I am converting from a tail shifter to a side shifter. I have one but its history is unknown to me - it came out of a parts car that I've had for 10 years or so and it had been sitting in a dead car for unknown years before that. I've never rebuilt one so I approached a local expert about rebuilding it prior to putting it in the car but he recommenced that I stick it in and run it to get an idea of its condition before I spend any time or money on it. Not a bad plan just not what I had in mind.

I have cleaned it up and built a bracket to hold the accelerator linkage pivot shaft but after filling it with fresh oil, I've noticed that its leaking from the driver's side output shaft.

Can the seal on this side be replaced easily?

Yes, output shaft seals are pretty straight forward to replace. Just drain the oil, remove the shaft and replace the seal.

I don't remember the torque setting on the shaft nut, but it is pretty low ...

Do you have all of the other parts needed to make the conversion to the side shift Trans? If you dont have them i have most if not all of them. And you have 6 in it?

With this limited info, the transmission could be functioning perfectly or impossible to get into first without grinding. The sycnros are the most common issue with 901 transmissions.

If the transmission isn't in the car, I assume you've spun the input shaft and shifted and all felt fine?

I think Dr Evil has a video of how to rebuild the transmission if you're interested in that. He did mine before I installed it and it was a good thing. The intermediate bearing was toast.

Torque is 18 ft/lbs....according to Dr. E.

IMO you need to replace ALL the seals on the box otherwise you'll likely have more leaks in a short amount of time. Input seal, shift console seals, speedo seals, axle output seals. If the box turns out good,it would save you some headache.

It is so easy and not expensive to change the seals while it is out of the car and as mentioned it is likely that other seals will start leaking shortly.

Jeff B

Fix whats leaking now, keep an eye on it and take it out over the winter to service the entire unit. Don't loose valuable drive time now unless you have to.

It's easy to do that output flange seal with the engine & trans in the car.....

One thing to consider, and is common, especially in a box that sat, is that the output flange shaft is pitted and a new seal will not fix this. I have good flanges if you find you need one. Seals, too. All parts, really. Yes, still have DVDs for sale

I would pull the flanges from the spare box, check the sealing surface, and replace the leaky side flange if indicated. Do both output seals and input shaft seal as its cheap and easy to do while you are there.