Auto Gearbox Clunk Issue

[BlueRubber]

My 2002 v70 auto has developed an issue where it makes a ‘clonk’ sound and there is a bit of a thud/ single large vibration from the gearbox and the revs rise.
This only seems to happen when exiting a roundabout and happens occasionally.
If I let off the throttle while exiting the roundabout then it doesn’t happen or is very minor, but if I maintain the same throttle position or accelerate off the roundabout this makes the fault most likely to appear.

The car has 139,000 miles, I did a drain and fill of the gearbox oil recently using genuine oil and since then the issue has appeared.
Before that the previous drain and fill was at 126,700, this was most likely the first gearbox oil change ever done to the car.
There are no errors in VIDA relating to the gearbox or engine.
The gearbox oil level is correct and the transmission torque mount and engine pad and top mount have been replaced and the front and rear engine mounts appear to be in OK condition.

Any ideas as to what the issue could be?

[SuperHerman]

First thing to do is to check your fluid level. Engine running, in park, warmed up, level surface, should read correctly. Optimal to have the perfect temperature but that is not always possible - so let it idle for 2-3 minutes and you should be close enough (assuming cold engine).

From there I would suspect you have a sticking solenoid as you have no codes. The early version of the valve body was redesigned to address the issue. Over time they gum up and cause problems. Volvo is all over the place on what valve body is actually installed on what car - at times it appears they find a lost pallet of them and stick them in cars that are not suppose to have the older valve body. Only way to know is to open it up and look to see if it is a no letter, an A, B or C. No letter is oldest, C is newest. I would guess you should have an A.

People have had good luck using SeaFoam TransTune and running it for sometime and then doing a drain and fill and then adding the rest of the can. Doesn't always work but liquid mechanic is easier than replacing the solenoids. Look up SeaFoam and transmission on the forum and you can read and decide.

[Katten]

Checking the fluid level must be done at 80°c, can be checked in VIDA.

Car must be leveled.

Move the gear selector from P through all gears with foot on the brake. Wait 3 seconds at each position of the gear selector. End at P again and wait approx 2 minutes and check level whit engine idleing. I usually check it multiple times right after I placed it in P, to make sure level is ok and it takes a minute to get hood open and fiddle out the dipstick .

Hope this helps. ATF fluid is very sensitive to temperature and will expand with heat so correct fluid temp to check level is required.



On the topic of your issue, can you check the RPM needle, does it increase and then drop down when you maintain the throttle through out the roundabout?

If so you have shift flare between 2nd and 3rd gear most likely .

[BlueRubber]

Update on this.

I checked the fluid level again and it was very low, which is strange as it was ok previously.

Cannot see any leaks but will monitor the fluid level for changes.

Thanks for the help everyone!

[vtl]

You may have a clogged filter. Check the level first thing in the morning, without starting the car. If the level is high, but drops severely after some driving time that would indicated a problem with filter.

[Katten]

You may have a clogged filter. Check the level first thing in the morning, without starting the car. If the level is high, but drops severely after some driving time that would indicated a problem with filter.

How does high level when sitting for some time indicate filter problem? I'm just trying to understand, not that I dont think you are right .

[vtl]

Dipstick measures ATF level in sump. When sump is almost dry because of clogged filter the level will be low. Let it sit for some time, the ATF will slowly drain to sump, the level recovers.

[Katten]

Dipstick measures ATF level in sump. When sump is almost dry because of clogged filter the level will be low. Let it sit for some time, the ATF will slowly drain to sump, the level recovers.

Oh okay, I understood it differently. My car when sitting for a few days have high level of fluid on the stick and when you drive it a bit it normalizes. Guess that is normal . Question is if it is ok that the level i high when the car has been sitting still for several days. Or if that indicates something. It is above the hot high mark.

[vtl]

You have to measure it with the engine running, otherwise it will be high.

[Katten]

Yea thanks, that was my thinking too!