I have a leak some where from my transmission, puddle in the garage. Not sure where it is coming from because I have fluid all over the place underneath. Is there any way to find out where it is coming from without taking it to a tranny shop. I thought I over filled it but the puddle keeps getting bigger and the fluid is low. Would a tranny place be able to figure out where it is without charging an arm and a leg? How many places could it leak from? The gasket is only about 6 months old with about 1000 miles on it. Thanks

 

Wipe all fluid off transmission. Let car sit overnight and see where most fluid drips off. Trans. can leak from torque converter, front seal, pan, dipstick o-ring, cooling lines, servo covers, tail shaft housing gasket, tail shaft housing seal. If no fluid shows up overnight drive car and check for source. Overfilling can cause fluid to be blown out of vent on top of case. If vent is plugged by dirt or grease it can blow out fill tube. Good luck. That is the place to start. mds...

 

If you didn't retorque the tranny sump pan after its first 30 days, chances are the pan gasket is leaking. Gaskets tend to take a set in their early days of use and the bolts lose torque. You need to get under the car and wipe down the pan to remove most of the oil from it. Then use a torque wrench to tighten all of the bolts to proper specification. If you find that they were pretty loose, that may be all you need to do. In any event, after you retorque the bolts, use paint thinner or mineral spirits to wipe all of the remaining oil off the pan and any other surfaces that have tranny oil (red color) on them. Then drive it a bit and check underneath for where any leakage is located. The normal locations are: the tranny oil sump gasket; the oil sump bolt holes; the rear output seal; the front pump seal and/or charging pump O.D. sealring [these will show up via leakage from the drain outlet hole at the bottom of the flywheel inspection cover]; the shift shaft seal; governer gasket/seal; modulator O-ring; oil filler tube O-ring; porosity leakage through the main housing casting (yes, they can open up years later). Hopefully, after you clean it all off and retorque the pan bolts, your leakage will disappear.

 

After checking pan gasket. A great trick:

Clean all parts with carb or brake cleaner. with rubberbands or string tie new white paper towels around all points listyed above. Let stand overnight. Then carfully remove papertowels and you will find the spot that leaked by seeing fluid on the towel. Worked great for me to find leak in spedo gear.

PS. I ended up having to put two seals in back to back.


Good luck

 

Front seal
Rear seal
Pan gasket
O-ring on modulator
O-ring on speedo gear
Cooling line fittings

I'm sure I've probably missed a couple of other places. Pan gasket would be my Number 1 suspect.

 

dont forget the cable selector shaft too. notorious for that.

 

Im not trying to hijack the thread, but I have been trying to chase down my trans leak also. This might be helpful to the OP also:

Does anyone make a gasket for the pan that is rubber with a metal strip in between like some valve cover gaskets? All I can find are the thin rubber ones and cork gaskets...I have tried both without any luck.

And how about those leak detector kits with the additive and uv light? Is this stuff harmful?

Sean

 

Got under the car yesterday and the gasket was leaking. I saw that the oil pan gasket was leaking also so I have both pans off now and going to change both gaskets. I am going to change the oil pump also while i am in there...it is 30 years old. I will give up dates later this weekend. I didn't see transmission oil leaking any where else. I hope this is the only spot. I have to get a torque wrench. I guess when ever you get to buy another tool, it makes laying on your back under the car fun.

 

75 vette,
I get my parts from advanced auto parts (10%military discount) and the only ones I ever get are the thin composite (rubber/cork) or cork. I never heard of ones with metal in them.

 

It is important to get both sealing surfaces FLAT and DRY before they will seal properly. If there are 'dimples' around the bolt holes, those bolts have been overtorqued and distorted the surface...classic cause for leakage. Find a piece of flat steel or a [machined] flat piece of hardwood to use as a backing plate on one side of the damaged area; then use a flat surfaced hammer to smooth that area out again. Once dimples and 'dips' are flattened, install quality gaskets dry and put all bolts in finger-tight. Torque the bolts gradually around the pattern, a little at a time. Tighten to 1/3 the spec on all bolts, then torque to 2/3 of spec, then tighten to spec. Let the pan sit for a few hours, then torque to spec again (they will 'relax'). Check them again after 30 days of operation. The best engine oil pan seal I've found is the one-piece [blue] Fel-pro gasket; you need a bit of black RTV for the corners adjacent to the end caps, but don't put it anywhere else. The tranny pan gasket that has worked best for me is the all-synthetic rubber gasket [black]...about 3/32" thick. Again, it must be DRY (gasket & surfaces) when you install it. You may also want to put a bolt-in drain plug into your tranny pan while you're at it...it's so much less messy to drain much of the oil out before you loosen the bolts!

 

Well I got the tranny gasket installed with no problem and oil pump. I had a bright idea of changing my oil pan to one of those fancy chrome ones and the *&^%$% won't line up. So tomorrow I will take it off and put the old one back on. I really don't like spending many hours on my back on a creeper under the car. I should be up and ready to go tomorrow.

 

I quit buying parts from Advance Auto parts just 2 days ago. Always bought everything from them that had a lifetime warranty. I took back some worn out brake pads on Thursday, along with my receipt from original purchase. They said they don't cover parts that wear out on the lifetime warranty, only parts that have a manufacturer's defect. Well, that was a surprise. Went to Autozone and they said their Lifetime warranty covers everything with no questions asked. That's why it is a lifetime warranty. Good-bye Advance Auto! Hello Autozone!

 

Well, I checked under my car today and there is a big pool of clean tranny fluid on the garage floor.....I give up, I have tried to change that gasket 8 times in the last 2 years and I just can't get it or it is leaking from somewhere else. I am taking it to the shop....To much time wasted on it. If for some reason they say my seals are bad or I need a new tranny (auto 350) or a tranny overhaul (?) what kind of price should I expect?

 

I see that your in VA Beach, if you don't mind crossing the tunnel there is a trans place in Hampton that i would highly recommend to anybody. Best Transmission 9908 Jefferson Ave, Newport News, VA‎ - (757) 599-4668‎. The people there are outstanding, and the prices are very reasonable. I had the tranny in my wife's 2004 Jeep Grand Cherokee completely rebuilt by them for about $1500 and it came with a 50K mile warranty from them, plus the used upgraded aftermarket parts whenever possible. A new tranny from the dealer would have been 4K. I even took my vette there when i found that my rear main seal was leaking, i called after work and they said bring it by and we'll look at it for free just to be sure. Drove it right over and sure enough, rear main seal, they had one in stock and dropped it in for me right there on the spot...$50 bucks. outstanding shop!

 

I am going to start it up this weekend. I am not sure if I could make it up there. I need to see how bad it is leaking. I will give them a call though.

 

rave3cO,
I tired the pan one more time and I finally got got the gasket right. No leaks. I did give Best transmission a call and they would have given me a free estimate. They sounded fair. I will keep them in mind. Thanks alot.

 

Glad to help! Another really outstanding shop over here is Barney's Auto on Salters Lane, family owned and operated. They were the ones who referred me to Best Transmission.

-Bill

 

How do you seal up this area? Gasket, bushing, or "o" rings??

 

Can you tell me which gasket you used? A rubberish one came with my filter kit, but I do not think it would seal as well as a high quality cork gasket, would it?

Mine is not leaking too bad- only after it sits for a couple of weeks, but I do need to change the fluid so the pan is coming off.

Thanks,
Dan

 

Dan,
The gasket I get is from advance. I am the wrong person to ask about transmission gaskets. The &*^%$# is leaking again. I have never seen a cork one, I would like to try one though to see if that works. The one they always give me is black in color and about an 1/8 inch thick. The longest time it didn't leak was about a month. Make sure you clean both surfaces real good with a solvent cleaner. I may have to take mine to the tranny place that rave told me about.