8 Speed Transmission Case to 6 Speed??

[oliver2-44 10,893]

Is the 8 speed transmission case the same as the 6 speed case?

I have 2 spare 8 Speeds and wondering if I can build a 6 speed without too many replacement parts.

No 6 speeds around here so far.  A six speed would be nice since its directly interchangeable with some of the  3-4 speed brake linkages and the 953/1054 brake linkage.

So I been studying the transmission manual, parts list, pictures and @stevasaurus videos trying to determine if a 8 speed case could become a 6 speed.  I know the brakes are on different shafts, but looking at part list drawings and pictures it sure seems the angled brake band mount is the same. I'm thinking they just made the brake band a little different.  I would need a couple of different gears, but a lot of them are the same.  The bearing holes in the cases look the same best I can tell from pictures.  @Racinbob I know you recently had a 6 speed on the bench.  If you or anyone have a way to compare the 2 cases, especially the brake band mount and bearing hole sizes I would appreciate any comments you can share. 

 

The next question is can an 8 pinion differential be used in place of the Limited Slip Differential.  I seem to recall reading it can, but haven't found that info again.  I wouldn't mind a LSD, but I already have a good usable 8 speed diff with 1-1/8" axles. Are the 8 speed differential gear to 6 speed brake shaft gear teeth count compatable? 

 

I appreciate any info and thoughts ya'll can share.

[oliver2-44 10,893]

Doing a little more looking, I see the 5060 parts list show a right case #7066, left case 6941 and the 103916 8 speed shows a right case as 8163  and left case as 6941

So the right case halves have different part numbers and the left case haves have the same part number.

They sure look the same in pictures, so what's the difference?

[Racinbob 12,139]

I've wondered about that a few times but short of actually doing the change it would be nearly impossible to know for sure. Having one of each open at the same time would help. I think the cases will interchange. The obvious would be bearing changes and different shafts. The 8 speeds use a brake rod that goes over the top of the drum and has a dogleg in it. The 6 speed rod is straight and shorter. The brake bands are reversed but it might be possible to interchange. As far as the case part #'s often times Wheel Horse changed something insignificant that really doesn't affect interchangeability. I'm thinking it's possible to change an entire 8 speed for a 6 speed with nothing more than some simple linkage changes. But again.........I haven't actually done it.

[ri702bill 9,821]

Having done an 8 speed swap on my 854 years ago, this much comes to mind.

The 6 speed is a simpler swap, the input shaft & pulley are the same, externally, as the 4 speed. The brake & parking brake are in the same location. Ask @Handy Don.

The 8 speed is the opposite on these two items - the input shaft is 5/8", not 3/4". This nesessitates a special new pulley. The brake band mounting is reversed - the action of the rod goes from push to pull. I used a Raider style ros for this. I did not bother to try to come up with a solution to the parking brake, as 1st in low range is about as good.

[ebinmaine 74,031]

1 hour ago, Racinbob said:

it's possible to change an entire 8 speed for a 6 speed with nothing more than some simple linkage changes.

 

I believe that's true. 

 

I've had a 12?7 here in the past that was changed to a 8 by a PO. 

 

I gave up on that because of the linkage and EATING belts. 

But I digress.....

 

 

 

6 hours ago, oliver2-44 said:

anyone have a way to compare the 2 cases,

 

I could do that Saturday. 

I have a 6 speed disassembled on the shelf. 

Maybe an 8 too but that could happen anyway.