Transmission issues - 14 plate XC90

[whilewait]

Hi all,

Have a 14 plate XC90 (114k miles, 2.4l D5)with transmission gremlins - can someone advise on the likely cause(s) at all?

* Transmission flushed at 65k, and has behaved well until the last few weeks when I had noticed a little bit of variable revs in cruise control, and some very slight flaring for 4th/5th changes
* Towing a caravan recently up a hill, it appeared to get "stuck" at revs (like it's not locking the torque converter) at 3-3.3k rpm. Speed dropping on the hill until it finally changed gear.

Had gearbox flushed today - it was well due... Initially seemed to be shifting much better.

After some driving though, started to have issues as follows:
* Instances of high revs again when attempting to accelerate moderately (mostly in 3rd/4th, once in 2nd) with reluctance to shift up until about 3k rpm.
* Shifting down into 4th/3rd, despite little change in speed, again with high residual revs after shift
* Associated (but not every time) short coolant temperature rises from "normal" (half way on dial) up to 3/4 on dial. This appears to resolve quickly when the shifting works again. Coolant level is fine.
* Issue then resolves itself and shifting returns to fairly normal.
* When "stuck" I can't force a shift up (eg 4->5) using manual shifting.
* Fan comes on loudly when stopping car - this rarely comes on when driving usually, and then only in hot weather, and not early April in the UK...

There have been no warning or STOP messages appear as yet, and there were no related codes present when flushing transmission fluid (we have one that sometimes appears relating to oil level, but think this is spurious as dipstick level is normal it's currently not appearing and the dash is clear).


I'm guessing we might be looking at a transmission overhaul, but any ideas on potential symptoms? Many thanks!

[Harley Dave]

These guys know their stuff and sorted my gearbox issues a couple of years ago.

https://hortoncars.com/oxford-volvo-servicing/

Symptoms were different to yours though, juddering at 50ish, and I ended up with a new Torque Converter.

Been fine since.

Cheers

Dave

[whilewait]

Thanks - already have an auto box specialist in Carterton who we have used before (they will flush or rebuild/fix). More of a query at the moment around potential causes (but no juddering at all - in fact when it does shift, as would be expected, after a fluid change, it's quite smooth. Just getting it to shift all the time and the temperature increases on the coolant temp...!)

[GrahamBrown1]

Valve body could well be at fault, this contains the shift solenoids. The part is about £1000 and can be fitted without removal of the gearbox. Would be my next thoughts before removing for a full overhaul. You wouldn’t overhaul the box without replacing this anyhow so only a little bit labour cost if it didn’t cure the fault.

[Harley Dave]

On reflection, yes, the valve bodies do sound suspect.

Good Luck

Cheers

Dave

[Kev0607]

When you say “flushed” the trans fluid, what do you mean exactly? Is it done by a machine?

If so, I wouldn’t advise that on a higher mileage car. It increases the chances of dirt getting clogged in places it shouldn’t. Draining and filling the fluid is a safer option.

What fluid did they use? Its vitally important that the right spec fluid is used. Your car needs JWS3324 or AW-1 spec. Its not cheap fluid… quite expensive.

[Tannaton]

If it hasn’t been done on the last flush, try a gearbox (TCM) software update.

If that doesn’t help, the it’s surgery I’m afraid (valve body or gearbox refurb).

Finding a good gearbox specialist is essential as unlike manual gearboxes, autos usually need to be diagnosed whilst still running.