Need help on compatibility

[lae51967 18]

I bought this transaxle several years ago and I failed to log its origin. I have posted it for sale in the Facebook groups. I was asked if it would work in an 857. I'm hoping someone here may have the answer to that question.

[kpinnc 13,124]

That is a later model 8-speed. Probably a "Classic" model (300/400/500 series) just based on the dipstick and drive pulley. 

 

Short answer: it will work on an 857, but the clutch/ brake linkages will have to be modified as the 857 used a 3 speed. Externally both transmission models have the same dimensions and bolt to the frame identically, but there are minor differences in the connections to it, as well as the 857 frame not having a place for the dipstick tube.  

[ri702bill 8,761]

A few of us, myself included, have installed the C series 8 speed in early Round Hoods. So has @Pullstart on his 502. From memory, here is what I had to do on my 854:

 

The input shaft is 5/8", not 3/4" like the 4 speed. You need a replacement pulley with the outside diameter of the 4 speed one, but with the 5/8 keyed bore. I got mine from McMaster.

After changing the pulley, the stock 70 inch belt acted too long - had to get one 69" long.

My 854 has a fixed seat - the dipstick tube and dipstick had to be shortened about 3-3/4 inches to allow the dipstick to be removed.

Cutting the dipstick - start off with the Unidrive filled to the original full mark, shorten the tube and dipstick, assemble to find the new "Full" line. I used a trianguler jewelers file to put a fine line on it.

Brake linkage - the 8 speed band is pulled, not pushed to activate. Got the link from a Raider 10 - worked fine. Note: could not hook up the parking brake, but 1st gear in Low Range is almost as good.

The hole for the HI-Lo lever - I painted the top of the shaft protruding up with grease, set the tin on it to get a transfer mark. Drill a small - 3/16" or so - starter hole thru, reassemble & adjust if it is not centered. The use a 1" hole saw & cut thru.

I reused the 4 speed shifter and shortened the Hi-Lo lever.

Looks like you need a new shifter boot - is there any moisture inside the Unidrive??

 

Doing a 6 speed swap, like @Handy Don did on his 854 is easier - input pulley & brake are the same as the 4 speed. there is no dipstick or tube to cut.

 

 

Edited 23 hours ago by ri702bill

[lae51967 18]

Thanks for the input guys. The potential buyer is in this group so I imagine he'll be hopping in here as well.  No moisture that I'm aware of.  I've stored it in a heated garage since I bought it.

[Pullstart 63,560]

It bolts in, but is not a direct swap.  I did mine long before I was a regular on the forum.  It was a need, not want.  I had no instruction, but it wasn’t too hard.