2001 V70XC Transmission Engagement Clunk...and another Clunk

[DS1220]

I hear all of the weaknesses of the 2001 and 2002 transmissions... but my symptoms don't sound like others that I have read about. The engagements started acting up yesterday, but they are fine today. When I engaged the trans from park to drive, there was a heavy clunk, then another clunk about 4 seconds later... Like it was shifting while I was sitting still. Then, while I was doing these engagements and disengagements, the "service engine system" message popped up. When I drove the car 30 minutes later, then message disappeared, and it is back to engaging like normal today. Before this, I had felt sluggish starts, then what felt like either a shift or the rear brakes disengaging, then it would take off like normal. I was thinking that there may be a bad transmission speed sensor. Anyone have any experience with these symptoms??? Thanks!

[howardc64]

The service engine system message should have logged a time stamped code even if message is gone. Find someone with VIDA/DiCE tool to read that code to give you pointers on that issue.

Transmission problems on this car usually acts up when ATF is hot after say 20min of driving while drives perfectly fine when ATF is cold/warm. See if your intermittent engagement issues correlates with this.

A delay clunk when engaging from park usually happens in the following sequence.. P-N-D and the delayed clunk happens between N-D. This is the typical "backing out of garage" sequence. Thus this problem is called "garage shift". If yours is happening on P-D, then it isn't this particular issue.

Since you have an 01, ETM could be a culprit as well. VIDA/DiCE tool can run an ETM test to provide health info.

[JRL]

Doubt it's the ETM
The tranny is pretty far gone now

[DS1220]

Thanks for the feedback. I tried recovering the codes with a universal OBD2 code reader, and it did not have any stored codes. Would a VIDA/DiCE tool extract a stored code that a universal tool would not?

Also, I have not gotten the clunk condition to repeat after 20 minutes of driving. I take the long way home from work tomorrow. Maybe it will come back.

Just curious, why would fluid temp make a difference? I assume the theory is that a solenoid is sticking... are solenoid components expanding at different rates, or is it viscosity of the fluid making the difference? If viscosity, would a fluid change help?

THANKS!

[JRL]

Yes you can use VIDA-DICE
Fluid change almost always helps

[howardc64]

I tried recovering the codes with a universal OBD2 code reader, and it did not have any stored codes. Would a VIDA/DiCE tool extract a stored code that a universal tool would not?


Yes, generic OBD2 code reader only reads the standard codes. Lots of manufacturer specific codes can't be read.

Also, I have not gotten the clunk condition to repeat after 20 minutes of driving. I take the long way home from work tomorrow. Maybe it will come back.



Just curious, why would fluid temp make a difference? I assume the theory is that a solenoid is sticking... are solenoid components expanding at different rates, or is it viscosity of the fluid making the difference? If viscosity, would a fluid change help?


Hot ATF is thinner, I think the failure mode is some seals/channels are leaking when ATF is hot. And yes, per JRL's response, changing ATF almost always helps depending the condition of the current ATF.