87' Burban rear axle info

[Stumpy]

Just signed on as a member today! I am trying to figure out how to post a
question concerning gear/ratio on my 87' 1/2 ton Suburban. Will there be
issues in pulling the rear end out of my 87' Automatic 4x4 Suburban (350) and replacing it with the reae end of a GMC Jimmy (specs same as mine). Where on the vehicles can I find information on axle gear ratio???

 

[dontoe]

If it's a two wheel drive, then there's really nothing to worry about gear ratio wise.........only thing is the speedometer will be a bit off.

 

[resurrected_jimmy]

100% way is to pull the cover and look on the ring gear. there will be a bunch of numbers followed by something like 11 41.... this is the number of teeth on the ring gear and pinion 41/11= 3.73

On your truck, if the RPO sticker is still inside the glove box it will have a bunch of codes on it, GT4= 3.73, GT5= 4.10 and if it doesn't say either of these its probably a 3.08 or 3.42 ratio.

 

[jonrpick]

If it's a two wheel drive, then there's really nothing to worry about gear ratio wise.........only thing is the speedometer will be a bit off.

Won't a 2WD axle have 5 lugs instead of 6 if it's a 1/2-ton model???

 

[resurrected_jimmy]

yes it will, however shafts are interchangeable

 

[Stumpy]

Just got home from work --- The RPO stickers you speak of are in the glove box (bunch of 3 digit codes). I'm gonna try and get a picture off of both vehicles -- see if you can make sense of it. Thanks!

Is there a way to attach pics to the post???

 

[resurrected_jimmy]

your burb has 3.73 gears with a limited slip differential (3rd column, 3rd code down... GT4=3.73, G80 right next to it is limited slip diff)

the donor truck appears to be a 3.08 gear open diff

 

[Stumpy]

Well I guess the donor is a no go. I tried to open the attachents you sent back and I guess I don't have the abillity/access to that either (not being a member). Is one axle better than other (ie:4.10 vs 3.08)? Do you think it is wise to replace the gears or simply find a used rear end some where?

 

[resurrected_jimmy]

In something as heavy as a burb I wouldn't want anything less than 3.73 gears or its gonna be a real dog and put a lot of stress on the transmission. Finding a 3.73 axle to replace yours with ought to be fairly easy. Many trucks came with these gears. Before you give up on the donor jimmy, pull the rear cover and get the numbers off the edge of the ring gear to be certain what ratio it has.