Tranny Torque settings

[charlieatthedisco]

Hey guys. My tranny pan was leaking like crazy. The truck sits at an angle and the front of the tranny pan is angled down so all the fluid is towards the front of the pan. I replaced the pan and no leaks for over a week and then all of the sudden it is leaking again at the front of the pan. The torque settings in the manual say 120 lbs. I think that is nuts! the torque specs for the oil pan are only 20 but this is 120?! Can anyone tell me if this is accurate or not? My torque wrench doesnt even go up that high.

Thanks in adavance

[charlieatthedisco]

I forgot to mention that the truck is a 1978 350 silverado with the automatic tranny

[Jonboy]

Are you sure it's coming from the pan? When the truck sits, fluid drains out of the converter into the body of the trans. If it still has the original style o-ring seal on the trans dipstick, I would bet that is your leak. Also, a little bit of trans fluid will cover a lot of ground- it creeps everywhere.

120 ft-lb seems a little excessive for a torque spec. I would bet that is 120 in.-lb

[charlieatthedisco]

Originally Posted by Jonboy

Are you sure it's coming from the pan? When the truck sits, fluid drains out of the converter into the body of the trans. If it still has the original style o-ring seal on the trans dipstick, I would bet that is your leak. Also, a little bit of trans fluid will cover a lot of ground- it creeps everywhere.

120 ft-lb seems a little excessive for a torque spec. I would bet that is 120 in.-lb

Thanks for the reply, you are correct that it is 120 In lbs. Is the O-ring seal hard to replace? How can i find out forsure that this is where its leaking from?

Thanks for the help

[geezer#99]

Pull the inspection cover off and look for any fluid leaks up behind the convertor. It's not a cheap fix. Cheap 20 buck seal but the tranny needs to come out to replace it. Likely a 3 hour job. Close to 300 to fix.
Your leak could be coming from the shift selector shaft on the side of the tranny instead. Again a 5 buck seal but you need a 40 dollar seal puller to fix. And then it'll leak again in 2 weeks. Ultimate cure is have a tranny shop remove and polish the shaft and install a new seal along with a new filter, pan gasket and fluid. Just did mine both ways. Was 200 for the ultimate cure.

[Jonboy]

To replace the o-ring, the dipstick tube will have to come out. I would suggest getting the updated dipstick, tube, and boot seal. Should be under $30 at the dealership. To make sure that is the culprit, clean the area around the pan and dipstuck tube completely (brake cleaner will work well) and let it sit. Keep checking it daily and see if there is a leak.

[charlieatthedisco]

Thanks for the replies. I might just take it to a shop but I'm going to try the o-ring first

[geezer#99]

Just a sec charlie! Back up! Think about it! LOL!!
Before you go changing an oring that might not be leaking, clean off all the tranny fluid from the pan and up the sides of the tranny, pull the inspection cover off too, park the truck overnight facing downhill and then check the source of the leak. Could save you a bunch of frustration and money too!

[Jabes1]

Agree with Geezer. Clean it up and inspect... if its your trans pan:

If you have one of those reusable rubber gaskets that come with tranny filter kits now days, get rid of it... Ive had nothing but leaks from them. If you have a chrome pan (they warp) ... get rid of it and replace it with a cast aluminum pan which will not warp and gives a true surface for the gasket to compress against. The best gaskets I've ever used on the trans pans are the newer paper or old cork gaskets. Use Permatex High Tack gasket sealant on the pan, let it set up for a minute and place your gasket. You can put some on the mating surface that goes onto the trans but its not needed. Do not use silicone. Silicone is great for its intended purposes, but this isn't one of them.

[Jabes1]

Oh... and do not torque your pan bolts to 120 ft lbs. If you do that your going to have bigger problems like a pan that no longer bolts to your tranny LOL. You will pull the threads straight through the aluminum at that much torque and get to learn about heli-coils :/ You should be fine snugging the the bolts by hand, work from the center of the pan out when tightening. Good luck!

[68Timber]

The original torque specs were for a cork gasket that doesn't compress much. If the gasket you're using now is rubber you need to add another 10 or 15 lb/ft to properly compress the gasket and stop the leak.

[Jabes1]

Compressing rubber gaskets more causes them to split at the bolt holes over time or squeeze out when used with silicone. Been there done that...