Other
Transmission Trouble and Remedies


SYMPTOMS

PROBABLE REMEDY

Slips Out of High Gear

 

Transmission misaligned with Bell Housing

Align transmission case to Bell Housing and Bell Housing to Engine

End play in Main Drive Gear

Tighten front retainer or bearing requires bushing

Damaged Pilot Bearing or Front Bearing

Replace

Bent Shifting Fork

Replace

Interlock Plunger Not in Place

Install

Slips Out of Second

 

Bent Shifting Fork

Replace

Worn Gear

Replace

Weak Poppet Spring

Replace

Interlock Plunger Not in Place

Install

Noise in Low Gear

 

Rear Ball Bearing Broken

Replace

Gear Teeth Pitted or Worn

Replace Gears

Shifting Fork Bent

Replace

Lack of Lubrication

Drain and Refill

Slips Out  of Gear

 

Weak or broken poppet spring

Replace

Interlock plunger not in place

Install plunger

Transmission gears or bearings worn

Replace

Shift fork bent, causing partial gear engagement

Replace

Transmission loose on bell housing

Tighten

Damaged bell housing

Replace

Noise in Low Gear

 

Rear Ball Bearing Broken

Replace

Gear Teeth Pitted or Worn

Replace Gears

Shifting Fork Bent

Replace

Lack of Lubrication

Drain and Refill

Hard Shifting

 

Interlock plunger missing

Remove transmission and transfer case, install interlock

Clutch fails to release

Adjust clutch pedal free travel or replace

Gear shift end worn or damaged; binding in housing

Replace

Shift plate worn or bent

Replace

Shift rods binding in case

Replace, check case for damage

Transmission loose on bell housing

Tighten

Clutch shaft pilot binding in bushing case or shift housing damaged

Replace pilot bushing, measure pilot end for tolerance, examine housing

Grease Leaks into Bell Housing

 

Cup missing from shifter rail

Replace

Gasket Broken Front Bearing Retainer

Replace

Transmission Case Overfilled with Lubricant

Drain off to proper level

Excessive Noise

 

Incorrect driving practice

Correct practice

Insufficient lubricant

Add lubricant

Incorrect lubricant

Correct practice

Gears or bearings broken or worn: shift fork bent; gears worn on spline

Examine and replace faulty parts

Overheated transmission

Check lubricant grade and supply

Loss of Lubricant

 

Worn or damaged seals or gaskets

Replace

Overfilled with lubricant

Drain to proper level

Pumping lubricant from transfer case

Install recessed spacer and internal seal

Loose bolts and screws

Tighten

A lot of the problems you might have with your transmission can usually be attributed to just a few parts.

  1. Gear shift
  2. Shift plate
  3. Interlock plunger missing
  4. Synchronizers worn

A worn gear shift will play on your nerves. It doesn’t take a whole lot of wear on the cam shaped end of the stick and the next thing you know you’re having trouble in the transmission.

It’s unlikely but you might have an early shift plate which is more readily bent then later plates. The later shift plates had an extra “U” shaped plate to add strength. However, like as not, it is just a well worn plate that is adding to you trouble.

Some fellows think that leaving out the interlock plunger makes it easier to shift. In fact it can make it harder to shift. It’s easy to forget to put the plunger in place when assembling the transmission and transfer case together...so DON’T FORGET!

The synchronizer contains brass parts that wear more readily than steel. These parts have the responsibility to help keep your transmission from grinding gears and eliminating the need to “double clutch.”

Of course, in a 60 year old transmission it could be that you have a combination of issues, all related to wear and abuse. This wear and abuse can be rapidly caused by using the “wrong” type of gear lube. Another issue is noise. Some jeep enthusiasts are convinced that a jeep transmission has to be noisy. They believe that they all are noise makers. That is just not true! Using new gears and shafts, your “like-new” transmission will be quiet.

Of course, the T84J is not going to be as quiet as a transmission in a modern car but it will be a huge improvement. When I had my full enclosure set up on my jeep I would need to wear ear plugs with the cacophony of noise coming from the transmission. After rebuilding my transmission with new gears and shafts—no longer do I need the earplugs.

My philosophy is “if in doubt, replace the part”. It is a false economy to rebuild your transmission and not to replace questionable parts. Of course that doesn’t mean you have to replace every part but you want to carefully measure or examine the parts for wear and tear.

With a modicum of care and maintenance, the rebuilt transmission will last a long time.

Source: TM 10-1349, Change 1, May 1, 1943 and Trouble Shooting And Rebuilding The T-84J

©2006, Robert V. Notman, all rights reserved. See Legal Notices.