Allison 100 Trans Pan Leaking - Chevy and GMC Duramax Diesel Forum
06-07 LBZ & LLY Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission, Etc.

 
LinkBack Thread Tools Display Modes
post #1 of 7 (permalink) Old 06-29-2019, 09:20 AM Thread Starter
 
Join Date: Jun 2018
Posts: 6
Allison 100 Trans Pan Leaking

Anyone ever have a problem with the trans pan gasket leaking? Ive changed the gasket 3 times and it still leak in the rear of the pan. All the bolts are torqued to spec (18 ft lbs). Any ideas what options are available to stop it from leaking?
navman28 is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old 06-29-2019, 09:28 AM
Junior Member
 
Join Date: May 2018
Location: we live in a high mountain valley in the hi country of northern arizona
Posts: 241
how positive are you that the leakage is at the pan gasket? Oil (especially tranny oil) is sneaky. Can fool you. In both my aviation and automotive work, I have found the dye kits to be the fastest way to confirm exactly WHERE an oil leak originates. There are several on the market - they sell you a pair of special goggles, and little bottles of dye you dump into whatever is leaking oil. And a special flash-light. In a dark area, the area where the leak is actually coming from just literally JUMPS out at you.
6686L is offline  
post #3 of 7 (permalink) Old 06-29-2019, 12:49 PM
DuramaxForum Veteran
 
Join Date: Aug 2009
Location: Berryton, KS
Posts: 1,233
If it is truly the trans gasket that is leaking, a new gasket is called for under the circumstances. Clean the pan and transmission rails (where the gasket touches) thoroughly.

Ron Nielson
2008 Silverado LT, CCLB, Edge Insight CTS
2009 Arctic Fox 29-5T, Silver Fox Edition, Onan 3600 LPG generator
Ron Nielson is offline  
Sponsored Links
Advertisement
 
post #4 of 7 (permalink) Old 06-29-2019, 03:00 PM
DuramaxForum Veteran
 
Armus's Avatar
 
Join Date: Jun 2012
Location: Tar Sands
Posts: 1,640
Check for nicks / deep scratches on the mating surfaces contacted by the gasket.

DPF/SCR technology summarized in three words: It doesn't work.
Armus is offline  
post #5 of 7 (permalink) Old 06-29-2019, 04:50 PM
Senior Member
 
Join Date: Jun 2017
Location: Danbury, TX
Posts: 691
Back in the old days before drain plugs, we would take a pair of hammers and check to see that the bolt holes were flat to ensure proper seating of the gaskets.

On the trans leaking from the rear, I think there was a thread a while back where the connector plug or selector seal was leaking and running down the gasket and making itself known by the fluid found at the rear of the pan. Might start checking the sides of the trans to see if there is anything that looks "wet or damp".

2004.5 Silver Birch Metallic GMC K2500HD
18 Denali CCSB 2500 4WD Mineral Metallic with Cocoa/Dark Sand Interior
jlawles2 is offline  
post #6 of 7 (permalink) Old 06-29-2019, 11:08 PM
DuramaxForum Guru
 
1TRIKHD's Avatar
 
Join Date: Jul 2012
Location: Where Loggers do it better in the Woods. PNW Son!
Posts: 16,989
Quote:
Originally Posted by jlawles2 View Post
Back in the old days before drain plugs, we would take a pair of hammers and check to see that the bolt holes were flat to ensure proper seating of the gaskets.



On the trans leaking from the rear, I think there was a thread a while back where the connector plug or selector seal was leaking and running down the gasket and making itself known by the fluid found at the rear of the pan. Might start checking the sides of the trans to see if there is anything that looks "wet or damp".
I agree with this. On my lbz I thought I had a gasket leak at the rear of my pan. End up being the main harness, where trans fluid would leak through where the wires came from the inside of the pan to the outside and spread around where the pan gasket was. Replaced that harness and all was good.

Sent from my VS988 using Tapatalk

2006 Victory Red CCLB LT3 LBZ
Tuned by Blake Crenshaw
SDP Fully Built Trans w/ Billet Goerend G Converter
S472 SX-E.87/1.0ar sitting on a Wagler street intake W/ a twisted pedestal
Stock Sticks
Special thanks to Scott with Screaming Diesel Performance
Blake with Unleashed Duramax tuning
1TRIKHD is offline  
post #7 of 7 (permalink) Old 07-21-2019, 08:04 AM Thread Starter
 
Join Date: Jun 2018
Posts: 6
Turns out it was the shift shaft seal again. The stealership had already replaced it 3 times along with a new shift shaft. Took it to a family friends shop and they got it in correctly and no leaks so far.
navman28 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevy and GMC Duramax Diesel Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome