TCM swap

abcdetech · Post by **abcdetech** » 04 May 2019, 07:57

Hi....I need a little help from transmission experts.

2006 Volvo XC70. 160K miles.
Transmission problem: transmission is "kicking" (like someone bangs you from behind) driving in town area, sometimes slipping. Problem started a year ago.
Things have been done: transmission flush, recalibration at dealership - that helped for 3-4 weeks but then problem started again.

The next step is TCM (transmission control module) replacement. Dealership quoted $2100. I've been told this process is a hot swap and no software upgrade required. So I purchased from swedish car experts a used part and they also confirmed this is a hot swap process. They have found a donor 06 Volvo S60 98K.
When part arrived I noticed that all numbers are matching but one.
I have two questions:
a. Is it Okay to swap TCM even if one number is not matching? Please compare attached images. Do you see a difference in numbers: T05353085 vs T05311535. Not sure what these numbers mean therefore double checking.
b. Is it really a hot swap process and no software upgrade required? I just pull out and insert a new module?

Thanks lot to everyone.

abcdetech · Post by **abcdetech** » 19 May 2019, 15:15

Since nobody replied I went ahead and swapped TCMs. Computer gave an error - Urgent Transmission Service Required.

I was told by techs it's a hot swap but looks like not always a case. I put my original TCM back and error got cleared. Everything seems is back normal.

Just for the record, if someone will have same question.

Post by **precopster** » 19 May 2019, 17:46

They CAN be a hot-swap if the same level of firmware is fitted to the car's system. If car went back to the dealer for a Canbus upgrade they will have different firmware versions. Both cars (donor and receiver) would have left the factory with the same level of firmware.

The hardware is the same. It's a 50:50 chance of getting a match.

Post by **abscate** » 19 May 2019, 20:12

You went from band aid to brain surgery with the TCM swap.

The success rate of non-pros foolingwith ECM And TCM I so about 0.001

Get To a shop that’s knows Aisin transmissions, preferably in Volvo application or do a good used trams swap if you don’t want to learn the internals.

Post by **vtl** » 20 May 2019, 09:30

abcdetech wrote: ↑04 May 2019, 07:57 Hi....I need a little help from transmission experts.

2006 Volvo XC70. 160K miles.
Transmission problem: transmission is "kicking" (like someone bangs you from behind) driving in town area, sometimes slipping. Problem started a year ago.
Things have been done: transmission flush, recalibration at dealership - that helped for 3-4 weeks but then problem started again.

TCM has nothing to do with that. It's either a bad valve body or Haldex is dying. Pull the DEM fuse, if that did not help then try to add a couple of oz of Lubegard HFM into transmission. HFM eases clutch packs engagement and takes down ATF temperature.

Did you install additional oil cooler and inline magnetic filter for your transmission? No? This is the first thing to do in Volvo.

abcdetech · Post by **abcdetech** » 20 May 2019, 18:03

Thank you vtl.
Just to add:
Transmission does a kicking after driving in town mode for 20 mins, I guess when temp inside transmission goes up
Mostly it happens when you press on brakes on red light or when you drive downhill. I guess one-to-neutrual shift or wise versa is not smooth.
My car currently has ABS antiskid service required ON. Dealer recommended to replace ABS control unit (I'm not touching it untill I figure out this issue with transmission which is more important). They don't think it's related to transmission.
After youtubing and googling about valve body and Hadlex - that makes sense and could be a cause of the issue.
My car was serviced at a Volvo dealership for many years, no, I do not see records they have performed magnetic filter replacement and oil cooler.
I decided to replace TCM because I saw the other day an error TCM failure, which never appeared again. And TCM replacement is on the list of transmission troubleshooting steps, therefore was my hope....

What I did today:
- Pulled the DEM fuse. Drove around the town for 20 minutes. Not enough, but the issue didn't appear. Shifting from one to neutral - I could hear it, but there weren't "kicking" issue. I liked it. It's acceptable, and I believe remaining hard shifting can be fixed by adding Lubegard HFM.

I'll drive for another day or two and definitely report back here. Modified subject of the thread because it's not a TCM only issue.

Thanks to everyone.

abcdetech · Post by **abcdetech** » 28 May 2019, 12:03

UPDATE....

After pulling the DEM fuse I have been driving testing the car for 4 days. Well..... it feels better however.....the problem appears again after driving for 1 hr on highway and getting back into town. Transmission "kicks" feels like someone hits you from the back.

My thoughts: "something" is failing, could be AWD or who knows what other modules, OR this problem comes up when temp in transmission goes up (if this problem appears after 1 hr of driving), right?

Next steps, I think, to:
- to add Lubegard HFM
- will do research and prepare for additional oil cooler and inline magnetic filter for transmission ( suggestions, comments are welcome)

thanks!

Post by **vtl** » 28 May 2019, 12:19

When does it "kick"? Describe what you feel. Also could you shift to manual mode immediately after next kick and tell us what gear it is in? And if it was doing up shift or down shift.

Oil cooler and a thicker* ATF will help. Not saying "fully cure", but will help.

[*] Most of JWS-3309 ATFs are thinner than 1161540. Volvo ATF has cSt@40 = 40, cSt@100=7.5, while Mobil or Toyota are like 34/7.2. And they don't have same level of friction modifier like Volvo does. HFM will help here as well.

abcdetech · Post by **abcdetech** » 28 May 2019, 12:56

It "kicks" on the stop signs, red lights, going downhill. I guess transmission needs to go from one to neutral; lower speed.
Feels like..hmmmm... put a newbie who never drove manual transmission and who doesn't release clutch pedal nicely, just hard shift, kick, hit to the transmission.....

I'll try experiments with manual mode, shifting, etc...and report back. I tried manual mode in winter time, loved, perhaps all problems started after that.....

Post by **vtl** » 28 May 2019, 13:12

2006 does not have the dreaded auto-neutral feature.

Stop and red lights is a down shift. Coasting downhill is up shift, it never does down shift. Can you track down what gear is it?

Any other shifting flaws besides that one problematic gear?