E53 3.0 diesel no reverse, drives forward in neutral
 

Hello,

Recently I have bought an 2003 e53 3.0 diesel with transmission issues. It has GM 4L50E transmission.

Car seems to drive forward normally. Shifts up an down no problem but has no reverse and drives forward when neutral is selected. In between shift from park to reverse car tries to move forward, then stops abruptly. Behaves like if it was in park when throttle is applied in reverse. No transmission safe mode is shown on display.

Diagnostic shown 0 trouble codes in TCM but I am unable to connect to ECM. Also the check engine does not light up when I put key into second position.

I have removed the tansmission oilpan and checked the linkage and manual valve. Everything seemed normal no debree or metal inside, oil was not burned. After that I have removed the valve body and replaced it with one from used transmission that was slipping but was driving forward and reverse. Also replaced the range switch inside transmission. All of this made no change at all and car is behaving the same.

Also I have disassembled the original valvebody. All solenoids were functional no contamination inside. Valves OK. But 3 out of 4 springs in the acumulators were broken into pieces.

I would greatly appreciate any advice on whether should I remove transmission and look for internal problem or there is possibility of this problem being electrical.
There are signs of water corrosion on contacts of tcm but it seem old and car was supposed to drive fine just weeks ago.

Thank you all very much
Best regards Samuel

Is the gear position showing correctly on cluster (that information comes from EGS via CAN-bus)?

Yes, cluster and leds next to the gear lever are showing all gears correctly including S and manual shifting.

I think you’ll find that you actually have the GM 5L40-E transmission.

I agree that you should eliminate a possible electrical or electronic issue first, so I would recommend that you temporarily disconnect the 20-pin connector at the back of the transmission to deliberately put it into failsafe mode. Once in failsafe, Park, Reverse, Neutral and Drive (5th gear only) should all work under purely hydraulic/mechanical means without any electrical or electronic involvement. If you’re still having the same issues, then you have an internal problem with either the hydraulics or the mechanical running gear which will require the transmission to come out of the vehicle for investigation. Note that in failsafe, gear selection is harsher because there’s no line pressure modulation.

Phil

Thank you for response.
I have tried disconnecting gearbox but it will not start without that round connecor connected

Okay, so I have disconnected transmission on running engine. It went into protection mode but gearbox is behaving the same. Nothing in reverse and driving forward in neutral. So it is probably shot.

I am still unable to connect to ECM. It will detect it and show its details but I cannot read DTCs or look at live data. Always getting no response error.

Other modules like TCM or airbag are reading okay.
I am using Launch 431 scanner.

Any ideas on that?
Thanks

Sorry, my bad. I’m was thinking of the ZF 5-speed transmission which has an external inhibitor switch on a different loom. The GM switch is internal, so it is wired through the 20-pin plug.

Phil

Is the physical linkage the issue: I have a client who's e90 is just a little off: the car will be in N when you select R. You need to pick R+ (push a little farther) to get R. What you described above sounds very similar.

I have literally watched the spring loaded pin going right into its notches for each gear with oil pan removed. Linkage is working fine.

I have managed to connect scanner to ecm finally. Just had some settings wrong. Nothing there except glow plug.

I have tried all of the solenoids inside gearbox using scanner with my ear on the oilpan. All of them made audible click except "solenoid 2" I have tested all solenoids when I had valvebody outside gearbox so this can possibly be an problem either in the wiring or TCM. Can this cause my geabox not to go into reverse ?

I am unsure as I have tried it without electrical connection what so ever and it was doing completelly same thing.

I will probably slap used transmission in it. If it doesnt fix it I am breaking that hooptie for parts

Check out this link you don't have reverse.

https://www.bimmerfest.com/forums/sh...d.php?t=458451

If the manual valve is being correctly slid into its ‘Reverse’ position by the rooster comb then hydraulic pressure is being sent directly to the Reverse Clutch and the Low & Reverse Clutch to provide drive in reverse.

https://i260.photobucket.com/albums/...psgi6fyi2l.jpg

The only thing that can stand in the way of this is the Reverse Lockout Valve, which can be activated if the controller senses that the driver is trying to select Reverse while the vehicle is still moving forwards.

This is achieved by using the torque converter lock-up clutch solenoid (normally de-energised in Reverse) to activate the Lockout Valve to prevent hydraulic pressure being sent to the two clutches.

If the electrics are disconnected at the 20-pin connector then the TCC solenoid cannot be energised. Similarly, the three shift solenoids (1-2, 2-3 & 4-5) are not energised in Reverse. Hence, this can’t be an electrical or electronic issue.

Phil

P.S. To be able to start the engine with the 20-pin plug disconnected, a piece of bent wire would need to be fashioned that connected together pin sockets 2, 4, 11 & 16.

Thank you very much Phil for your response.

As I said I have tried unplugging the connector and car is not going anywhere in reverse. Also engine is not turning freely, it is being loaded similarly as if I was appliing throttle while standing on brake. Also I am certain that manual valve is working as intended.


Is there forward clutch that can possibly be seized causing the car to move in neutral and preventing it to reverse but at the same time not preventing transmission to work correctly in forward drive?

It is not possible to move car by pushing it when reverse is engaged and engine is running.

My thoughts, exactly. A seized forward clutch.

Phil

Hello, yesterday I have removed and disassembled the transmission. Diagnosis was 100% correct. Forward clutch was completelly burned. All of the material was gone. Friction discs have welded toghether causing transmission to lock up in reverse an drive forward in neutral. None of other friction discs are burned and are worn by 0.05mm or less.

Now I am wondering what could have caused forward clutch to burn up and friction weld itself. I really dont want just to replace forward clutch discs and have this happen again.

Any ideas on what should I verify before assembling the transmission regarding forward clutch?

Only other thing that I found wrong with the transmission were broken accumulator springs.
Thank you guys very much.

Have you been doing heavy towing work with the car? If it’s the first gear clutch that had seized it could be just heavy use or age.

Could be a few oil changes were missed Or just general bad luck and natural wear. The GM transmissions were always weaker than the ZF units, it’s one of the reasons they were replaced on later models.

Personally I’d check all the other clutch packs, friction and plates, and replace as nessicary.

Or if you have the money I’d get a full rebuild kit and change all the friction plates and all seals while your there. If you have the transmission apart then why not do a full rebuild and you know you will have a fully restored transmission in the car.

I’d empty and clean out as many oil galleries and the tourque converter as possible to remove any risk of material from The siezed clutch pack getting back into your newly built transmission!

Do the GM boxes have a cooler and thermostat? Some ZF boxes have a thermostat that can sometimes break and never let the trans come up to temp or worse not allow the trans to cool!

I’d check with one of the GM guys if there is a internal thermostat as you could ensure it’s working correctly as maybe the transmission overheated and burnt it’s way through the disks?

I have bought the car with damaged transmission. He told me that he drove it normally and all of the sudden he had no reverse gear.

I have checked other all other clutch packs and they dont need to be replaced. Wear is minimal.
Only the forward clutch is completelly obliterated. Maybe somebody neutral dropped it or whatever.

I will do my best trying to figure why it got burned, but I am not seeing any other damage, pressure was good etc.

Is

How many miles does the car have? Maybe the oil change was just missed or litterly never changed. Once ATF fluid gets contaminated or overheated it looses a lot of it’s required properties and 1,2 and may 3rd gear take the highest forces normally so it would make sense that 1st would be the first to burn itself up.

I would just ensure that the plates can move easily in the clutch pack assembly, check for any cracks, deformation or burrs. Anything that could mechanically stop or restrict the clutches from releasing. Other than that I’d ensure the mecatronics unit was clear of debris paying close attention to the 1/2 gallerys.

Also you mentioned that you couldn’t hear the solenoids all working? I’d ensure they are all functioning correctly before refitting? If that’s possible!

I would rebuild the pump for the trans. The regulator valve could be worn and is not maintaining the pressure needed to prevent the clutch pack from burning out.

Here's a video from one of my favorite Youtuber explaining this problem.

https://www.youtube.com/watch?v=_QVpTPrDKrg

You may find this useful. It’s the repair manual for the GM 5L40-e

https://at-manuals.com/manuals/gm-5l40e-5l50e/

Guys thank you really much for responses. I really appreciate it.
So I also I have bought same transmission from junkyard for 20€ thinking that something may come handy.

I have disassembled couple minutes it and discovered interesting thing. Drum of coast clutch is slightly narrower than one from my transmission and it allows 4 pairs of clutch plates for forward clutch to be used instead of 3. So I am definatelly using that part instead. Otherwise that junkard tranny is shot everything is worn badly I was hoping for good forward clutch plates but whatever. At least I have that one better part (and screws :) )

So I have ordered 4 pairs of forward clutches, teflon shaft seals and paper seals for valvebody.

My pump and regulating valve looks literally as good as new so I am not going to mess with that.

As soon as the components arrive I will put it togheter and let you know, hopefully it will work as good as new.

Also here is link for rebuild maual, maybe ti will be useful for somebody its much more rigorous than one from redraptor : https://shop.ukrtrans.biz/wp-content...logs/5L40E.pdf

Car has 350 000km but trans had to be overhauled already. There were signs of previous disassembly and torque converter was for sure repaired also (non OEM welds)
I will take a look on that thermostat thx for tip .

Ahh if the trans has been apart already and you think it was the wrong part that would defiantly explain why it was damaged then! If that 3 thick pack was too thick/too thin for what should be a 4 thick clutch pack that would explain the burning.

At a guess the clamping force wouldn’t have been strong enough allowing the clutches to slip, heat up and wear. Leading to seizure. Maybe the part is correct but they forgot to fit a clutch or plate?

No no, maybe I have explained it wrong. I am just learning english :)

My x5 had forward drum that was meant for 3 clutch pack pairs an 3 were correctly installed. But it burned to the point of metal melting toghether.

Junkyard one has slimmer coast clutch drum that allows one more forward clutch pack pair to be fitted while maintaining same coast clutches amount. It is stronger part ( maybe later reviesion ? )

I will use the one that holds more clutches, hopefully it will help

Ahhh okay that makes sense.

Well if it’s a revised part 100% put it in, car manufacturers won’t revise a part worse. And equally will only revise a part that needs fixing!

Are both models version ‘G’ or is one a ‘Z’?

Attachment 78270

Phil

Ahhhhh that’s why the gearbox is rubbish........ not only is it GM...... it’s also made in France!!



Only Joking the french make great cars..... And I drive a Range Rover with an engine even Buick thought was rubbish so what do I know lol

Update:

So after all that effort, repair sadly was not succesful.

I have been driving the car for past week or so after replacing burned forward clutch and something is still wrong.

I can drive it like if I stole it all day, works perfect shifts are fine.
But the problem happens if I drive uphill at about 30% throttle - about 90kmh

Once it attempts to shift into 5th something weird happens and transmission goes into limp mode. Thorwing code: 55 "gangueberwachung 5 " which is based on my research basically an incorrect gear ratio for 5th gear.

Never goes into limp mode or misbehaves if I only apply light throttle or beat on it hard so it stays in first 4 gears.

I have inspected all of the clutch discs before assembling the transmission and they were fine.

Replacement of forward clutch was fairly straight forward and everything made sense so we were able to diagnose it 100% correctly toghether.
But now I have honestly dont know what can cause this. Any ideas on this ?

Is the 5th clutch in fact slipping ? i do not understand this.

Thank you guys very much

None of the three shift solenoids are activated in 5th gear so it’s unlikely to be a solenoid issue. Are you getting engine braking in Manual 3rd gear? The reason I ask is that the overdrive clutch is applied in 5th gear (i.e. on the 4-5 upshift) but it is also engaged in Manual 3rd gear to provide overrun braking. The overdrive clutch is the one immediately behind ‘the-mother-of-all-circlips’ (you’ll know the circlip that I mean).

https://i260.photobucket.com/albums/...psprh1duvw.jpg

https://i260.photobucket.com/albums/..._overdrive.jpg

Phil

Thank you for response Phil. I have for sure inspected clutch discs of the clutch you mentioned. They were fine barely worn if at all. I sure know that circlip, even had to make huge pliers jus for it.
Today I have checked fluid again, I was able to get about 0.5L more inside (engine running, transmission in park ).
I almost thought that this cured the problem as I did about 60km without limp mode. Shifting completelly fine. Tried every possible driving mode including highway. It does shift into 5th and does stay in it with no slipping. I have verified it with diagnostic hooked and laptop next to me while looking what gear is engaged. I have shifted 4-5 and 5-4 manually many times and nothing happened.
But then at steady speed about 60km/h, flat surface limp mode again... Im pissed

And yes, I am getting engine braking in 3rd fine, everytime.

Im thinking of purchasing reconditioned velvebody to rule this out. But then again this fault was not in the error memory back when forward clutch was seized. So it is probably something that I have done.

I have disassembled the valvebody, cleanded it and assembled back toghether with new seals and accumulator springs. All of the balls are placed correctly for sure.

do you think that something like this would be a good idea or is it not worth the risk buying from china : https://www.ebay.com/itm/5L40E-Trans...Condition=1000

Also I have seen your autopsy of same thransmission on Range rover forum. Good job documenting I have to say :) I have plenty equipment, I can even machine my own oversize valves, bore the valvebody etc.. I just dont have any experience with automatic transmissions, this is my first time messing with it.

I am wondering if there could be possible leak here: (circled in the image)
causing sporadic 5th clutch slippage resulting in limp mode.
I have not replaced this rubber part.

I am willing to ramove and disassemble that piece of shit one more time even replace all of the clutches if that is necessary.. I can get exedy branded set of cluthches for about 280€ but generally I really dont like blindly replacing parts that still have life in them and those overdrive cutches really seemed fine to me.

If it’s like the ZF transmissions, these harden up and can cause hard shifting. But they could definitely cause slipping, as if the leak causes a PX drop it would reduce the clamping pressure. But this is a theory but a valid one. And cheap (on the ZF boxes)

For the price of them it would be worth changing them. Equally I’d change all of them
As a set as they are rubber parts so if ones shot all might be on there way out. If they are the same as the ZF boxes then they are easy to change, drop the mecatronics, and just some needle nose pliers and twist and pull.

Obviously again I’ve only been inside a ZF box but I think the component does the same in the GM one

Okay, so here is another update.

I have dropped the pan and pulled the valvebody off. I have checked that rubber seal that I have circled in the previous post and it is not it, Rubbber is soft, does not seem deformed in any way. I have also compared it with another one I had from the other transmission and they were identical.

So I have decided to try to slap on the valvebody that i havent messed with from the junkyard transmission that I have mentioned couple times earlier to see if something changes.

And something did indeed change. Now I am not only getting ganguberwachnung 5 , I am also getting ganguberwachnung 3 error.. and it shifts like complete garbage.. 4th gear comes with a bang and shift to 5th seems really delayed so not too much luck today.

Thats it Im buying new valvebody. I think that it is the root of my problems and also caused forward clutch to burn. Valves themselves are not worn but bores are quite loose.

Just wondered if you checked the overdrive clutch (4-5 shift) accumulator when you had the transmission apart?

Attachment 78346

Phil

Yes, I have checked the accumulators.
Only worry I have about accumulators are the springs. Manual that you have pulled drawing of the transmission from states that all 4 are identical. But this is obviously incorrect. It is possible that I have mixed them up. I am pretty sure that this can cause harsh shifting but can it cause limp mode and trouble codes?
Before i have disassebled transmission first time 3 out of 4 springs were broken into small pieces and it was still driving forward fine without jerking or limp mode.
Do you know of any documentation that states which spring goes into which accumulator please?

EDIT :
So i have found a document regarding springs. But it does not really match with my situation.
All of my springs were plain with no color marking.
Set that I am running now and before is from that junkyard transmission. But a havent kept them in order. They are all plain too and they have light differences in length (i thought that this is an deformation due to age and wear) I have put them in randomly both times. Could this really be the source of my problems? I just really can not see how this would cause those trouble codes.

Ok so I am happy to say that my gm transmission is fixed. I have been driving it for couple past weeks and no more limp mode.

Position of accumulator springs is apparently crucial for proper function of gearbox. If you get springs mixed up just like me, good rule of thumb that shortest spring goes into direct clutch accumulator this accumulator is also bigger diameter than other three in X5.

One from three remaining springs is much weaker and is made from thinner wire. This is also sometimes painted orenge and goes into 4-5 accumulator.

Last two springs might either be same or one of them can be longer by couple milimeters. If thats the case then the longer one goes into 1-2 shift accumulator.

Not putting the softest orange spring into 4-5 accumulator will cause 4-5 clutch slipping and damage. I have learned this the hard way but it that I have caught it in time as it seems to drive fine now 😀
Thx guys for help, car is working, repair cost me basically norhing and i have learned a lot about old automatic transmissiions.. Great success 😀

That's great news :thumbup:

Phil

Congratulations!!!!!!!! Great job.:thumbup::thumbup::thumbup::thumbup::thumbup: I applaud your perseverance.