differential madness!

[Section8]

Ok. How do I find out the inside and outside diameters of my ring and pinion in my axles. I know they are geared 6.17!!!!! I can't find anything on the net to get the actual specs on the sizes of them and the carrier. The tech manual on the site is either down or to larger for me to download.
I am also aware that the axles are more than likely 27 spline or the of chance 10.
The diff covers have ten bolts so do I measure the rings and such as a standard 10 bolt axle??
If any one has taken apart their differentials on their M135 or have the required info could you please let me know!!
Closest thing I can come to is H110 for a part number.

 

[ODdave]

Dose section 8 mean the same thing in canada as it dose here?

 

[Gunfreak25]

You are correct on the H110 designation. The general consensus is these are made by Eaton. They were made from 1946 to about the mid 80's, and were put on many GM medium duty vehicles. The ring gear is 12.25", axle shafts are 1.75" with a 27 spline count. The most common gears were 6.17 and 7.20, 5.43's are very difficult to find. These all feature a load bolt on the ring gear to prevent it from flexing and loosing engagement under the most severe loading conditions. It's pretty crazy stuff. The cast iron differential cover is Military specific, most civilian axles have the plain round bolt on cover or even a welded on cover. Detroit makes lockers (250S-27) but they are extremely expensive.

 

[Section8]

That's awesome!! I could find most of the other info but the actual ring diameter! Thanks Gunfreak25!!!
I have sourced a dealer who I believe is based in the states who sells all sizes of those rings.
Section8 is in reference to the tv series *MASH*.
Which is where I fell in love with seeing deuces!

 

[m1010plowboy]

It's Canada, and Section8 does mean Section8.

More references on this page Section8.

MilitaryTrucks.ca Website - M135

 

[nattieleather]

To civilians in the US, Section 8 is government subsidised housing. In the military it means that Klinger was trying to prove he was crazy so he could get out of the Army.

Good job on the info hunt there Gun! I had always figured that the diffs had to have been used on civy trucks also.

 

[Gunfreak25]

This amount of work required to swap ring/pinions is substantial. Unless you like wrestling 200lb hunks of iron underneath the truck where you have no place to lift stuff, I would just go with 46" Michelin tires. If you shop around you can get the XML 395's for under $200 a piece. So you figure roughly $1500 for a whole swap. It's easier than swapping other things like ring gears and transmissions, engines and the wow factor with such huge tires is really neat. If my numbers are correct, 46" tires will reduce engine speed by over 400-450rpm over 9.00 tires. That is a pretty significant drop, offroad-ability will increase and braking power will hardly be affected thanks to the GMC's 12 wheel cylinders. 46" is the largest you can do, you can use your stock rim/tubes and in the case of these GMC's, you can run the rears "dish out" like all the 5 ton guys do.

 

[Section8]

I have 11.oox20's on my rig at the moment. 395's wont fit on the stock rims since they are only 7.5 inches. 395/85/20r's are a mininmum of 10 inch rim width for mounting. I wish i could get 395's for 200 bucks!! Up here in canada the cheapest I can find them for is 400 to 500. Five hundrend or more if new!
Then i would have to find some hemmt rims with the gmc 6 bolt pattern which are impossible!! Custom rims start at 550 and up from what i can find on the net and that is out of the states. so add shipping and customs hassles!!
Sooooo! swapping diffs or tires and rims! Either way it is costly.