'71 K5 TH350 Blowing Fluid on the Interstate. Help!

[badpeanut]

I was going to visit relatives for Easter and when I was about 20 miles from my destination I started to smell tranny fluid. I pulled over to find ATF dripping off the passenger's side of the tranny. I checked the fluid level which was good, where the kickdown cable and cooler lines meet the tranny it was AFT-free, the pan bolts were tight (not leaking here), but when I took off the dust cover it looked as though it was possibly leaking out the input seal since there was a very fine film of ATF on the back half of the torque converter? The K5 made it into town, but I used my entire quart of ATF in the last ten miles.

I was bucking a strong headwind the entire trip. I've never had any problems with this tranny before and recently serviced it. I didn't have time to do anything with it over Easter due to family commitments, so I'll probably have to trailer it back home when I can get some time off from work.

What would cause a TH350 to suddenly blow like this? Do I have to look forward to pulling the tranny to replace the input seal? Is there something easy I'm overlooking?

Thanks in advance,

Wes

[Fast68Chevy]

when you say right side, i am thinking dipstick tube O ring at the main case, inpout seals blow, it happens, a sure fire way to blow it though is by overfilling tranny, it doesnt take much to overfill and blow something

if its the seal for sure then yeah youll have to pull tranny at least far enough back away from engine to remove the torque converter to replace the seal, replacing sdeal is easycake, everything else thats involved isnt

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Randy- Lincoln, IL
randy@ccaonline.com
71 C-10, trying to assemble....sigh..
parting out 5.0LTPI '81 cutlass supreme brougham
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[RipMeyer]

Sounds like the front seal.

[cheyenne10]

Had this happen in the K20 Sub. a couple of yrs ago going 65 down the interstate. I assume your K5 is a 4x4. On mine the under side of the truck from the transfercase rearward was coated in fluid. Scared I was going to damage something expensive we had her towed home. Tow truck driver hit it on the head as did tranny shop, the seals in the transfercase adapter went bad causing ATF fluid to contaminate and to overfill the transfer case. Then it blew out a hole high up on transfercase. Had the transfercase dropped out and the adapter rebuilt with new seals to stop leak. The fluid on the exhaust caused a lot of smoke in the rearview mirror too, spooked me when I saw it.

[badpeanut]

It didn't look like it was leaking around the dipstick.

It looks like the leak is farther forward than the transfer case, but bad transfer case adapter seals are a possibility. I think I should definitely replace them when I have things out.

These ideas are good. Keep it coming!

[mrein3]

You may need a new drive sleeve too. The drive sleeve couples the tranny output to the transfer input and seals the oil seals they are talking about. Just like the harmonic dampner on the front of the engine, the drive sleeve can get grooved which would let tranny fluid by the new seals. They are still available from GM.