901 gear assembly swap

[iamchappy]

I have one stock 1973 901 tranny with a rebuild of less than 10,000 miles on it, and one 1973 901 with quaffe lsd and short gears, I recently turbo-charged my 3.0 and think that the stock gearing may be better suited for the engine now, after removing the back covers can I remove the complete gear assembly and pull it out whole and swap them, I would still like to keep the quaffe lsd but run it with the stock gearing.

[John Rogers]

I don't think you can just do the swap due to the setup required on the ring and pinion and the LSD unit. I had pretty much the same setup and had both trannys done over since they needed bearings anyways. James (Redbeard) can say for sure?

[john walker's workshop]

yes the gear cluster can be removed as a lump. first, observe the two ends of the shift rails sticking out of the intermediate plate a bit. tap the upper one all the way in. this moves the shift sleeve on the mainshaft inward so it clears the case as you remove the cluster. you will have to assemble the stock gears onto the pinion shaft that was running with the ring gear that has the LSD on it. use the case it was set up in, and measure the thickness of the gasket between intermediate plate and the main housing, as this relates to pinion depth.

[iamchappy]

I'm a little confused but it's because I am not looking at it right now or have a picture in my head of what your describing. I am familiar with whats behind the rear cover but not whats behind the intermediate plate. I know how to go about tapping in the shafts on the 4th 5th in order to remove the assembly but I have never actually done it. I will look over redbeards
how to rebuild and familiarize myself a little better with the procedure. Are there different types of gaskets used and available that make up the depth of the pinion based on thickness. Thanks for the great advice.

[lapuwali]

Basically, the entire set of gearbox internals are "hung" on the intermediate plate. Removing that plate removes everything except for the final drive.

On the end of the output shaft is the final drive pinion. It's "depth" wrt the ring gear is set by the gasket like shims between the intermediate plate and the main gearbox case. Unless you are very lucky, the depth required to get the pinion to fully engage the ring (but not engage it too much) will be different between the two gearboxes, and the only way you'll determine it is through a trial and error process that's too long to document here.

If the depth is wrong, you will at best have a very noisy final drive. At worst, you'll chip teeth off it. Considering you're going to be putting a lot of torque through the thing, it will really need to be right.

[iamchappy]

Would it be much simpler or easier to swap the Lsd into the stock tranny instead of pulling out the entire gear clusters on both.

[red-beard]

Yes.

[iamchappy]

red beard are there any tricks to this that I should know about or any instructions already posted that I haven't found.

[red-beard]

Read through my tranny article. There are some tricks for getting the stack out of the tranny.

When you remove the differentials, you will need to keep the ring from the stock tranny and install this on the LSD. You have to keep the ring and pinions together.

Get the paper gaskets and note the color and number of gaskets used between the intermediate plate and the case.

You may want to consider replacing the side cover o-ring, even though it is almost new. The O-rings flatten out in use.

James

[lmcchesney]

Red-Beard,
What is the link to your tranny article?
L. McC

[red-beard]

http://home.san.rr.com/pb914/rebuild/

[Dave at Pelican Parts]

Hmm... Might make a good link to put in your sig?

--DD