Transmission fluid leaking - side cover gasket?

katsura · Post by **katsura** » 17 Aug 2016, 02:03

Hey guys, my '03 XC70 is leaking transmission fluid, a few drops over night for a number of weeks.

I have traced it to the AW55-51's side cover, see photos attached. it seem to leak from the bottom of the cover seam, and also at the rear middle/top.

The reason this happened is I suspect because I added some transmission treatment and also overfilled it by about 200-300ml. This was done because I usually do a drain/ refill (just via the drain plug) for all 2nd hand cars I buy. It was done before I read upon so many tranny related issues on these cars, Had I know these issues I would have done a proper flush/refill and not mess with any treatment additives.

My questions are: is leaking from side cover gasket a common symptoms from overfill, maybe the gasket was weak from age and this just pushed it over?

Before I go take the cover off and re-seal the gasket, can I check if this overfill and slow leak may cause any other long term issues?

I do have a slight long engagement of 2-3 and 3-2, but I thought that's related to the B4 servo cover band? Is the '03 transmission (MFY Sept/02) still affected by the B4 cover issues? What's the serial number on the tranny that these problems went away?

Finally, can the side cover be removed in situ without dropping the subframe?

Thanks.

P.S> My Saab 9-5 (I was previously a Saab guy) also used AW55, and on the Saab gear slippage and hard change/ judder was treated by swapping the TCM control module with another one, because it was beleived the the TCM on these cars do go out after a decade or so), but on the Volvo it would seem most the isues are hardware related?

Post by **oragex** » 17 Aug 2016, 06:30

I have overfilled mine with more than 200ml and it didn't leak. Is the release valve on top of the transmission leaking?
If the valve body cover has to come out, the subframe needs lowered in front see the link in the video description

Post by **vtl** » 17 Aug 2016, 08:32

On pictures #1 and #2, what is this black plastic/rubber thing in between transmission and a subframe?

What is the history of this car? Did it have any transmission work or do you feel like it had?

katsura · Post by **katsura** » 17 Aug 2016, 17:15

Hey oragex, where is the location for the release valve? I had an inspection of the top of the transmission casing and didn't see any signs of fluid (however this is with all the piping and airbox in the way. I will certainly make a more thorough inspection. Id the release valve towards the front or rear of the casing?

vtl: I have no idea about the origin of the rubber (cushion?), it seems to be an OE piece, are they not supposed to be there? This is an Australian spec car with only 78300 miles on it and the previous owner was meticulous in servicing with the main dealer - it had 15 services in 13 years.

When I bought it I knew it had some issues, eg, the cracked fuel pump cover, and the DIM dies, I knew how to fix them and got the car for a good price.

After purchasing I did a stage 0 preparation as I do all my cars. which included all fluids. filters, timing belt and pulleys on this car.

I have to say before I did the fluids and timing I didn't notice any leaking fluid on my garage floor, and it was after I did the refill of the transmission fluid I noticed fresh red droplets on the bottom of the casing.

The fluid I used was Mobil 1 3309.

P.S> Is it me or is the transmission dip stick super hard to read? I followed instructions and I *feel* I'm reading it correctly (my dip stick had the bottom bit below the 'COLD' snapped off (while out of the car fortunately) and as for accurate reading for 'HOT' I never knew if it's just smear residue in the dipstick tube or real fluid level. With the engine hot and running, gear in P, the first time I pull it out it always show a lowish level, then if I re-insert it and pull it out for a reading after wiping it clean, it reads okay for HOT (between the marks)

Post by **oragex** » 17 Aug 2016, 18:17

Very hard to read since the level is very sensitive to the actual fluid temperature. If I remember well, a difference of 5C will cause 1cm level change. Which is a lot. Worst, the fluid continuously circulates through the radiator, so if driving on open road, it might never reach the specified level measurement temperature which is 80C. I'd measure it during summer days (no pb in Australia), after driving the car at least 1h inside the city, if possible with the a/c off because it turns the radiator fan on. It needs a 'thick' fluid smear on either side of the dip stick - hard to see with fresh fluid. I usually clean, put back and pull it again to read

Might well be leaking at the drain plug, if it catches just a small particle on the washer it will leak and it spreads over the transmission bottom

katsura · Post by **katsura** » 17 Aug 2016, 18:57

Thanks for the input orangex. I feel in this case it may not be the drain plug, as the streak of oil seem to come from the side and front rather than the back, and I also had 1 drop high up on the rear/ side of the valve case.

Post by **vtl** » 17 Aug 2016, 19:54

US market models don't have this "cushion", that's why I was surprised. I also don't remember seeing it on pictures posted at some EU Volvo forums I follow.

ATF is actually kept around 80C by a coolant. Transmission does not have its own cooler, it exchanges heat with coolant, which is +/- 80C most of time, and that's it.

If the car had valve body replaced, it's very easy to make a mistake and try removing return lane from valve body cover with only one wrench. Which tears the seal, and it starts leaking.

Make more pictures of valve body cover

Release valve is on top of transmission, near dipstick and gear selector switch.

Post by **cn90** » 23 Nov 2024, 15:30

The 2007 S60 Auto Trans with 120K miles has similar ATF leak as the O.P. (O.P.'s car is XC70, mine is S60).

ATF is at correct level.

The leak has a red color, so I think it is ATF
The weep hole between engine and trans is dry so I don't think it is RMS leak.

Has anyone figured out the source of the leak?
I doubt it is from the red gasket between the 2 halves of the Trans.

Post by **cn90** » 24 Nov 2024, 22:53

I downloaded a random photo from an eBay listing so ppl can see where the gaskets are located...

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: S60-ATF-Leak.jpg (57.39 KiB) Viewed 515 times

Post by **vtl** » 25 Nov 2024, 04:26

Are you sure it's not the driver side axle leaking?