Hello All,

Need to ask a question around the L322 GM transmission. Currently I don't really have a problem , however I have noticed some changes. The gearbox was refurbed last year after the torque converter decided it had had enough. It has been fine since if always a little too eager to change down gear when there was the slightest hill. Recently however I have noticed that at 30mph / 1200-1500RPM and at 40MPH 1200-1500RPM if I very gently accelerate then I get a vibration as though the engine is under load ( similar to doing 30mph in 5gear in a manual car) The car does change down if I accelerate a little harder and otherwise I have no issues. My concern is that this seems like the Lock Up Clutch is starting to fail with the exception that I get the same behavior in manual mode and also in Sport mode ( although less noticable).

I read an entry in FullFatRR describing the LUC timing and although the symptoms seem to be similar the fact that it is affecting manual and sport mode seems it could be another issue.

Has anyone had a similar experience ?

regards

Might be worth mentioning that the reason the torque converter lock-up clutch fails in the 5L40-E transmission is due to lack of hydraulic pressure caused by wear (and therefore leakage) in the valve body. To keep costs down the repair shops tend to just replace the torque converter i.e. they treat the symptoms and not the cause. Unless the valve body has been replaced/Sonnaxed the replacement torque converter will inevitably fail too, just quicker this time. The repair shop relies on this being just outside of the warranty period.

Phil

HI Phil ,

I think you are spot on as I just gone past the warranty expiry of 12000 miles. A couple of questions, if I get an oil change done , will this buy me time ? Also do you have any recommendations for a garage to get this checked properly. I don't want to use the one that did the refurb. I am based in North London.

Vince

It sounds to me like you’ve gone past the point where a fluid change would make any difference but, as Dexron is relatively cheap, it might be worth doing just to check if there’s any metallic debris from the torque converter LUC in the old fluid. Hopefully you’ll have caught it before the friction material has worn through to the steel backing plate.



Sorry, but being ‘up north’ means I don’t really know of any good repair shops in your area but others on here may be able to help. I would recommend that you try to find a place that also replaces the worn spools/castings during the rebuild, or fits the Sonnax kits.





Phil

Hi Phil,


Many thanks for the detailed reply , excellent pictures.

I have to ask one question. Given your knowledge of gearboxes, do you work in this arena ?


Vince.

Just to finish this thread , I checked my warranty documentation from when I bought the car and it still has 6 months left so I will be speaking to them about it. However I can't find anyone who really advertises that they use the Sonnax repair kit when reconditioning the gearboxes. Does anyone know of a garage / specialist that definitely uses Sonnax kits ?

regards

Vince

vmpb said:

Just to finish this thread , I checked my warranty documentation from when I bought the car and it still has 6 months left so I will be speaking to them about it. However I can't find anyone who really advertises that they use the Sonnax repair kit when reconditioning the gearboxes. Does anyone know of a garage / specialist that definitely uses Sonnax kits ?

regards

Vince

Click to expand...

Seek advice, but it May be best not to mention to the garage you purchased the Rangie from or the warranty company that you have had work/repairs done to the 'box or they may rub their hands of it.
However.....why didn't you use the original warranty on the RR that you have to repair the box in the first instance?

Good luck with it either way

Hi ,

Sorry I must have omitted to say that the original recondition was done under warranty. However whilst the gearbox warranty has expired, I forgot the car was still inside warranty. The only other point is that the warranty company will want to use the same company to do the work, however this time I would like to get it done properly. From what I understand from Bremble and other info on-line , when the gearbox is reconditioned properly and the Sonnax valve repair kit is used , people seem to be very happy with the results. That being the case I would consider paying for the work to be done. I have spent the last 18months getting the car mechanically and electrically sound and the end was in sight ( rear suspension control arm bush pending), when the gearbox starts to play up again. I love the car but if I am only going to get 12k between gearbox failures then I will have to rethink.

regards

Just to close this thread. The company that did the work last year took the car back. They checked the valve block and all was OK but found that the lock up clutch was failing. Despite me being over the warranty mileage they changed the torque converter free of charge. All is good now.

regards

Result......there are some decent garages out there who will look into each individual case on its merit rather than blindly following a rule book!....