Unidrive

[mikemc53 10]

My C-81 has the Unidrive 8 speed and I want to do some maintenance on it. I'm not the most mechanical guy but I usually get things done, somehow. I have read that this trans takes a 90-140 gear oil and I've seen posts where they talk about flushing and refilling, which is what I am looking to do. A question or two though:

 

The drain plug seems to sit in a spot that will require jacking the tractor up and leaning/tipping it to get a good drain. Am I seeing this correctly?

On this unit is the trans and rear-end one unit? When I flush and refill am I doing the trans and the rear end together or are there separate drains for each?

Thanks gang.

[Racinbob 11,232]

You're on the right track. Yes, it's all one unit and only one drain hole. Raising the front does get most of the oil out that's in front of the hump. You've gotta get her up pretty high to drain it good. See what the old oil looks like when you drain it. If it's nice you can just add 2 quarts of gear oil or dump in some diesel, drive it around a bit and drain again then refill. I've always used Valvoline 80w90 but 90-140 is fine. 

[pfrederi 17,885]

Drain plug 1/4" allen wrench  needed

 

 

[oliver2-44 9,870]

Since gear oil is thick set it in the sun to heat up to help it pour.  If the Allen head bolt that holds the gear shift in comes out easily, you can pour the new oil in there a little easier.  Your WH thanks you for doing the maintenance! 

Edited June 22, 2019 by oliver2-44

[tunahead72 2,433]

5 hours ago, pfrederi said:

Drain plug 1/4" allen wrench  needed

 

 

 

Notice the drain plug is on the bottom of the transmission case, not the square plug on the top.  No need to tip it to the side to get it to drain well.