g60wall

I am having a audible thud from the driveline. Feels like the torque converter isn't disenagaing. When letting of from full throttle the car jerks as if the torque convert is locked. I suspected center support and flex disc, after changing them I still have the thud! It seems to have started after doing a full tranny flush when I get the car. I couldn't tell if it was there before because the motor mounts etc..... so I got a star. I try re-adapting the trans with star and I was able to make it marginally better. When turning the lock off clutch in star the car drives smooth as I expected it should. So I am thinking l, new valve body? The pan didn't have a spec of material in it!

cmpcpro

I can't tell you which part you need but I can tell you after owning two of the 5spd and two of the 7spd every single one of them has a little jolt feeling when accelerating when the converter locks. All my cars have been used with at least 45k or more miles so I can't tell when this starts but it's been there on all four.

g60wall

I currently own 4 big s-class I pretty well versed and I agree there is some normalcy but there is extremely more pronounced and when turning off the lock up clutch in star car is smooth as glass. The converter feels to stay engaged on decel, coming off full throttle there is a jolt! Coincidentally my S55 does this same thing ever since had the transmission replaced with a new unit. I feel it has to do with torque converter adaption and a under performing valve body. I order a new Mercedes valve body. I don't want to **** around with this. I'm on the fence on just replacing the transmission.

cmpcpro

I agree on trying the vb before replacing the whole trans! I would be curious to see how that helps. If it makes the converter feel a lot more seamless I would consider doing the same

g60wall

Well, car is pretty much non-driveable now. limp-mode is induced with any real throttle input in 1st and 2nd. I am figuring the Tune with no cats just toasted the 90k mile trans. After fitting the 5 bar regulator car pulled like complete monster. New valve body, will be here Thursday(big snow storm coming tonight) hoping that solves this issue, if not torque convertor will get thrown on. Not a spec of material in the pan, so i have a feeling it is just the valve body. Wish me luck

Heres a pull a few days before she pretty much let go. Also, just to add I'm not surprised that she let go, looking forward to replacing with new hardware!

ItalianJoe1

FWIW, I did the sonnax upgrade parts when I pulled my VB during the first trans service I did, one of the upgraded pieces is the TCC valve. Much better engagement on my unit now, although I still feel it's nowhere near 100%.



I had some, fairly severe, TCC and shifting issues in my car. I dropped the valve body and did a new conductor plate and trans service, and replaced the pistons Sonnax sells with the upgraded ones, one was the TCC apply piston. Between the fresh fluid and the reduced leakage through the VB, it feels like a new trans. I was fairly certain before the service that I was wasting my time and would end up needing a new converter and trans rebuild. I am still amazed at how much better it got for such a minimal investment.

Sonnax 68942-23K and 68942-05K were the two kits I ordered, cheapest deals I could find were vendors on Ebay

^^ copied from another thread

cmpcpro

Very nice thanks!

tusabes

Are you sure going into limp home mode is the transmission ? When my car went into limp home mode on hard acceleration it was a bad accelerator pedal

g60wall

Well I'm not 100%, but I'm pretty sure. Def not the pedal, I don't get any related code and it only happens when starting from a stop. Never even considered the pedal

ItalianJoe1

Does it still act up if you put the car in dyno mode?

cmpcpro

Hey Joe,

I just ordered those two Sonnax kits from eBay, is there anything else you think I should get or do while doing this? Thanks!

ItalianJoe1

I did those parts, a new conductor plate and a regular trans service. I'm gonna do fluid/filter again soon just because it's still kinda dark, not fresh and red. My unit was very clean inside though, not a lot of particles or anything strange scattered about, despite very brown fluid.

These transmissions respond well to good new fluid. I'd do the service and VB stuff and see what you get. I got intermittent speed sensor faults so I did the conductor plate (use OEM only), it's cheap enough insurance since you're in there. Also get the connector/plug that always leaks.

cmpcpro

Thanks! There is a seller on eBay selling all MB OEM conductor plate, filter, gasket, and plug for $170! I just ordered a kit.

ItalianJoe1

Nice, that's a fair price. The plate is right about $100, the other parts are fairly cheap so there's no reason not to get OEM in my opinion.

cmpcpro

Thanks it seems to be a pretty good deal, nobody has been able to match it so far.. also, which fluid is the best to run? Also how much do I need? Thanks again!

cmpcpro

Hey G60.. have you worked out your issues on your tranny?

ItalianJoe1

I used the OEM red fluid, since i'm at the dealer we always have it in stock.

You need about 5-6 quarts if you removed the valve body. You will need the workshop dipstick to set the level properly.

g60wall

I replaced with new valve body from Mercedes to the tune of $950. Car (transmission) feels brand new. Really glad the torque converter wasn't toast

g60wall

Took 3 and 1/2 quarts after removing the valve body. You got me all worried By the 5-6 quarts.

cmpcpro

Oh great.. I just spent $100 on fluid today at the dealer for 6 quarts..

I ordered those two Sonnax oversized fixes for the valve body but now that you bought a new one and it runs like brand new I want a new one lol.. wondering if I should try these first or if it's really like brand new maybe I should just do it right the first time..

g60wall

Really did make a huge difference. Why I did new valve body as opposed to sonnax kit was I just wanted to fix it once.

cmpcpro

Yeah I may just do the same thing.. that $950 was that retail? I have a wholesale account I get 25-30% off so that may help..

ItalianJoe1

I thought my trans was toast, so I figured for the ~$60 for the repair pieces, it was worth a try. My car drives much better now so I'm happy for the time being. When the trans lets go it will get beefed up for more power anyway.

cmpcpro

I've been looking into the Sonnax and it looks very nice I'm just wondering if I should try that or just do the valve body and be done with it. My cost on the valve body is about $700 and I can have it Wednesday.. still tying to decide. I like the Sonnax kit but the couple guys on YouTube who installed them said they didn't notice anything and that worries me..

cmpcpro

Did you have to do anything special for the valve body? Or did you just order it from the dealer with your vin and drop it in? Thanks!