What rear diff do I have?

[budman k20]

Help!

I went to the parts store today to try and buy seals and cover gasket. Without knowing what type of rear end my truck has it seems there are two choices Dana or GM. Can someone tell me what rear end my truck has...without pictures! It is a 72 K 20 (3/4 ton 4wd) and the rear has a removable 3rd member or center section and also has a removable rear cover that is round. 8 lug floating bearing axle on leaf springs

[Rack Man]

Here...check out this ID Chart....

http://www.coloradok5.com/axleguide.shtml

[Cyclone]

GM (eaton)

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Heres a Dana cover for referance:

[budman k20]

Wow,

Thanks for the quick reply guys. From looks I must have the GM (Eaton) rear. Is that normal for 3/4 ton trucks? Is it called a 10 bolt? The parts guy asked and I assumed a 3/4 would have 12 or more?

[Cyclone]

Eaton is most common/normal for 3/4.Its not a 10 or 12 bolt, its an Eaton.

[sweet70beast]

I believe in 72 and earlier 3/4 ton the eaton is the only axle that came in 4x4s. 2wds could have either one depending weither it was coil or leaf. I am by no means an expert but all the coil spring 3/4 tons I have seen have the eaton and all the leaf 3/4 tons have had the dana.

[1969 GMC]

Originally Posted by sweet70beast

I believe in 72 and earlier 3/4 ton the eaton is the only axle that came in 4x4s. 2wds could have either one depending weither it was coil or leaf. I am by no means an expert but all the coil spring 3/4 tons I have seen have the eaton and all the leaf 3/4 tons have had the dana.

My '69 GMC K2500 came stock with a D44 front and D60 rear, 4.10's. It's also interesting to note that the D60 rear that was under this truck had 30 spline axleshafts...fords and dodges of the same vintage seem to have the coarser splines.

[sweet70beast]

I saw a neighbors 67 K20 today and sure enough it has a dana 60 rear. Learn something new everyday.

[72-c20]

specifically, it's an Eaton H052 rear end. I got my pinion seal for mine at NAPA...

[Elephanthead]

Is that bolt on the Eaton H52 cover where you fill the gear oil up too?

[budman k20]

Yes it is...

[CPNEJR]

typically 3/4 ton 2wd and 4wd chevy's had an Eaton HO52. GMC's had a Dana 60. my dads 72 GMC K2500 has a Dana and my 70 and 72 K20's have the Eaton. the Eaton parts can be harder to find also.

[Dooley]

My 1972 1ton 8.5' longbed 2wd GMC had the leaf spring Eaton rearend.

[mothertrucker424]

were are parts avalible for the eaton rearend and how can i upgrade it and any good write ups?

[1969 GMC]

Originally Posted by mothertrucker424

were are parts avalible for the eaton rearend and how can i upgrade it and any good write ups?

there are not many aftermarket products for them, the only one I can think of off the top of my head are disc brake brackets.

however they are fairly beefy. I have never seen or heard of a broken one. The No-Spin (Detroit locker) is now discontinued for the application, however a 14 bolt diff will swap into the Eaton's carrier, provided you switch to 14 bolt axle shafts. there are a number of lockers or minispools available for the 14 bolt, and these will swap into the eaton.

there were aftermarket gears being sold in 3.90 and 4.11 and perhaps some other ratios, but i don't believe they are available any longer. All bearings in the center section and the wheel bearings are on the shelf type parts at the parts store. some of the brake hardware may be hard to find, but there are always disc brake conversions.

eatons are a bit lighter than 14 bolts also due to the sheetmetal axlehousing, which can be a good thing.

if you search, there is plenty of information here on these rearends. you don't have to throw it away just yet.