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Please Help: AW71 ATF Leak!

Mylesofsmyles

A Member
Joined
Jan 18, 2010
Vehicle: 1992 Volvo 740 Turbo Wagon

Long story short: my AW71 is leaking ATF

Short story long: the car came fully apart in November to clean, reseal, service most everything. At that time the transmission received a new filter, input & output shaft seals and a new pan gasket. It was a Volvo gasket that appeared to be some form of neoprene or synthetic. I applied a little Toyota Transmission FIPG for good measure. All was fine, though the lockdown cable was sticky

Sourced Volvo lockdown cable, replaced it, though the Toyota FIPG rendered the gasket virtually not reusable. I cleaned it as best I could, applied fresh FIPG, then a leak started. Well two leaks, drain plug threads were damaged, and the pan gasket inevitably leaked.

Order new Volvo gasket (this time a cork style arrived!) and got a new pan and plug. Reinstalled and things were fine for a week or so (drove hundreds of miles). Yesterday it starts leaking. Seems to be along the left side and rear of pan.



Soooo…
I can order a new pan gasket, but I’m wondering if the OD solenoid may have a suspicious seal or something else I’m overlooking.

Any insight on the history of Volvo AW pan seals? Is the cork part of my problem?

Thanks!
 
I personally hate cork gaskets but others may have better luck.

If you can't verify where it's coming from I'd clean it and run it in the air under you can see it leak from somewhere specific.
There is an Oring at the base of the OD solenoid, did that get replaced as-well?
 
It's common for the pan bolts to be overtightened when there's a leak. The pan gets bent around each bolt hole and will not compress the gasket evenly. The pan needs to be straightened if this is the case.
 
It's common for the pan bolts to be overtightened when there's a leak. The pan gets bent around each bolt hole and will not compress the gasket evenly. The pan needs to be straightened if this is the case.
In your experience does gasket material effect what you recommend for torque specs?
 
You need to firstly know for sure where the leak is coming from.

What seems like a pan gasket leak can be other seals like the overdrive solenoid seal and the top of the overdrive solenoid itself.

As well as selector shaft seal, cooler line seals

The genuine rubber pan gasket needs no sealant. Neither do aftermarket cork gaskets for that matter
 
In your experience does gasket material effect what you recommend for torque specs?

Definitely. The cork gaskets will deform much easier than the paper gaskets.

A thin layer of oil resistant RTV can help seal the gasket
 
Definitely. The cork gaskets will deform much easier than the paper gaskets.

A thin layer of oil resistant RTV can help seal the gasket
I assume original is paper/neoprene/whatever and torque specs do not reflect the correct value for cork (in this case of course)?

I nearly religiously use the permatex aviation form-a-gasket paint on stuff for any paperish gasket and have yet to have any leak, but come across a lot of seeping cork on the stuff I work on.
 
I am going to have it in the air at a friend’s shop, in a couple days. I have a fairly high degree of confidence it’s the pan gasket, and I just tried “retightening” the bolts. Since it’s a used pan, maybe it’s guilty of having been over tightened prior?

From my untrained eye, I had a higher degree of confidence in the first, neoprene style gasket, versus the cork option which arrived this second time.

I know the gaskets don’t require FIPG by the book, but it can’t hurt. I’m pretty religious on using a thin layer as a just in case method.

Any advise on trueing a pan that’s been over torqued?

Seeping cork sounds logical to me also. Maybe the neoprene gasket is more forgiving?
 
For a possible easy fix you might try

https://www.amazon.com/dp/B07S21FYS9?ref=ppx_yo2ov_dt_b_product_details&th=1
which is the cheap version of

https://www.amazon.com/ATP-AT-205-Re-Seal-Stops-Bottle/dp/B000NVW1LM/ref=sr_1_3?crid=2XACC6OPLKGA2&keywords=at-205&qid=1678289935&s=automotive&sprefix=at-205%2Cautomotive%2C166&sr=1-3
I heard about this stuff on Scotty Kilmer's youtube videos. He swears by it.
I had a similar problem with my bell housing filling with oil(or so I thought) and after trying this stuff a couple of times I didn't notice any difference. Then one day I noticed my transmission fluid was low so I topped it off and added the cheap stopleak. Viola! it worked. It's now bone dry underneath my car.
 
For a possible easy fix you might try

https://www.amazon.com/dp/B07S21FYS9?ref=ppx_yo2ov_dt_b_product_details&th=1
which is the cheap version of

https://www.amazon.com/ATP-AT-205-Re-Seal-Stops-Bottle/dp/B000NVW1LM/ref=sr_1_3?crid=2XACC6OPLKGA2&keywords=at-205&qid=1678289935&s=automotive&sprefix=at-205%2Cautomotive%2C166&sr=1-3
I heard about this stuff on Scotty Kilmer's youtube videos. He swears by it.
I had a similar problem with my bell housing filling with oil(or so I thought) and after trying this stuff a couple of times I didn't notice any difference. Then one day I noticed my transmission fluid was low so I topped it off and added the cheap stopleak. Viola! it worked. It's now bone dry underneath my car.
Thanks but heck no. Pouring stop-leak in anything isn’t actually fixing the problem.
 
Just so you know, it's not a typical stop leak. It actually re-hydrates the seals so they can stop leaking. He explains it here:
These too:
 
Moving on from SUS band aid snake oil solutions (those are best reserved for FB and TikTok)

Car in the air and it’s leaking from pan gasket. I will order a new gasket, hopefully I get the neoprene one this time.

Welcoming your intelligent solutions to confirming trueness of pan surface and how to straighten if necessary.
 
I think a stiff 1' metal ruler, carpenter's square, etc would be sufficiently straight to show bends when held against the sealing surfaces. Long enough to run along the entire edge at once would be even better. It should lie flat - very small inconsistencies can be compensated for by the gasket, so I wouldn't worry if you can slide a sheet of paper under or see a speck of light between it and the pan / AW mating surfaces but much more than that and I'd be thinking about how to straighten.
 
I didn't get paid anything and it worked like a charm.
Still completely disinterested any corner cutting strategies based on somebody’s abundance of laziness and being cheap. Can we please get back on topic and discuss real strategies to actually fix a car?
 
As Ian said, the pan may have been deformed. No matter what material gasket you install you need to re-torque the pan bolts within a day or so. When that gasket heats up it will compress a bit more leaving the bolts loose. I wouldn't consider using either a cork or neoprene gasket without using a thin film of RTV on it. To straighten the pan you need a straight edge to check where it is bent and a hard, flat surface to straighten it on. You can do that a couple of different ways. The easiest is to put the pan down upside down on the flat surface and use a socket with and extension as a dolly and drive the surface around each bolt hole down so that the cone shape flattens out. It doesn't take a lot of force. Those pans are thin and the sheet metal wants to go back to its pre-deformed shape.
 
Awesome. I’ll get a fresh gasket ordered. Still feeling more confident in the neoprene versus cork.

I will try to straighten out pan.

Curious why you’d discourage the use of FIPG. How would that hurt anything?
 
I put at-205 in my saab gearbox a couple years ago. Still waiting for it to work. I'm sure it does something for rubber seals but I doubt it'll do much of anything to a paper/cork/etc gasket.
 
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