rearends-drum to drum

[wade-ve7trw]

what is the difference between a rearend from a mid 80's 1/2 ton and one from a 96 c1500 1/2 ton:confused: Cannot get a definite answer from the dealer or junkyards. They want anywhere from 650 to 1700 cdn for a 96's rearend and 250 to 500 cdn for a mid 80's rearend:confused:

[crashz]

There can be many differences depending on the year of the 10 bolt rear axle but some differences can include:

-axles splines (which also changes axle shaft diameter) and corresponding carrier & spider gears
-brakes
-spring pad location
-and I think a 96 has the speed sensor on the ring gear.

Obviously this does not account for the obvious gear ratio issue, but thats a given. I believe GM also made the track width of the 10 bolt wider, but don't remember the year. 2wd and 4wd had different hub bolt patterns. Also can't remember if they changed the axle tube size.

[wade-ve7trw]

I should clarify--I exploded the rearend in my 96 1500 and the only parts that are reusable are the inspection plate bolts (10 of them). What I am planning is a complete drum to drum swap. There is no speed senders in mine. ABS can be changed over with backing plates. Spring hanger and shock mounts can be moved with a hot wrench. I have three options at this point. Pay an insane price for a 96 rearend. Find out the differences in a mid 80's and 96. Or pick up a rearend from a 99 1/2 ton which needs a little work and end up with disc brakes and a few more mods to the braking system. So at this time I am trying to find out what the differences are between the various years. All Help will be gladly accepted. There is fourth option also:D--Pull motor--scrap the rest and drop the 6.5TD into an older truck with no computer and start from there:D

[Hubert]

Might look at pirate 4x4 dot com. They have a good write up on the 14 bolt rear end. I can't remember if they have the 10 and 12 bolt rear end but the 14 bolt write up gives a very good summary of different models. Year changes OAW, spring hanger point width, etc etc.

[More Power]

I have a good 3.42 geared with limited slip 10-bolt 1/2-ton rear axle assembly for the 90's body style (GMT-400) that you can have - no cost..... I'll help load it... But, it's in Montana..... ;)

Jim

[crashz]

I see your point. It sucks to pay more for essentially the same axle.

Double check in the housing and see if there is a tone ring sandwiched between the ring gear and the carrier. This is what I was refering to as a speed sensor and is used for the ABS. These are not on the older 80's models and modifying to fit could be more trouble than its worth.

I'll echo Huberts recommnedation too. If you really destroyed the 10 bolt, another 10 bolt will probably grenade just as fast. What about swapping in the semi-floating corporate 14 bolt that was used on certain model 1/2 tons and light 3/4 tons in the GMT 400 platform? Better axle and easier swap.

[wade-ve7trw]

perhaps the history of the truck is in order.
The truck was bought to be used as a daily driver while i did the work on my 79 dually. The truck has 330k on it but new motor put in with about 100k on it. I have a feeling that the rearend have been weakened from before i got it. Reasons Why: there are holes in the box that look like a fifth wheel hitch was installed on the unit and overload springs( first owner); and the box has a bad dent just behind the passengers rear wheel well made by a disagreement with a fork lift in the lumber yard; also the fact that i know the driving habits of the past owner that i bought the truck from( i have to work with him sometimes). Overall the unit is in not bad shape. When i bought it i changed all fluids - but did not remove rear cover - sucked out rearend fluid with vacuum-no metal in analyzes. Looking at remains of carrier there are evidence of old cracks in it( discolored surfaces).
as for the abs tone ring on it i will look. should be easy to put it on a new used rearend since i found one at a reasonable price from a 85 1/2 ton. Will have to take apart and move mounts to mate up to the 96 parts. The only problem i see is that the new ratio is 2.73. I wonder what that will do to the fuel mileage of the truck-I'm getting about 22mpg now.