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1991 vf 1 gearbox rebuild


Feb 4, 2014
Here I am pulling off the main bearing. Notice the seal behind it. It's an aluminum disk with an o-ring on the outside and the seal gets pressed in on the inside..
took a week to get the bearings and seals in.. I set them side by side to make sure I knew which was which.. I had marked the old ones with a sharpie and where they went.
The main bearing has to be installed in housing followed by that funky seal first before installing the gear shaft.. I used lots of petroleum jelly and still sheared off a bit of o-ring.. it's tight enough i'm not seeing a problem. I had to have the guy's at priest electric press on the gear shaft then install the pulley. They have an induction heater so it was a piece of cake for them to do.. Thanks guy's..View attachment 69956View attachment 69957View attachment 69958View attachment 69962View attachment 69963

Can you tell me if you replaced the Gears? and if so where did you get them from?


Feb 25, 2018
Ok, gunna pull this one back out.

Eksinger, did you keep a parts list of all the items ?

My transmission (1-'91 VF-1) and tho still full of oil, it has rubber "cushions" surrounding the 6 mounting bolts which prevents me from tensioning the belt in the manner found in the '93 and newer manuals. Does ANYONE have info on these bushings, a part number (hahaha) maybe an actual service manual for the '89-92ish machines etc ? I measured my belt as the 800-8MGT-21 and replaced it with the 20mm GT3 version instead due to cost and availability of new old stock 21mm belts

diyengineer253, you mentioned having 3 extra transmissions. Do any have the rubber cushions ?​

Mine is such a great machine, I want to keep it running as long as I can. I did a full teardown and repair/replace back in early 2020 and only have had a few "minor" issues since. Most all were plunger switch related and cheapish to resolve. The most recent, and the most frustrating is my spindle drive (Mitsubishi FR-Z220) is acting up and periodically turns off/on during a program. It's a physical issue as I've made it happen when gently tapping on the removable chips on the main PCB so I cleaned and reseated said Chips and fingers crossed. If that didn't cure it, time for a new VFD.