Gmt900 Rear Gear Upgrade Help Needed!

[Zembonez]

I want to get rid of my crappy 3.23 gears and go with 3.73s. I've been looking at Summitracing.com and Jegs.com so far but don't really have enough details to know what to buy. I have a buddy at a local shop that builds a lot of trick drag cars that can do the set up and install. He says "show up with the parts and beer and we'll get it done". He builds a lot of trick fabricated 9 inch stuff, so I am quite certain that he has the skills to set it up right.

 

I do not care about GM warranty.

 

What kind of rear axle is this and how do I know what size ring and pinion to get? Obviously it is a 10 bolt variety and I do not have a locker. Any fluid recommendations?

 

Edit: Here's a pic.

 

[merlin5577]

8.5 inch 10-bolt. Should be pretty much remove and replace. If your going to spend the time to replace the gears I would suggest adding a eaton posi while your in there.

 

Royal Purple Synthetic 75w-90

[Zembonez]

8.5 inch 10-bolt. Should be pretty much remove and replace. If your going to spend the time to replace the gears I would suggest adding a eaton posi while your in there.

 

Royal Purple Synthetic 75w-90

Is it safe to assume that the aftermarket setups from Richmond and the like will work in the GMT900 rear end?

 

I just found a set of headers that I want too.

[merlin5577]

8.5 inch 10-bolt. Should be pretty much remove and replace. If your going to spend the time to replace the gears I would suggest adding a eaton posi while your in there.

 

Royal Purple Synthetic 75w-90

Is it safe to assume that the aftermarket setups from Richmond and the like will work in the GMT900 rear end?

 

I just found a set of headers that I want too.

 

 

Yes. Dont go with a no name brand (machining tolerence differences) but Richmond makes some good stuff.

 

Headers? Headers are good!

[Darkanion]

I just found a set of headers that I want too.

Shorties, mids, or long-tubes?

[JoshRDavis.84]

8.5 inch 10-bolt. Should be pretty much remove and replace. If your going to spend the time to replace the gears I would suggest adding a eaton posi while your in there.

 

Royal Purple Synthetic 75w-90

Is it safe to assume that the aftermarket setups from Richmond and the like will work in the GMT900 rear end?

 

I just found a set of headers that I want too.

 

 

 

Sounds like some good upgrades!!!

[Zembonez]

I just found a set of headers that I want too.

Shorties, mids, or long-tubes?

 

Shorties unless I want to replace the Y and cats (rather not) I think the headers with a magnaflow will do what I want. I'm tired of Daddy making fun of my STOCK exhaust! I wanted to find a winter hotrod project, but instead I've decided to make my truck the project.

 

3.73s with a locker and the exhaust are first. Once that's done I'd like to look at blowers... We'll see.

[Darkanion]

Shorties unless I want to replace the Y and cats (rather not) I think the headers with a magnaflow will do what I want. I'm tired of Daddy making fun of my STOCK exhaust! I wanted to find a winter hotrod project, but instead I've decided to make my truck the project.

 

3.73s with a locker and the exhaust are first. Once that's done I'd like to look at blowers... We'll see.

I've "heard" that there isn't much of an advantage with shorties vs. the stock manifolds. Supposedly, the stock manifolds were designed pretty well. I've been told a few times to not even mess with shorties. "Go at least mid's, but preferrably long-tubes, if you're going to put headers on a GMT-900 truck," is what I've been told by a few people. Maybe that pertains more to the 6.2's than the other engines, though...?

 

I've priced long-tubes... and that'll be a while for me (like after the truck is paid for and I have something else for a daily driver). They're too rich for my blood.. at least for now.

[2000DV4.8]

3.73s with a locker and the exhaust are first. Once that's done I'd like to look at swapping in a 6.0... We'll see.

 

Fixed that for ya.

[Zembonez]

I've "heard" that there isn't much of an advantage with shorties vs. the stock manifolds.

Very possible. I'm being told that the shorties will work very well with boost. I'm with you on the fact that they won't make a ton of difference otherwise. I don't want to get into the whole "redesigning of the O2 locations and adding new cats" that long tubes will create. I'm going to do some more research but it won't take as long as choosing black wheels.

 

What STARTED all of this was my DISMAL 1/4 MILE RUN on Friday. Holy pajeebers crap! My truck is slow. My time was terrible.

 

I'm gonna fix that. Just watch.

3.73s with a locker and the exhaust are first. Once that's done I'd like to look at swapping in a 6.0... We'll see.

 

Fixed that for ya.

 

I know you are joking but I would not even consider a 6.0 unless I was building from scratch. I like the idea of stuffing the 4.8. Same architecture... only difference is bore and stroke. I like smaller displacement engines running boost. The power is less "peaky" and more linear... plus it would be FUN to tell people that they got spanked by a 4.8

[2000DV4.8]

Ok, now you NEED to tell us what you 1/4 mile time was...

[Zembonez]

Ok, now you NEED to tell us what you 1/4 mile time was...

16.210 @87.05

 

Pathetic.

[tobias]

You're going to lose your GM warranty.

[2000DV4.8]

Ok, now you NEED to tell us what you 1/4 mile time was...

16.210 @87.05

 

Pathetic.

 

 

OUCH! I'd HATE to see what my truck runs, 4wd, ext cab, and 173k on my 4.8.

 

Your 20s probably weren't helping you out any, or did you put stock wheels back on?

 

EDIT: Did you leave the cap on too?

[Zembonez]

OUCH! I'd HATE to see what my truck runs, 4wd, ext cab, and 173k on my 4.8.

Your 20s probably weren't helping you out any, or did you put stock wheels back on?

EDIT: Did you leave the cap on too?

I ran it just like it looks in my sig. I wanted to get a base line for performance so I can see what my new mods do to it. I didn't expect miracles, but I was hoping for a higher trap speed. I shouldn't complain with the crappy gears I have. It should be pretty easy to get it down around 15 flat. We'll see!

 

Edit: Torque management KILLS the truck off of the line. No matter how hard you try to launch it interrupts the process. Obviously, I'll want to tune that out once I make a little more power.