TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > Transmission & Drivetrain
  New Posts New Posts RSS Feed - Model 20 feels
  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 feels

 Post Reply Post Reply
Author
Message
CHAR View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Feb/22/2019
Location: NW Florida
Status: Offline
Points: 110
Post Options Post Options   Thanks (0) Thanks(0)   Quote CHAR Quote  Post ReplyReply Direct Link To This Post Topic: Model 20 feels
    Posted: Jul/12/2019 at 11:46am
Ive got this problem, see?  I test drove my '72 before buying it and it ran as fine as can be expected for something that had been laid up for three years in a garage.  No noise, wobble, rumble or vibrations in forward or reverse.  Took it home, tore the wiring out of it, rebuilt the carb, got it purring like a kitten and when it was time for a test drive it wouldn't move.  It will shift (727TF) into reverse and the car will lurch when I give it some throttle - got the left rear wheel to spin, and it is a twin grip, but it would stall.  I thought maybe E-brake was hung up. On a jack with both wheels free it goes into reverse and drive and the wheels turn accordingly with no brake noise.  Same thing by hand. BUT and this is why I'm in this part of the garage, is that when I turn the rear wheels by hand, there is a thumping feeling transmitted thru the axle shaft.  Is that just the ring and pinion?  its not a grinding or anything, just this bump bump bump in my hand.  The axle feels solid in the outer bearing, it doesnt wallow around, (I've only check the pass. side before the rain drove me indoors, and the drive shaft u-joints look and feel tight as well.

The brake on that side looked good and operated as it should.  still have to check the driver side rear and the fronts to see if they are locked up, but it will roll forward but Im out of room in that direction.  Am I supposed to feel the gear set rolling over like that?

Thx
72 Javelin SST P code 360/auto/A/C/ rear defrost option/white on blue
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: 16355
Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Jul/17/2019 at 6:28am
The "bump-bump" is most likely the Twin-Grip and is normal when you turn one wheel.

Make sure you have the trans linkage hooked up and adjusted correctly. Also the kick-down rod. The kick-down rod also controls internal transmission pressure (increases pressure with throttle so it shifts smoothly). If it's not connected or adjusted properly you can burn up the transmission. If missing or you have trouble adjusting it get a Lokar cable for a 727. I don't think they list AMC specifically in their parts book, but any of the Chrysler 727 applications will work. It's much easier to adjust and keep that way.

If the linkage is correct you have an internal transmission problem. Start by checking fluid level in neutral (not park!) . Maybe it's leaked some just sitting? If that doesn't solve the issue you will need to pull the trans pan and inspect the shift linkage there. It's likely fine. The next step is to pull the valve body, take it apart, and thoroughly clean it. you could take it to a shop and have them do it. Don't take apart without a manual! There is a 73 manual here that should do the trick - http://www.oldcarmanualproject.com/manuals/AMC/1973/Service/index.html
Frank Swygert
Back to Top
CHAR View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Feb/22/2019
Location: NW Florida
Status: Offline
Points: 110
Post Options Post Options   Thanks (0) Thanks(0)   Quote CHAR Quote  Post ReplyReply Direct Link To This Post Posted: Jul/17/2019 at 3:22pm
Thanks Farna.  The kick down cable was the first thing I ordered after purchasing the car.  My Scout II has a TF 727 and the cable makes things a heck of a lot more reliable.  The oldcarmanual site has been helpful since the start.  The '72 TSM that came with the car is a poor copy and there were no wiring schematics in it.  The Trans throttle was disconnected when I measured it for another member and rebuilt the carb, but its positions were marked and matched during re-installation.  Checked for leaks -nothing on the ground.  I'll just keep hacking at it.  Thanks

C
72 Javelin SST P code 360/auto/A/C/ rear defrost option/white on blue
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.125 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