4.56 or 4.88 thick gears

[01mudslinger]

i have a 10 bolt front, lockrite, chromoly's, warn hubs and a 12bolt rear welded with 38's and 3.08 gears in a 88 GMC Jimmy with 350 and 700R4.

I was wanting to go to a 4.56 but after reading im thinking maybe i should go lower since my ride is trails only. Im having a hard time finding the part #'s and understanding the thick gear thing. I can put a lower gear in my carrier without having to change it right? Could somebody please send my in the right direction and maybe some part #'s if you happen to know em. Thanks for your help.

 

[01mudslinger]

anybody?

 

[6.2Blazer]

If you have stock 3.08's and want to re-use the existing carriers/diffs, you will need the following:
- rear 12-bolt - requires thick cut gears for 4.56 or 4.88
- front 10-bolt - does NOT require thick cut gears for either 4.56 or 4.88

Different makes/models of axles have different carrier breaks. A site like Randy's Ring & Pinion contains some pretty good info (www.ring-pinion.com) and explains this.

With 38's and the 700r4 I would probably go with the 4.88's, though there is only a small difference between 4.88 and 4.56 and either would be a huge improvement/difference compared to the 3.08's you currently have.

I will guess that somebody will bring up the topic of using a 12B/10B combo with 38's and 4.88's.........

 

[Stomis]

If its trail only go as low as you can. Again as mentioned your putting more stress on the running gear. I would be worried about that 12b first... Perhaps a good route to go would be to find a cucv 14b that locked a 4.56's and 8 lug and regear the 10bolt to match?

 

[01mudslinger]

thanks for the explanation guys, so all i gotta do is just order 4.88's for a 8.5 10 bolt and im good to go and make sure the ones for the 12 bolt are thick cut. yea im pretty comfortable with the front 10 bolt, i was breaking axles until i got the chromoly's and changed my driving a little bit, now it seems to be good, i will probably got some chromoly's for the 12 bolt also and that should keep me goin good.

 

[Kyle89K5]

i have a 10 bolt front, lockrite, chromoly's, warn hubs and a 12bolt rear welded with 38's and 3.08 gears in a 88 GMC Jimmy with 350 and 700R4.

I was wanting to go to a 4.56 but after reading im thinking maybe i should go lower since my ride is trails only. Im having a hard time finding the part #'s and understanding the thick gear thing. I can put a lower gear in my carrier without having to change it right? Could somebody please send my in the right direction and maybe some part #'s if you happen to know em. Thanks for your help.

Part numbers, I got nothing, but I can say, I've got 4.56 gears with a 700R and 36's. I wish I had 4.88's. When I goto 40's, I'll be going min. 5.13's I like a little extra RPM on the highway. With your 38's, I'd go 4.88 easy, maybe even lower...