Thread: Gearbox revelations

Some time ago I swapped the 4 spd out of my '84 110 to get it rebuilt, replacing it temporarily with another 4 spd from a '76 Rangie. I didn't have the time or gear to do this myself, so 'Mechanic 1' did the job for me. All was good, I gave the original box to be rebuilt to 'mechanic 2, since renamed 'Mr Silastic & Son', who also installed it back into the 110.

This process should have been simple enough, but it became an ongoig saga as the 110 had to be taken back the Silastic & Son several times to sort out a range of problems that, in all fairness, were not all his making. Some fundamental ones however, were.

First up, the output flange was put back on without the washer, and with the incorrect oil seal, so not only did it stream oil, the flange was also loose on the shaft. I put a new washer on, also removed about 1/4 tube of silastic from the flange, and did it all up only to find the brake drum now pulled tight onto the backing plate, locking the drum solid. Somehow the output shaft was now about 5mm shorter than before the rebuild. I did a dodgey repair, spacing the brake drum off the flange with a couple of washers so I could get the Landy back to Silastic & Son. Twice.

This problem was really caused by me having two different mechanics swaping boxes, as we'd accidently put the output flange from the Rangie, which turns out to be 5mm shorter, onto the 110 box. After we swapped these back everything fit, but still we had 0.5mm lateral movement in the output shaft. Neither silastic & Son nor Mechanic 1 could fix it.

I took a punt that as the output flange was the wrong one, the output shaft in the 110 might also be from the Rangie box. The spare shaft also had a machined 'knurling' of sorts on the outside surface of the spline which fits into the centre diff. As it is only this and a ball bearing that holds the shaft I figured it could be a tighter fit and reduce the movement. So the back end of the box came off a-bloody-gain, shafts swapped and reinstalled.

Guess what... It's fixed! No more movement.

A few other lessons were learned here; both thes boxes had a history of jumping out of either high or low range. The cause of this I found during the final shaft swap, and it was dur to silastic & Son's enthusiasm for goo. when fitting the output housing it is easy to get silastic into the recess for the range selector shaft, which can form a solid plug that will stop the shaft moving into the low range position. It can also get around the end of the selector shaft and fill the recess that the locating ball should occupy, therefore not securely holding the shaft in the high range position. So don't panic about the prospect of a rebuild on account of the range selector throwing out, it could be as simple as what I found.

I'm having trouble attaching photos at the moment but I'll see if I can send them later.

Got it! The photos are in the pdf document. They are not great, but may help someone.