5EAT clunk 2-3

[scoobydoobie]

Hey I have noticed something weird lately. When manually shifting the car from 2-3 I hear and feel a clunk coming from the rear end. Anyone know what this is or what could be causing it? Differential maybe? Its a 5EAT and it only happens on the 2 to 3 upshift in "manumatic" mode, under moderate to hard acceleration. Thanks for any help.

[hammerhead]

if the rear diff. was shot you would feel the rear end hop on turns. bring the car in for service. you could have damaged the spider gears. but you wont know for sure until you get it checked

[scoobydoobie]

thanks, I might have to get it looked at. The weird thing is that it doesn't do it all the time, only in manumatic when accelerating hard in 2nd and shifting into thrid.

[Gmoe]

I've noticed something like this at times. I can't recreate the problem at will though. It seems to depend on rpm/temperature and happens most often when I shift at lower rpms. 3500 and above and manumatic shifts are the smoothest regardless of temp.

[dr. pepper]

My 2-3 shift is really sloppy and it clunks into gear unless I am giving it just the right amount of gas...

[SpawnGT]

My 2-3 shift is really sloppy and it clunks into gear unless I am giving it just the right amount of gas...

 

 

Ok since this thread was posted i realized i had an issue similair to this as well.

Dr. Peppe you have hit it on the nose. This is coming from someone with no engineering expertise or factual evidence or answers....i can recreate the problem exactly time over and over again exactly this way:

 

Press accelerator and right as you are about to shift(with manual or steering wheel controls) let go of the accelerator either wholly or slightly alil bit. I THINK the vale body has something to do with it, and it refers to a slight decrease in pressure that occurs when the accelerator is not being pressed at the time of the shift, but when their is the gas, the pressure that is made is enough to made a smooth shift between 2nd and third.

 

NO PROBLEM: ENOUGH GAS IS GIVEN AS SHIFTING IS OCCURING

PROBLEM: Release of gas between shifts and using manual mode.

[SeeeeeYa]

Ok since this thread was posted i realized i had an issue similair to this as well.

Dr. Peppe you have hit it on the nose. This is coming from someone with no engineering expertise or factual evidence or answers....i can recreate the problem exactly time over and over again exactly this way:

 

Press accelerator and right as you are about to shift(with manual or steering wheel controls) let go of the accelerator either wholly or slightly alil bit. I THINK the vale body has something to do with it, and it refers to a slight decrease in pressure that occurs when the accelerator is not being pressed at the time of the shift, but when their is the gas, the pressure that is made is enough to made a smooth shift between 2nd and third.

 

NO PROBLEM: ENOUGH GAS IS GIVEN AS SHIFTING IS OCCURING

PROBLEM: Release of gas between shifts and using manual mode.

 

When my 5EAT was on its way out I had a similar condition. In a futile attempt to save it until I got a VB upgrade I tried using a can of BG Additive from my dealer. Combined with a reset of the TCU, something only possible with equipment a professional has, AND that can of BG additive my transmission shifted smoothly again without the clunkiness.

 

Unfortunately, in a way, this didn't save me from having to get my transmission rebuilt. It did, however, reveal there are some maintenance methods for the 5EAT that might benefit the average user.

 

Therefore, it is my opinion that a BG flush of your automatic transmission, the addition of a container of BG additive, and a reset of the TCU would be good preventative insurance. Of course, this means that for a period afterward you must drive conservatively until the TCU relearns your driving inputs. BTW, normal methods we use to reset the ECU, like disconnecting the battery, will NOT reset the TCU, you must have it done with appropriate equipment.