G/box: 2WD: Auto Gearbox Issue

[BlueRubber]

My 2002 v70 has developed an issue where it makes a ‘clonk’ sound and there is a bit of a thud/ single large vibration from the gearbox.
This only seems to happen when exiting a roundabout and happens occasionally.
If I let off the throttle while existing 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 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.

Any ideas as to what the issue could be?

[ThomasG]

1: what oil did you use for drain and fill

2: are you sure you filled with right amount?

check fluid level

[BlueRubber]

1: I used the Volvo own brand fluid
2: I checked the fluid level using the full procedure, oil at 80c, engine running etc

[ThomasG]

interesting..

do you think Vida may be of help?

I think I`ll be going Pangbourne area on Monday, could stop and do readout.

in the meantime i`ll try to think up what may be happening with your car, but i think there are people here with more knowledge than me.

[BlueRubber]

Thanks for the kind offer but I have already scanned it with VIDA and there are no errors relating to the engine or gearbox.

I will double check the gearbox oil level again, but I am 99% sure it is correct.

My current theory is that after the gearbox oil change some crud has come loose and is interfering with the box.

[Georgeandkira]

Since it "only seems to happen when exiting a roundabout...occasionally" I'd look at the engine mounts.

Remember, the "top one" is a loosey goosey.

Remove the FR wheel and the 2 small nuts. Fold the fender liner away to reveal the mount by the crank pulley. It's the only way to get a good look at it.
They collapse with time.

The lower one in a Saab 9-5 I had (very similar design) caused big, deep thuds too. This is the one which connects the transmission to the body pan. It's "two ended" and has been called a "dog bone" from time to time.

No cheap replacement mounts allowed!

[BlueRubber]

That sounds like good advice, thank you.

How much play would you expect in the top mount and what is the best way to test it?

[Georgeandkira]

Does your top mount have a cylindrical insert or a squared one?

The cylinder style had torn its internal webs. 'Twas clearly gone.
It slid out and the $16 Volvo replacement slid in effortlessly.

The square one I replaced wasn't shot but I wanted a poly bushing. As many report, it does transmit a touch of vibration but nothing serious.

Test them by getting a friend to move the gear selector between D and R with the brakes firmly applied. You look at the amount of wobbling the engine does.
As stated, there's a bit of play built into the action. I believe this looseness invites wear.
EXACTLY how much wear is acceptable is something I do not know.
Inspect them all.
One which is gone will effect the others soon enough.

If you weren't an ocean away I'd send you my "old one". It happens not to be old as the PO had her original replaced.

The poly I tried in the cylindrical styled one was horrible.

[BlueRubber]

I am not sure what type of mount I have, I think a squared one, a picture is below.
https://my.pcloud.com/publink/show?c...FwlJBhtQDhXKBV

It’s difficult to see it on the actual car but in the photo it looks like the rubber of the mount is cracked, so I guess that means I need a new one.

And I will test the play in the mounts you the way you suggest today and report back.

Thanks!

[Georgeandkira]

That's a cylindrical one and looks ripped to me.

You can wash it and mask it off.
Mix up some "homemade polyurethane" and pour it in.
....or get a new insert at your friendly Volvo dealer.