AWD Transmission: 'Transmission Service Required' warning when towing

[ms1975]

I have a 2006 XC90 D5 Geartronic 185. Every time I tow our caravan the 'Transmission Service Required' appears after around 5-10 minutes. This warning disappears after unhitching the caravan and when driving normally. The caravan laden weight is around 1500kg which is well within the stated towing limit.

I have seen other threads suggesting an ATF change for other members with this warning but it seems strange that this only appears when the transmission is under increased load i.e. towing. I wonder whether there is an issue with the auto box? The gear changes seem smooth when not towing but can occasionally be jolting when towing.

[harveys]

You need to get a oil cooler fitted,as the oil is getting to hot when towing.
The best thing to do is get the codes read if it says over temp then you know the problem.
When you are towing and the light comes on are you going up hill eg gearbox working hard,
Have you looked at the oil levels I think that might be a dealer only job,not sure if your car will have a dipstick on the gearbox.

[GJB]

Originally Posted by ms1975

I have a 2006 XC90 D5 Geartronic 185. Every time I tow our caravan the 'Transmission Service Required' appears after around 5-10 minutes. This warning disappears after unhitching the caravan and when driving normally. The caravan laden weight is around 1500kg which is well within the stated towing limit.

I have seen other threads suggesting an ATF change for other members with this warning but it seems strange that this only appears when the transmission is under increased load i.e. towing. I wonder whether there is an issue with the auto box? The gear changes seem smooth when not towing but can occasionally be jolting when towing.

As you are using for towing gearbox oil change recomended every 45.000 miles, had a 2004 XC90 due to not having change done cost me a new gearbox eventually.
Has it started to go into limp mode yet?

[ms1975]

Thanks for the replies. I will get the codes read and see what the issue was. The warning light comes on a random. Last time I was cruising at 55mph on a motorway at around 2000 revs.

I will check the ATF when I get home. I saw another thread with an image of a dipstick on the front of the gearbox so hopefully I will have the same. Didnt know abvout the 45k recommendation - might explain the warning as I dont know when the oil was last changed.

I have been told that Volvo can upgrade the software on the ECU to change the engine management when towing. Has anyone any experience of this or is an oil cooler a safer bet?

[harveys]

Just add the engine needs to running to check the level.
Best bet get codes read.

[ms1975]

Well I had the codes read by a transmission specialist and it turns out error code says the solenoid valve was stuck open. The specialist suggests that this could be caused by overheating which in turn was caused by the torque convertor not going into 'lock out' whilst towing as the car was not travelling fast enough.

To be fair to them they didnt advise replacing the transmission of ATF at this time as the car is acting normally when not towing.

I am not sure this has got me any further with the problem though and I can only guess the car will do this again when I next tow.

[GJB]

Originally Posted by ms1975

Well I had the codes read by a transmission specialist and it turns out error code says the solenoid valve was stuck open. The specialist suggests that this could be caused by overheating which in turn was caused by the torque convertor not going into 'lock out' whilst towing as the car was not travelling fast enough.

To be fair to them they didnt advise replacing the transmission of ATF at this time as the car is acting normally when not towing.

I am not sure this has got me any further with the problem though and I can only guess the car will do this again when I next tow.

An oil change is the answer.

[CarQuake]

Originally Posted by GJB

An oil change is the answer.

I tow Bailey Ranger 510 with a weight of 1500 kgs and the last 4 trips have had the same transmittion service required message flagged (goes away once the engine is left to coll for 30 minutes). I am not sure if this is just a monitor trigger on the engine management system flagging this when the temp gets above a certain level? - I also plan to have tramsission oil changed and will go from there - any idea how much this costs? and does anyone have any experience of this oil change fixing the problem?
Thanks!

[Philstar]

Originally Posted by CarQuake

I tow Bailey Ranger 510 with a weight of 1500 kgs and the last 4 trips have had the same transmittion service required message flagged (goes away once the engine is left to coll for 30 minutes). I am not sure if this is just a monitor trigger on the engine management system flagging this when the temp gets above a certain level? - I also plan to have tramsission oil changed and will go from there - any idea how much this costs? and does anyone have any experience of this oil change fixing the problem?
Thanks!

I am new to this forum but sadly not new to this problem.

I tow a Sterling Europa, just under 1500KG and whilst I now have an xc90, for one week now, last July went to devon with van in V70 2.4D Geartronic. Gearbox generally smooth when not towing. B'ham to M5 J27 fine, sadly stop start for most part due to traffic. Link road to Barnstaple put box under load and after 3rd hill car not changing gear, and gearbox service required showed up. Let box cool down and managed to get to site with 4 out of 5 gears. Once cooled down seem ok. Went to volvo dealer in Barnstaple, diag check showed solonoid sticiking. Also noted box over filled by a lot. Had box flushed and refilled with correct fluid as told they order in oil for individual gearbox as a number of options. The bill was £200 which included diag check. No problems going back home.

Back in devon this year and will be a little tense until link road completed. Will get XC90 checked before hols.

Cheers,
Philstar

[CarQuake]

Thanks for the response on this issue. I had the XC90 serviced again in late April and also had the ATF changed (for about £250 form the Volvo dealership in Coventry). The dealership said the fault log indicated a sticking solenoid and that anotehr XC90 which had towed a caravan in the Lake District had also recently had the same problem. All was good for the next trip to Oxford for May day bank holiday and I thought the issue was fixed; but yesterday on teh way back from Torquay (up some relatively steep inclines) the message returned "Transmission Service Required" along with the gear lock out at higher speeds (now I know what I am looking for). I pulled in after about 30 minutes to see if turning the engine off would re-set the gear lock out. After a stopping the engine the warning disappeared immeadiately! - no more lock out and we got home with no further problems. Whilst I now have a temporary fix I will need to look into the sticking solenoid - if that really is the problem! - I just can't believe if this is a common fault with the XC90 why I can't find more threads on this and recommended fixes.