8 Speed with a Diff Lock?

[Raider12 13]

I have a 1971 Radia 12 with the 8 speed. I would love to make a diff lock for this diff. As anyone tried this before?

[Curmudgeon 28]

That tractor has the limited slip 10 pinion differential in it. Not a locker by any means, just limited slip as the name implies.

Do you want it locked up solid all the time for pulling? The 10 pinion isn't near as strong as an 8 pinion, which may be of little concern if you somehow lock things up solid.

[Raider12 13]

What I wanted to do is make so I can lock it up only on a as needed bases. I was looking to see if anyone has ever done this before. What models have the 8 pinion diff? I have even concidered going to a hydro set up. Is the hydro diff any different of a differrential? Im kind of new with the tinkering with these old tractors. This radair 12 I have owned now for 18 years and would not give it up for anything. I have a pic of mine on my profile. I restored it about 16 years ago. But after being used to mow and plow every drive in the alotment, it needs some TLC. This winter I plan a complete make over. Thanks

[TT-(Moderator) 1,131]

I'm sure if you had the money, you could fabricate something to lock the differential, but I can't really see why you'd have to.

It would require a complete redesign of the differential, and there really isn't that much spare room inside the cases for extra parts either.

If that 10 pinion limited slip differential is functioning properly and you have enough weight on the Raider, it should do almost anything you ask of it -- otherwise, you might want to look into the Caterpillar brand of equipment. B)

[Curmudgeon 28]

I'd have to agree with TT. Anything can be done if money and time is no object, but few of have both of those options.

The list of tractors with the 8-pinion is LONG to say the least. There are hundreds of tractors, but only a handful of different differentials in all of them. Even the 4-pinion models can sometimes be made 8-pinion simply by putting 4 more pinions in them.

[kpinnc 11,881]

What models have the 8 pinion diff?

On any of the trannies that use the 10 pinion, you can replace them with an 8 pinion. I think, for that matter, that as long as the axle diameter is the same from the "donor" tranny as the one you're putting it into, you can replace ANY of the differentials with an 8 pinion.

That remark comes with the following disclaimer: I have never seen a tranny with 1 inch axles and an 8 pinion diff. Supposedly, some of the 310-8 trannies had extra holes in the carrier to add 4 pinions to make them an 8 pinion. Per the model number, my 310 was supposedly a candidate for it, but I found out it in fact did NOT have the extra holes as the manual claimed...

To get to the point, you can swap your Raider's differential with an 8 pinion with no problems. It is a MUCH stronger differential than what you are using. BUT, if traction is what you're looking for, then you have the best setup available already. Unless you're trying to pull stumps or something with it, you probably don't need to change it.

Just my .02...

Kevin

[Raider12 13]

Ok. with all this said, (im learning here, be patient) how much stronger is the 8 pinion over the 10 pinion? I can get a differential out a early 70's charger as well. Is the 10 pinion a limited slip and 8 is not? I have been working the fire out of this tractor moving piles of dirt and doing landscaping in my lawn. I have had the mid mounted grader blade on it this week and the dozer blader as well. I pair of ag tires and wieghts and will dig to china. But this winter I want to start from scratch and Im trying to do my home work now. Thanks everyone for you in put.

By the way, is there a "Book" I can buy that tells me all the different models and their details etc?

[TT-(Moderator) 1,131]

The strongest OEM transaxle you will find is the 8 pinion 1 1/8" axle equipped Uni-Drive. These were in most of the C series tractors and a few of the 300/400 (and 520 8 speed) tractors. They are an open differential, but with weight and good tires will provide great traction.

The Charger differential should also be a 10 pinion, but that varies with certain models. You should assume that it is, unless someone previously changed it.

The reason the 10 pinion is weaker is because the ring gear center is machined out more to accept 10 pinion gears instead of 8. The pinions themselves are also smaller so they can all fit into that space. The limited slip part is a spring collar forced inside the ring of pinion gears causing them to equally drive both axles until the tractor is turned and the inside wheel slows down. I feel safe to say that with a stock engine and normal usage (proper maintenance too) you won't hurt a 10 pinion rear.

You could also buy a used 8 pinion 1 1/8" axle Uni-Drive, freshen it up, (bearings, seals, and new oil) and install it in your Raider. It should last another 20 or 30 years under civilized conditions.

[kpinnc 11,881]

I agree with TT, not much you can do short of something kinda stupid to tear up the stock tranny with 12 HP. By stupid I mean dumping the clutch under heavy load, or dragging a 21 foot tandem axle trailer around in the yard, etc... Yes, I know these things will break it.

By the way, is there a "Book" I can buy that tells me all the different models and their details etc?

Your best bet is to get the model number of whatever tractor you're looking at, and plug it into the Toro parts viewer online. Most of the tractors have an exploded parts view of the trannies.

Key being the MODEL number, not the name.

Ex: 1-420 = 1971 Bronco 14

1-422 = 1972 Charger 10

21-10k804 = 1987 310-8

Also, if you decide to replace the differential, it may be easier to just replace the whole tranny. You can bolt any 4 or 8 speed into the same place another comes from.

Again, you've got a nice setup. You won't find one that gets better traction.

Good luck,

Kevin

[Raider12 13]

Im thinking that with what I have learned here today I will stay with the differential I have and this winter I will go through it with all new seals atc to frsh'n it all up. The tractor is getting a piant job and detailed to show room new condition. Thanks eveyone for your help.

[Curmudgeon 28]

Mechanical Transmission Repair Manual #492-4004