K5 Blazer Forums  
Home of the 1969-91 K5 Blazer/Jimmy including GM Trucks and Suburbans.  
Go Back   CK5 Forums > Technical Discussion > 73-91 K5/Suburban/Truck

Remove these ads.

Reply
 
Thread Tools Display Modes
Old 04-26-2007, 03:58 PM   #1
gothamist
Registered User
 
gothamist's Avatar
 
Join Date: Dec 2006
Location: Burbank, CA
Posts: 17

i Trader: (0 )

Question Replacing front seal on TH350?

My transmission has been leaking since I got this truck (December) and now the leak is getting a lot worse. It seems to be coming out of the front of the case. I have heard that the front seal on the TH350 is a common problem...so, a few noobish questions:

1) How hard is it to drop the tranny? Do I bring the transfer case (NP203) down along with it? I have a tranny jack I can use.

2) What all should I expect to replace? The transmission works fine, it just leaks. I am thinking the front pump seal and the brass bushing? (This is what the Auto Parts store guy told me.) Are these just plug and play parts or do I need to get anything pressed in?

3) Any pointers/suggestions are welcome.

Thanks.
gothamist is offline   Reply With Quote
Sponsored Links



Remove these ads.
Old 04-27-2007, 01:57 PM   #2
southernspeed
Registered User
 
southernspeed's Avatar
 
Join Date: Dec 2003
Location: Surrey, England
Posts: 4,320

i Trader: (0 )

GM of the month Winner
If you have a PROPER trans jack, a strong 'tilt-able' wide cradle, then take the t/case and tranny down together. I've done it on my own several times but it one HEAVY combo!
It's probebly (hopefully) just the seal. That's easy. The bushing I'm not familiar with.
Be careful man, if that combo starts to fall, you won't stop it! Strap it down good.
southernspeed is offline   Reply With Quote
Old 04-28-2007, 06:40 AM
Posted in reply to southernspeed's post starting "If you have a PROPER trans jack, a..."
  #3
MA87K5
Registered User
 
Join Date: Apr 2000
Location: Chicopee, Ma 01020
Posts: 558

i Trader: (0 )

I have rebuilt th350's before and haven't needed to replace the bushing unless it looked bad. The bushing has nothing to do with the seal. The seal can removed without removing the front pump from the tranny. If you can lower the tranny low enough to remove the convertor, then you can do it without lowering the x-fer case. Use something strong enough to use as a piviot point. Alot easier then dropping the tranny and x-fer case. I have done it so it can be done.
MA87K5 is offline   Reply With Quote
Old 05-03-2007, 09:36 AM
Posted in reply to MA87K5's post starting "I have rebuilt th350's before and..."
  #4
gothamist
Registered User
 
gothamist's Avatar
 
Join Date: Dec 2006
Location: Burbank, CA
Posts: 17

i Trader: (0 )

Thumbs up Thanks

Just wanted to say thanks for the information. This weekend I'll be diving into this so I'll see if I am smart enough to not need to drop the whole thing.
gothamist is offline   Reply With Quote
Old 05-08-2007, 10:35 PM
Posted in reply to gothamist's post "Thanks"
  #5
bigblock72
Supporting Member
Registered User
 
bigblock72's Avatar
 
Join Date: Oct 2005
Location: American Fork, Utah
Posts: 1,040

i Trader: (1 )

GM of the month Winner
While the trans is out remove the front pump and replace the o ring and gasket on the pump, they seem to leak more often than the converter seal. Removong the pump is fairly easy, remove trans, stand trans on end, remove pan and filter, remove bolts, thread in 3/8" bolts in tapped holes and hook slide hammer to bolts to remove pump. If you can't do it take it to someone who can. That's a lot of work to take a chance on, just bite the bullet and get all of the seals replaced, make sure you inspect the pump bushing once the converter seal is out. If the motor and trans are misaligned it'll burn one side of the bushing, generally very obvious.
__________________
71 Blazer with some stuff to make the 37s turn round and round.
http://coloradok5.com/forums/showthread.php?t=222300

72 K10: the garage queen

94 C3500 dually 454 w/whipple

01 Yukon XL 8.1 stock
bigblock72 is offline   Reply With Quote
Old 05-21-2007, 06:44 AM
Posted in reply to bigblock72's post starting "While the trans is out remove the front..."
  #6
roadnotca
Registered User
 
roadnotca's Avatar
 
Join Date: Sep 2005
Location: Redondo Beach, CA
Posts: 5,433

i Trader: (1 )

and be sure to use a hefty ring to drive the new seal, same size as the seal.
roadnotca is offline   Reply With Quote
Old 05-22-2007, 01:29 PM
Posted in reply to roadnotca's post starting "and be sure to use a hefty ring to..."
  #7
76zimmer
Supporting Member
Registered User
 
76zimmer's Avatar
 
Join Date: Nov 2005
Location: Kzoo, Mi
Posts: 19,661

i Trader: (7 )

GM of the month Winner
if the bushing is bad, it could cause a leak around the seal. If your going to pull the pump out, I would replace the bushing too. And you might as well pull out the direct drum and check the friction plates. How far you want to go?
__________________
N.E.D. ASDT MNGR club..Cofounder!!
My build thread: http://coloradok5.com/forums/showthread.php?t=261694
MyVette thread: http://coloradok5.com/forums/showthread.php?t=258437

RYOKEN: eesh, tonight, I'm contemplating 2 custom rear crossmembers and a $600 custom ss fuel tank.... what the F*CK is wrong with me?!?!?!!? :

CYBRFIRE: Nah, stainless is too brittle man. That would surely explode and kill you to death.
76zimmer is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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 -7. The time now is 02:03 AM.


Powered by vBulletin® Version 3.8.1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.