TCM replace for rebuilt trans - 04 T6 AWD

wakenine · Post by **wakenine** » 26 Oct 2025, 18:11

Looking at a potential project - not my first Volvo, just got distracted by BMW for 15 years

) and

The XC in question (04 T6 AWD) has 110k miles on it, and had the trans rebuilt at 89k miles, but now the TCM went out (“an easy fix” I’m told). My questions are:

1. Does this sound legit? If the trans was rebuilt at 89k, would the TCM fail just ~20k miles later? My fear is that it’s not really the TCM but a poor rebuild on the trans.

And

2. If it is just the TCM, is it really just “an easy fix”?

Anyone else experience anything similar to this?

Thanks much in advance!

Post by **ggleavitt** » 26 Oct 2025, 19:50

I've never owned this powerplant but I did some searches on a number of variants of "4T65EV XC90 TCM replace" and there's like almost nothing on the subject. I've been a member of this site since 2005, I am well aware of the very common failure issues with the GM transmission but I've understood these to be transmission specific issues (transmission/coolant contamination notwithstanding) and not the software based controller that manages the function of the transmission. So intuitively I say No, no, and perhaps for #1.
For #2, the process to fix or replace (if you're not getting some guy to do it for you remotely) is here- https://xemodex.com/us/product-tag/volvo-tcm/ . Can also see here for a company that rebuilds the transmission for a living- https://tripleedgeperformance.com/4t65e ... ld-service , not sure if TCM is noted in the failures.

Last but not least, there's a thread here on MVS- https://www.matthewsvolvosite.com/xc90- ... ions-fail/

Edit- edit TripleEdge link.