Gibson Super D2 Tractor T96 Shifter Repair

When I bought this tractor, I knew either the shifter or transmission needed help, as it was sometimes almost impossible to shift between gears, and on a couple of occasions got stuck in two gears at once. I've had the shift tower off the transmission several times, greasing and oiling to no avail, and finally the last time I had it off (always the last time, right), I realized what was going on. The shift lever was twisting sideways and causing the square bottom end of the shift lever to bind between the two shift forks when in gear (red arrow below).

The transmission used in many Gibson tractors, mine included, is a Warner Gear T96 three-speed, also used in Jeep/Willys and other cars of the day. Behind the Gibson's 12hp Wisconsin TF engine, this transmission should last forever.

This next photo shows the shift tower disassembled. The spring to the left holds the shift lever into the tower from the bottom side.

This next photo shows a very worn pin. This pin engages the slot in the shift lever's ball joint (see next photo) and keeps the shift lever "clocked" so it doesn't rotate side to side. The pin is worn almost 1/8" thinner than the slot in the ball, causing the square bottom end of the shift lever to bind in the shift forks.

This next photo is the shift lever ball joint with the slot to engage the pin. Notice the slight elongation in the slot. I didn't bother trying to repair that.

The pin measures .215 inches in width. The slot in the shifter measures .312 (5/16"), so almost 1/8" of slop between the pin and slot, which allowed the shift lever to rotate and bind the square end against the shift forks.

The next order of business was to remove the pin from the shift tower. I didn't know which direction to pound the pin so I started hammering from the inside out but it didn't budge. I then noticed the pin seemed to be peened over on the outside of the tower so I ground away at it, which then revealed that the pin needed to be driven from the outside in.

The pin is removed.

I made a new pin on the lathe. Dimensions are: 1/4" diameter by 7/16" long on the small end and 5/16" diameter by about 1/8" long on the big end.

The pin was pressed into the hole using pliers. Now to peen over the end poking out, although the pin isn't going anywhere when the shift lever is in place.

Here the shift lever is back in the tower, held in by the funky spring. The spring was difficult to remove but was fairly easy to tap back in place under the three tabs cast into the tower. I could tell the square end of the shift arm has previously been repaired (welded and ground). And it was nice that I only had to remove one shift rod and fork to do this repair.

The last step was to reinstall the shift rod and fork, then tap the roll pin back in place.

I took the tractor out for a spin and the shifter now works as it should.