Transmission Slip Yoke leaking, wtf!

[Big D]

this question is about my 91 c3500 dually

I lifted it a while back and as soon as i had it sitting on jackstands, I noticed a leak behind the transmission, I figured it was the rear transmission output seal.

Anyways I finally got under her today to get a real good look and I find that its not leaking at the rear transmission seal, its leaking from a big bolt on the center of the slip yoke where the U-joint goes.

what causes the leak? is there a seal behind it? Is the bolt lose? can I just take the bolt out and put some Thread sealer on it?

 

[65nightmare]

this question is about my 91 c3500 dually

I lifted it a while back and as soon as i had it sitting on jackstands, I noticed a leak behind the transmission, I figured it was the rear transmission output seal.

Anyways I finally got under her today to get a real good look and I find that its not leaking at the rear transmission seal, its leaking from a big bolt on the center of the slip yoke where the U-joint goes.

what causes the leak? is there a seal behind it? Is the bolt lose? can I just take the bolt out and put some Thread sealer on it?

Is it just running down the slip yoke and dripping off of the bolt?

 

[Big D]

I thought the same thing when I took a quick glance.

I got a real good look at it, definately leaking through the bolt.

 

[65nightmare]

I thought the same thing when I took a quick glance.

I got a real good look at it, definately leaking through the bolt.

Hmmm i guess im not completely understanding where the bolt is mine is a 4x4 and the only bolts i have are u joint strap bolts.

 

[65nightmare]

Is the bolt going towards the transmission or through the shaft pointing up down or to the sides of the truck?

 

[Big D]

Not mine but this is basically the bolt im talking about.

You must be registered for see images attach

 

[Jrgunn5150]

Hmmm i guess im not completely understanding where the bolt is mine is a 4x4 and the only bolts i have are u joint strap bolts.

4x4's have slip yokes also, unless you did a SYE.

There is a oring inside the trans on the output that seals against the yoke. If it's failed one way or another, it will leak as you describe.

 

[65nightmare]

^ haha that

 

[65nightmare]

4x4's have slip yokes also, unless you did a SYE.

There is a oring inside the trans on the output that seals against the yoke. If it's failed one way or another, it will leak as you describe.

Yeah my reg cab long box has a slip yoke but my ext cab long box has slip yoke that is bolted tight.

 

[Texcuda]

That isn't slip yoke, it's a bolt on yoke. Common on turbo 400s. You said C3500 meaning it is a 2WD and being a one ton it probably has a turbo 400. Clean the threads and put some non-hardening sealer on them before reinstalling.