TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > Transmission & Drivetrain
  New Posts New Posts RSS Feed - Model 20 groaning on turns
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

Model 20 groaning on turns

 Post Reply Post Reply
Author
Message
7172AMX View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: May/20/2015
Location: South Carolina
Status: Offline
Points: 124
Post Options Post Options   Thanks (0) Thanks(0)   Quote 7172AMX Quote  Post ReplyReply Direct Link To This Post Topic: Model 20 groaning on turns
    Posted: May/13/2021 at 10:24pm
Evening,
Model 20 w/71 twin grip carrier. I've rebuilt several of these over time and never had issue. Since build when it gets warmed up (somewhat hot to be honest) she'll groan when the clutches slip around turns. Quite noticeable on tight turns. Could it be the synthetic lube? (limited slip purple stuff) Its the first time not using conventional base gear lube. The build was specd in every aspect per the FSM, preloads, runout, backlash, R&P inked, etc used a new set of clutches bought from AMC dealer circa 1980's! If it cant be the lube, its coming apart.
thanks and God bless 
GoPacKman
71 JavAMX 401 T-10 354TG
72 JavSST 360 727 315TG
98 Jeep Cherokee Classic 4.0 4WD
Back to Top
THE MENACE View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Nov/04/2008
Location: So. California
Status: Offline
Points: 4428
Post Options Post Options   Thanks (0) Thanks(0)   Quote THE MENACE Quote  Post ReplyReply Direct Link To This Post Posted: May/13/2021 at 11:47pm
When you install or rebuild a limited slip carrier it takes a bunch of tight figure 8"s to work the lube into the clutch packs to work properly.  

That being said, I tried synthetic gear oil once in my Jeep Dana 44 (with a power lock limited slip) and it did not like it! 

 The clutches would not slip smoothly in tight turns. It kind of popped instead. On top of that the cover gasket started leaking which I had never had a problem with ever with a rigid aluminum diff. cover. 

I drained the synthetic and filled it with conventional limited slip gear oil and it started working as it should again and the leak was gone too.

I won't do that again!!  

    
Former Owner of:
The Craig Breedlove "AERO AMX"

Still Owner:
SS/AMX #9 replica (THE BIG MENACE)
70 AMX 416, EFI, Nash 5 speed   
70 Javelin 401, 727 (Wife's)
72 Gremlin Autocross Project.
Back to Top
FSJunkie View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/09/2011
Location: Flagstaff, AZ
Status: Offline
Points: 4741
Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: May/14/2021 at 3:04am
Gear oils that say "for limited slip" on them often do not have enough friction modifier in them in my experience. The "for limited slip" on the bottle is more or less meaningless...

I'd squeeze in a bottle of friction modifier and run it for a while to stir it in before going any further. I've gotten so I just automatically add a bottle of friction modifier every time I change the fluid. 
1955 Packard
1966 Marlin
1972 Wagoneer
1973 Ambassador
1977 Hornet
1982 Concord D/L
1984 Eagle Limited
Back to Top
farna View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar
Moderator Lost Dealership Project

Joined: Jul/08/2007
Location: South Carolina
Status: Offline
Points: 19611
Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: May/14/2021 at 6:16am
I haven't bought friction modifier in many years, don't recall what it costs! Shouldn't be enough for you to try that first, and if it doesn't improve things after driving a bit (maybe a 6-12 tight figure 8s then a short drive around a few curves/blocks?) drain and try conventional lube. Some of the old parts just don't like synthetics, which are generally a bit thinner when cold for improved gas mileage, but hold up better under heat without thinning as quickly as conventional oil.
Frank Swygert
Back to Top
7172AMX View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: May/20/2015
Location: South Carolina
Status: Offline
Points: 124
Post Options Post Options   Thanks (0) Thanks(0)   Quote 7172AMX Quote  Post ReplyReply Direct Link To This Post Posted: May/14/2021 at 6:57am
Consensus! Thanks to you all and will try a lube swap ASAP and report in. 
Cheers
GoPacKman
71 JavAMX 401 T-10 354TG
72 JavSST 360 727 315TG
98 Jeep Cherokee Classic 4.0 4WD
Back to Top
Steve_P View Drop Down
AMC Addicted
AMC Addicted
Avatar
Charter Member

Joined: Jun/28/2007
Status: Offline
Points: 3760
Post Options Post Options   Thanks (0) Thanks(0)   Quote Steve_P Quote  Post ReplyReply Direct Link To This Post Posted: May/14/2021 at 10:17am
I've used Mobil 1 75W-90 in the clutch plate LSD without issues.  Agree about adding the friction modifier; the LSD spec gear oils often don't have enough additive as said.  
Back to Top
bobsterfl View Drop Down
AMC Nut
AMC Nut
Avatar

Joined: Jun/18/2009
Location: Orlando, Fl
Status: Offline
Points: 260
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobsterfl Quote  Post ReplyReply Direct Link To This Post Posted: May/14/2021 at 12:11pm
Try this stuff by Motorcraft.
Bobsterfl
1970 BBO Javelin
390 - Torqueflight
Back to Top
tufcj View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar
Supporter of TheAMCForum

Joined: Jul/10/2007
Location: Watkins, CO
Status: Offline
Points: 4066
Post Options Post Options   Thanks (0) Thanks(0)   Quote tufcj Quote  Post ReplyReply Direct Link To This Post Posted: May/14/2021 at 2:03pm
I've been using the Motorcraft stuff for years with no problem.Thumbs Up

Bob
tufcj

69 AMX
74 Javelin AMX
67 Rogue

If you need a tool and don't buy it...
you'll eventually pay for it...
and not have it.
Henry Ford
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.219 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or