Has anyone worked on their own diff? - Pontiac GTO Forum
User Tag List

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 22 (permalink) Old 02-22-2010, 07:49 PM Thread Starter
 
GM4life's Avatar
 
Join Date: Mar 2007
Location: RAF Lakenheath, UK
Posts: 4,162
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Has anyone worked on their own diff?

I'm having problems with my diff in GTO again. It was replaced under warranty Dec 2007. Well now I'm having the same problems again with the clunking and howling. Changed the fluid, still the same thing. So I'm going to tackle this, to see whats up with it. Is there any service manuals that cover the specs of the diff, backlash, ect? The GM service manual covers very little about the diff. Also what special tools I need?



GM4life is offline  
Sponsored Links
Advertisement
 
post #2 of 22 (permalink) Old 02-24-2010, 01:43 AM Thread Starter
 
GM4life's Avatar
 
Join Date: Mar 2007
Location: RAF Lakenheath, UK
Posts: 4,162
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Nobody?



GM4life is offline  
post #3 of 22 (permalink) Old 02-24-2010, 02:06 AM
 
Join Date: Jun 2009
Posts: 2,777
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I was going to check my new Helms manual, but sounds like you already got one (awesome, btw).

Just working from theory here, your clunk would be from excessive lash, and the howling would be from excessive pinion/ring gear tooth wear (which would cause lash over time). You are one of the lucky guys with a Maggie, so its entirely possible that your motor beat the snot out of your gears.

Good question, though. This will definitely take some investigating, and I'm sure this will help out more than a few people in the future.

Are you just going to do the gears, or are you planning on upgrading to like a TruTrac?
Poncho Dan is offline  
 
post #4 of 22 (permalink) Old 02-24-2010, 02:20 AM Thread Starter
 
GM4life's Avatar
 
Join Date: Mar 2007
Location: RAF Lakenheath, UK
Posts: 4,162
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
No, I don't beat on my car I pretty much pu$#yfoot the thing because I'm still on the stock driveshaft. I used to give Dana big prase for their bulletproof diffs they was the TH400 of diffs. This diff seams to be so finiky and crappy its unbeleavable.

What I wanted to do was drop the cover and check the gear faces to see if they have any abnormal ware. If not then I would like to adjust the lash and press foward. If not would like to upgrade the gutts if the wife lets me.



GM4life is offline  
post #5 of 22 (permalink) Old 02-24-2010, 02:34 AM
 
Join Date: Jun 2009
Posts: 2,777
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Yeah if you see any kind of cupping on the tooth surfaces, then they're toast. I wish I knew of a way to measure them in a non-arbitrary way with a dial calipers.

Perhaps my Machinery's Handbook will say something about excessive lash...
Poncho Dan is offline  
post #6 of 22 (permalink) Old 02-24-2010, 03:16 AM Thread Starter
 
GM4life's Avatar
 
Join Date: Mar 2007
Location: RAF Lakenheath, UK
Posts: 4,162
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I can't find data on this diff, no torque figures, backlash settings, how to adjust it, nothing. Have to get rid of the intermittin clunk and the whining at 45-50mph under load.



GM4life is offline  
post #7 of 22 (permalink) Old 02-24-2010, 09:38 AM
 
Join Date: Apr 2006
Posts: 242
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
rear end removal thread- LS1GTO.com Forums
swapping the gears-
LS1GTO.com Forums - 3.91 Gear Install...GHETTO Style


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~
Thank you Kurt from Diff Technics for the following:

IF the 3.46 ratio pinion that you “take” out of the diff has lets say a marking
of 0 and then the 3.91’s we sent you have a 2 marked on them this would mean
that the 3.91 pinion is .002” further into mesh with the ring gear than the 3.46
so you must remove .002” from the pinion location shim if it was the other way
round and the 3.91 pinion had a -2 (negative two) on it this would mean that the
pinion is .002” out of mesh with the ring gear center line, So hence you must
ADD .002” to the shim size and if you were luck enough to have 0 put it straight
in !!! I hope this helps you out on the location side of things !

Now as for the back lash .004” to .006” back lash is a must no more no less on
these ring and pinions !


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~

These are the stock (dana) specs for the LSD

1. Pinion Gear Bearing Pre-load 25-35 In Lbs (1.32-1.54 ft lbs), Add 8-12 In Lbs
If The Seal Is Installed. Light Machine Oil Only, No Gear Oil For Pre-load.

2. The Torque Spec On The Crush Sleeve Is In The 150-500 Ft Lb Range With 230ft
lbs The Usual Number Needed To Get You Close.

3. The Side Cap Carrier Bearing Pre-load Is 41-51 Ft Lbs With Final Adjustment
(load) Preferred Towards Pinion Gear. Light Machine Oil Only, No Gear Oil. Turn
the carrier approx 20 times or so, re-check the torque spec.

4. Backlash is 4-7 thousands with tooth pattern preferred over tightness. He
indicated a center to lower (towards small side of ring gear) contact preferred.
this should keep it quiet.

All Seals Should Be Greased With A High Quality Grease (i Prefer Moly on seals
and never used anything else) To Keep The Seals From Burning Out Prior To
Seating Up To The Metal Parts They Are Meant To Seal. Do Not Install Them Dry.

1) AXLE ASSY
2) BOOTS
3) INNER CV JOINT
4) OUTER CV JOINT
5) FLANGE
6) HOUSING
7) CARRIER COVER
8) AXLE SHAFTS
9) AXLE SEALS
10) DIFFERENTIAL CASE
11) SIDE BEARINGS
12) GEAR KIT
13) RING and PINION
14) REAR PINION BEARING
15) PINION SPACER
16) FRONT PINION BEARING
17) PINION SEAL
18) COMPANION FLANGE

Attached Thumbnails
Click image for larger version

Name:	GTO_lsd_alt.gif
Views:	15981
Size:	9.2 KB
ID:	6627   Click image for larger version

Name:	GTO_lsd_big.gif
Views:	12836
Size:	63.4 KB
ID:	6628  
Ninjured is offline  
post #8 of 22 (permalink) Old 02-24-2010, 02:16 PM Thread Starter
 
GM4life's Avatar
 
Join Date: Mar 2007
Location: RAF Lakenheath, UK
Posts: 4,162
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks Ninjured, that helps me out a lot. Now it looks like I have to get some special tools, daaamn! Looks like this will be my first diff work, I can't go wrong with something thats allready jacked. Hopefully they're not worn to the point where I need to replace.



GM4life is offline  
post #9 of 22 (permalink) Old 02-24-2010, 02:22 PM
Super Moderator
 
6QTS11OZ's Avatar
 
Join Date: Mar 2005
Location: Where the women are scarce and the sheep are scared. So. Cali
Posts: 2,639
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Yo Justin. Since this is your thread and it has some valuable info you ought to make it a sticky for future reference.

~I'm ya huckleberry~
~516rwhp/500rwtq~

http://www.youtube.com/watch?v=yC11NCGTEvI
6QTS11OZ is offline  
post #10 of 22 (permalink) Old 02-24-2010, 02:53 PM Thread Starter
 
GM4life's Avatar
 
Join Date: Mar 2007
Location: RAF Lakenheath, UK
Posts: 4,162
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
It is some good info. I was getting a headache last night tring to find info about this diff. My google skills must suck because I was getting everything from handbags to insurance compaines.



GM4life is offline  
Sponsored Links
Advertisement
 
Reply

  Pontiac GTO Forum > The 2004-2006 GTO > Drive train, suspension, alignment and brakes.

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Pontiac GTO 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











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



Similar Threads
Thread Thread Starter Forum Replies Last Post
Diff ques rcollamore Drive train, suspension, alignment and brakes. 1 02-05-2009 02:12 PM
It Worked!!! AlanSr Intake and Exhaust Discussions 11 06-03-2008 08:03 PM
04 diff/05 diff banshee 2004-2006 GTO General Discussion 8 08-23-2007 09:26 PM
Got worked by truck dealernut Racing and Kill Forum 11 02-03-2006 07:26 PM

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