Steps%20-%20rr_trsm-0020.pdf?raw=1

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Bill, thanks. That tells me that it needs the reverse switch to confirm that reverse is engaged. A blinking gear means the computer is trying to select a gear but hasn't completed the shift. So it could be that the transmission computer moves it into reverse, receives no confirmation from the reverse switch, moves it out of reverse, tries again, etc. I think it is supposed to attempt a shift for 10 seconds before it fails, but I would have to look at the troubleshooting manual again to confirm that.

 

Is yours a 1st generation autoshift? The 2nd generation service manual doesn't show the reverse switch, but the first generation one does. I'm wondering if they did away with it on the 2nd generation.

 

 

Edited to add:

 

Found a "reverse light switch" in the gen 2 parts manual. Which seems to imply it only operates the light. I don't see any mention of it elsewhere.

 

Are there other gear position sensors on the gen 1 transmission? Maybe they used to use case mounted ball switches to detect the gear engagement instead of sensors built into the XY shifter?

 

 

Hoping that we hear from John with more details on the progress and confirmation of our assumptions or more specifics on the symptoms.

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From what I can tell by reading the service and troubleshooting manuals for the 1st generation of autoshift transmissions, the reverse ball switch is integral to the transmission computer's ability to confirm that the reverse gear is engaged. It even plugs into the main wiring harness, unlike on the 2nd generation.

 

The troubleshooting manual lists these as the possible causes for being unable to select reverse, inclusive of when the reverse ball switch failure code is stored:

 

-Failed reverse ball switch

-Damaged transmission wiring harness

-Gear select sensor in the electric (XY) shifter

-Mechanical failure in the electric (XY) shifter

-Worn Yoke

-Failed shift block

-Malfunctioning transmission ECU

 

 

Anyway, hopefully John gets back on here and gives us some more data. And hopefully they can get him sorted out quickly and without too much additional cost. But if they've already ruled out the reverse switch and wiring harness, it is likely the ECU or something mechanical, since they've already tried a brand new XY shifter. With my money being on mechanical (assuming that they properly tested and ruled out or replaced the switch and wiring).

 

 

Enough speculation. More data, please :)

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Just saw that you posted an update to your original post. Had no idea since it didn't update the thread as a new post :)

 

 

That sounds like very poor diagnostics. They pulled the transmission before testing the wiring harness? And they bench tested your XY shifter, found it to be bad, but that wasn't the problem? That doesn't make sense that it was bad but working fine other than reverse. It almost sounds like they were looking to pad the bill with labor (R&R the transmission), not properly troubleshoot the problem.

 

Do you have customization to your truck that affects access to the transmission that forced them to pull it for some reason? If not, I can't see any reason to pull the transmission to troubleshoot this problem.

 

As I said before, they have room to negotiate on parts, but rarely on labor. But I would push pretty hard in this case that pulling the transmission before testing the wiring harness was inappropriate. I would do my level best to insist that they remove that from the bill. Gently, of course, but firmly. I would also ask that they discount the XY shifter to their cost since throwing parts at a problem is not what you expect from a dealer, and ask that they give you the old XY shifter. There is a good chance that your old XY shifter will come back with damage if they are really trying to pull the wool over your eyes, but hopefully that's not the kind of thing you would get from a dealer.

 

If you are hitting a brick wall with the service manager, move on to the GM, and also reach out to Volvo directly. You may get nowhere, but you might get somewhere.

 

Here is the kicker, in my opinion. The Eaton service manual for a gen 1 autoshift says the procedure for installing the electric (XY) shifter is:

 

-Move shift finger to neutral

-Bolt shifter to transmission

-Reconnect wiring harness

-Reconnect gear and rail motors

-CALIBRATE the shifter

 

You do not "program" it. You CALIBRATE it. And this is how it is done, directly from the service manual:

 

a. Turn the ignition switch to ON and allow the transmission to power up.

b. Turn the ignition switch to OFF and wait two minutes.

 

That's it. That's the entire calibration procedure. It sounds to me like they are trying to cover for their mistake. You don't do anything with the shifter itself during calibration, so there is no way he would "discover" a bad "shifter wiring harness" while calibrating it. Unless he forgot to plug the XY shifter into the ECU and went back under there to discover that. But, as my earlier photos show, the XY shifter gear and rail motors come with their own hard wired connections, so there isn't a harness there to replace. The only "harness" in play is the main transmission wiring harness. Anyway, the calibration doesn't put you under the truck. You sit in the cab and turn the key on and then off, and then wait.

 

For what it's worth, the ECU wiring harness for a 1st gen autoshift looks to be about $400. So I'm wondering what they actually changed?

 

Do you have the model # for your transmission? That would help to confirm that I'm reading the right service manuals for your transmission. Or, you can look them up yourself on Eaton's site. You will want to do that before you call them back. Just to make sure that you have your facts straight on what is or is not entailed in replacing the XY shifter and what wiring harnesses are involved.

 

 

If it were me, and it definitely is one of the transmissions covered by the gen 1 service manual, I would push pretty hard on getting the R&R labor taken off. Troubleshooting is one thing, but paying for the tech to do unreasonable work and learn how to troubleshoot a transmission isn't right.

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