Transmission Slip? Throttle In High Gear At Low RPM
I also read a post where the transmission valve body needs to be replaced, but that was on older cars. I have an MY17 coupe.
My issue is not as extreme as this:
https://youtu.be/8g5nwiby5rI
I also read a post where the transmission valve body needs to be replaced, but that was on older cars. I have an MY17 coupe.
My issue is not as extreme as this:
https://youtu.be/8g5nwiby5rI
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It is a regular 7 speed auto transmission with the main change of putting a multi plate clutch pack in place of the fluid coupling.
NOT a dual clutch box.
The MB GT cars (GTS etc.) have a dual clutch gearbox.
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It is a regular 7 speed auto transmission with the main change of putting a multi plate clutch pack in place of the fluid coupling.
NOT a dual clutch box.
The MB GT cars (GTS etc.) have a dual clutch gearbox.
As for the issue at hand, I'd suspect that the valve body is having an issue and not the clutch packs going bad. It seems to be fine at lower speeds, but the clutch just doesn't want to or can't engage in the higher gears. It's more like its kicking into random neutral and not slipping. If the clutch packs were toast, you'd also expect similar behavior (albeit not as bad) at lower speed in lower gears as well.




I have noticed this behavior a few times, but not sure its slippage in a bad sense. I started noticing it long enough ago, and have done enough WOT pulls with no issues since, that I think the trans would have failed by now if it had actually been converter slipping. Fenerally once a torque converter starts slipping, it will get worse quickly and show up most under WOT.
Is it possible its the TCU programming is just making the torque converter flash up to ease stress on trans under high load?
Last edited by LessIsMore; Apr 1, 2020 at 05:48 PM.

My car has been recently modded and my tuner told me that my clutches would not need to be rebuilt until I was closer to 800 crank hp
However, he has seen some modded cars have to do it sooner with less HP but they were 1/4 mile cars doing hard launches over and over.
I run my car in 1/2 mile events and recently competed in an event with my new mods and did 8 runs with no tranny problems...but then again 1/2 mile doesn't require as hard of a launch. I usually either put the traction control in "Sport" or turn it OFF and pedal through tire slippage to get her rolling.
I also have not experienced any slippage like the OP but then again my car is recently tuned and modded.
BUT there must be a reason that Weistec offers a clutch rebuild for our trannies??? Just my 2 cents!
Last edited by W205-S; Apr 1, 2020 at 12:19 PM.

Attachment 424424
In my post I tried to convey that you should only have a possible problem with your tranny if your making big power...the OP said he was tuned but that doesn't tell me anything about how much power or TQ he is pushing or how the tune is delivered. So I was trying to make a general statement...guess I may have needed to word it differently???
If transmission valve body replacement is the fix, does anyone have the part #?



