Author Topic: Transmission Leak at multiple locations  (Read 347 times)

Offline Rtlane

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Transmission Leak at multiple locations
« on: March 07, 2019, 02:59:46 PM »
I recently purchased a 1982 C10 with a 305 and what looks like a th350 transmission. Be easy on me because Iím new to this. Itís been sitting for a couple months because I only use it if I need to haul something every once in a while right now. Iíve been noticing transmission fluid on the ground pretty much since I bought it. It has been winter, so I havenít had a good day to investigate.

I took photos of the areas where I noticed fluid on the transmission. At first I thought it was the pan, but now I noticed some on the rear seal and also on a hose coming from the transmission had fluid dripping from it. What is this hose? See the photos for reference.

Iím going to clean up the area soon so I can tell where its coming from a little better and then put it on ramps to get a better look.

It looks to me that there are various leak points that probably have been neglected by the previous owner. It doesnít seem plausible that all the places started leaking at the same time. So there are 3 potential places that are leaking. Iíll update the post whenever I investigate it further.









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« Last Edit: March 07, 2019, 03:04:12 PM by Rtlane »

Offline Ed4all10

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Re: Transmission Leak at multiple locations
« Reply #1 on: March 07, 2019, 07:25:59 PM »
Looks like your pan is leaking for sure. Pretty easy procedure to fix. Buy a new gasket based on your tranny model, I believe you will also need roughly 6 quarts of dexron ATF. Drop the pan, clean the mating surfaces, repaint the outside of the pan if you feel like it, and re install using a star torque pattern with the bolts. There are YouTube vids about it. Once that is sealed, clean everything very well, and check your levels using the dipstick while truck is running. Important to CLEAN EVERYTHING WELL after you change the pan gasket. Sometimes a leaky pan can cause fluid to blow all over the place and make it look  like your cooler lines are leaking. Either way, based on the pics, your pan is definitely leaking, so reseal your  pan first, And that should slow the leak down or stop it.

Also, while you have your pan off, how about putting in a new trans  filter? Again, not hard to do, just make sure the rubber gasket on the old filter comes out with it. There are threads on this site about changing transmission filters. Not a big deal At all, and this would be a perfect time to do it.

Plus, if the previous owner neglected the maintenance , fresh atf  and filter would be good for that trans. Make sure you buy Dexron compliant ATF. Read the back of the bottle, and either measure how much you drain out or buy at least 6 quarts of atf to refill.

This is a semi messy job, so make sure you have a large pan or something to drain the old atf into. Bring a lot of shop towels too. Good luck.




Edit: just searched YouTube. Search ďLukeís garage how to change your transmission fluid and gasket.Ē He takes you Step by step changing the pan and gasket on a square body.
« Last Edit: March 07, 2019, 07:40:38 PM by Ed4all10 »

Offline Irish_Alley

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Re: Transmission Leak at multiple locations
« Reply #2 on: March 07, 2019, 08:15:40 PM »
clean it up with brake cleaner and try to find the leak. that gasket is reusable. i would clean it all up and maybe even change the fluid while youre at it. proper tq for those bolts will fix most leaks. think its around 15 ft lbs. if after all that you still have leaks you need to trace them down. remember driving the truck will cause wind to blow the fluid all around. mostly down and to the rear but not forward, even if your hose is leaking it can cover the whole trans much like you have. so clean it all up tq the bolts and see where youre at then   
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Offline Rtlane

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Re: Transmission Leak at multiple locations
« Reply #3 on: March 07, 2019, 09:29:02 PM »
Looks like your pan is leaking for sure. Pretty easy procedure to fix. Buy a new gasket based on your tranny model, I believe you will also need roughly 6 quarts of dexron ATF. Drop the pan, clean the mating surfaces, repaint the outside of the pan if you feel like it, and re install using a star torque pattern with the bolts. There are YouTube vids about it. Once that is sealed, clean everything very well, and check your levels using the dipstick while truck is running. Important to CLEAN EVERYTHING WELL after you change the pan gasket. Sometimes a leaky pan can cause fluid to blow all over the place and make it look  like your cooler lines are leaking. Either way, based on the pics, your pan is definitely leaking, so reseal your  pan first, And that should slow the leak down or stop it.

Also, while you have your pan off, how about putting in a new trans  filter? Again, not hard to do, just make sure the rubber gasket on the old filter comes out with it. There are threads on this site about changing transmission filters. Not a big deal At all, and this would be a perfect time to do it.

Plus, if the previous owner neglected the maintenance , fresh atf  and filter would be good for that trans. Make sure you buy Dexron compliant ATF. Read the back of the bottle, and either measure how much you drain out or buy at least 6 quarts of atf to refill.

This is a semi messy job, so make sure you have a large pan or something to drain the old atf into. Bring a lot of shop towels too. Good luck.




Edit: just searched YouTube. Search ďLukeís garage how to change your transmission fluid and gasket.Ē He takes you Step by step changing the pan and gasket on a square body.
Thank your for the great info! Iím going to pickup a filter and gasket so I can go ahead and change it. Iíll clean everything up and see where iím at.


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Offline Rtlane

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Re: Transmission Leak at multiple locations
« Reply #4 on: March 07, 2019, 09:30:06 PM »
clean it up with brake cleaner and try to find the leak. that gasket is reusable. i would clean it all up and maybe even change the fluid while youre at it. proper tq for those bolts will fix most leaks. think its around 15 ft lbs. if after all that you still have leaks you need to trace them down. remember driving the truck will cause wind to blow the fluid all around. mostly down and to the rear but not forward, even if your hose is leaking it can cover the whole trans much like you have. so clean it all up tq the bolts and see where youre at then
Thank you Irish. Yeah I should probably pick me up a torque wrench. :)


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Offline Ed4all10

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Re: Transmission Leak at multiple locations
« Reply #5 on: March 07, 2019, 09:52:00 PM »
Good luck and keep us posted.
« Last Edit: March 07, 2019, 09:54:35 PM by Ed4all10 »

Offline Henry

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Re: Transmission Leak at multiple locations
« Reply #6 on: March 09, 2019, 12:14:45 PM »
Hi RtLane:
Those two rubber hoses coming off the pass side of your tranny are for the trans cooler. Original design is two metal pipes that ran up to your radiator and they threaded into the side tank of your radiator which had a integral trans cooler. You may not have this anymore...previous owner may have just mounted an external cooler on the front of the radiator. In any case, be sure to clean the hoses and all their connections near the tranny to make sure they are not also leaking. Does the drip on your trans tailshaft seal come all the way from the pan?...or does it just appear to be coming from the rear seal itself? If it is coming from the rear seal itself, this indicates the tranny is getting on in age and the seal is wearing out...after you get it all back together, if this seal leaks too much you may want to find out if it can be replaced without removing or disassembling the tranny.
Regards,
Henry

Offline MIKE S

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Re: Transmission Leak at multiple locations
« Reply #7 on: March 09, 2019, 07:39:20 PM »
If you decide to replace the rubber hoses on the trans cooler pipes make sure you get oil resistant hose. Do not use generic rubber hose from the parts store commonly called fuel or evap line. It will not hold up to oil and will soften and swell. Ask for bulk power steering return hose.

Offline Irish_Alley

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Re: Transmission Leak at multiple locations
« Reply #8 on: March 09, 2019, 08:07:05 PM »
and if the ends arn't flared now would be a good time to do it to help prevent the hoses from coming off the metal line
If you canít tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes