The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1988 - 1998 GMT400 Chevy & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 01-26-2024, 04:17 PM   #1
Mr_Rich
Registered User
 
Mr_Rich's Avatar
 
Join Date: May 2006
Location: Yucaipa, Calif.
Posts: 795
K1500 700R4 rear trans seal

I've had my '89 K1500 on non-op for a few years since it got side-swiped while parked on the street. The damage wasn't too obvious at first until I noticed I kept losing trans fluid from the driveshaft area. Let me be clear that this leak is from the driveshaft after the transfer case and not before the transfer case.
I happened to view a TikTok video from Dave/ Dave's Auto Center and he talked about this same problem with a Ford truck.
When my truck was hit the left leaf spring was bent/ unsprung knocked the diff about 1" off. This caused some kind of damage on the driveshaft or output shaft of the trans. There is some kind of seal on the output shaft of the trans that is leaking into the transfer case where it then leaks out of the driveshaft seal.
I haven't been able to work on the truck due to weather and other time and financial factors. The time is coming due where I may have that chance and I need to do a bit of research now. Is the rear trans seal on a K-type 700R4 similar to the rear trans seal on a 2wd C-truck? I want to add that I'm talking about a seal on the end of the output shaft inside the output housing or transfer case support.
__________________
1989 K1500 Chev. EC
Original owner; some of the aftermarket parts I've installed are Borla headers, Hypertech chip, Edelbrock water pump, and a Stillen rear disc brake conversion kit.
2009 Hummer H3T 3.7L 5M (sold)
1997 K2500 Chev. EC 7.4L/ 4L80E (sold)
2018 Dodge Ram 2500 HD R/C

Last edited by Mr_Rich; 01-26-2024 at 04:25 PM. Reason: +
Mr_Rich is offline   Reply With Quote
Old 01-26-2024, 04:40 PM   #2
ChevyTech
Registered User
 
Join Date: May 2004
Location: Minnesota
Posts: 4,621
Re: K1500 700R4 rear trans seal

There is a seal in the front of the transfer case and it is a double lipped seal that seals fluid from moving in either direction. These seals can be very hard and brittle which seems unusual sense there is fluid on both sides of the seal. Usually they have several cracks in the seal material.

With a truck that old the T-case output seal could be hard too. Do to the truck having been hit the T-case output shaft may be bent.
__________________
For those of you that are wondering why you are not getting replies to your thread:
Did you give the model, year, engine, fuel system type, and transmission information?
If it is modified from what came stock from the factory, let us know that too.

Last edited by ChevyTech; 01-26-2024 at 04:46 PM. Reason: Add more
ChevyTech is offline   Reply With Quote
Old 01-27-2024, 03:43 AM   #3
Mr_Rich
Registered User
 
Mr_Rich's Avatar
 
Join Date: May 2006
Location: Yucaipa, Calif.
Posts: 795
Re: K1500 700R4 rear trans seal

Quote:
Originally Posted by ChevyTech View Post
There is a seal in the front of the transfer case and it is a double lipped seal that seals fluid from moving in either direction. These seals can be very hard and brittle which seems unusual sense there is fluid on both sides of the seal. Usually they have several cracks in the seal material.

With a truck that old the T-case output seal could be hard too. Do to the truck having been hit the T-case output shaft may be bent.
I rebuilt the drivetrain in the 2011-2012 time frame. I freshened up the seals and bearings at the time. I wouldn't expect the seals to be brittle. It didn't seem to me like trans fluid should get past the output shaft (of the trans) in the support area of the transfer case. I don't have a good area to work on it now. It's a dirt lot and I may have to create some kind of cement or brick pad for my work on it.
__________________
1989 K1500 Chev. EC
Original owner; some of the aftermarket parts I've installed are Borla headers, Hypertech chip, Edelbrock water pump, and a Stillen rear disc brake conversion kit.
2009 Hummer H3T 3.7L 5M (sold)
1997 K2500 Chev. EC 7.4L/ 4L80E (sold)
2018 Dodge Ram 2500 HD R/C
Mr_Rich is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:51 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2026, vBulletin Solutions Inc.
Copyright 1997-2025 67-72chevytrucks.com