gears

[trx88]

wanting to finally order gears and master kit

got 35's on my 96

wanting 4.88 and wondering is that too deep cause ive heard 4.56 is perfect

i wanted 4.88 cause i wanna go up an inch or so or be able to haul good

will i regret 4.88?

also would a standard 14 bolt sf axle with 3.73 gears have an axle break?
need i order the thick or standard 9.5 ring


one more thing do i have to get a core axle that had posi to put a locker in it or can i start with an open core..

 

[90'rado]

.....

 

[dirtridinz71]

I wish I had gone with 4.88's instead of 4.56 on my 92 with 35's, but I hardly ever see highway use.

There are no axle breaks in the 14b sf, so there are no thick cut gears.

As for the locker, I have an open carrier with a lockrite (lunchbox locker) in it. Was looking at a Detroit, which would replace the carrier or G80, but I had the open carrier laying around.

 

[trx88]

i thought there was a 14 bolt sf 9.5 break in 97

i got mine from a 96 just the other day actually..

im taking pictures of the build also

actually 4.56 would be better on the highway than 4.88

the final drive ratio for 4l60e is .70 there is a formula

it works out to be a 35 inch tire with a .70 final drive and 4.56 makes 1990rpm at 65mph
the 4.88 is more like 2100rpm with the 35 and 65mph, i have the formula written down but dont have my little notebook right now.

i know they ask you for pre or post 97 info when ordering the master install

but whats this i hear about a thick ring

 

[88GMCtruck]

There is no carrier breaks on a 14SF. I'm not sure why they want to know what year the axle is, from what I know they are the same in every GMT400 truck.

Thick ring gears are for putting on carriers designed for smaller gears.

I'm actually in the process of installing a set of 4.56 gears in my 14SF. I decided against 4.88s since my truck is lighter and I have a manual trans.

 

[1990GMCSIERRA]

if ur planning on any highway use id stick with 456s

 

[trx88]

only thinking 4.88 would help tow the jon boat or camper for deer season

and if i ever wanted to put taller tires on there

 

[99z28monster]

only thinking 4.88 would help tow the jon boat or camper for deer season

and if i ever wanted to put taller tires on there

Well if you plan on taller tires I would say go for it. Other wise 4.56 will be just fine for towing trailers or hauling a boat. If you need lower gears for the towing reason I would look into a healthier engine.

 

[1990GMCSIERRA]

and trans

 

[98chevy4x4]

Can you figure out what my truck would run with 4:10s and the rpms with that formula cause thats what im wanting and sometime i get on the interstate