What axle?

[tmoreau]

Can anybody tell me what axle my truck has or how I can identify it? Its a 2001 1/2 ton 2wd with a 3.08 gear. I want to gear it down but I dont know what axle it is to shop for a ratio (10 bolt, 14 bolt, 8-1/2 inch 10 inch... ???? very confusing) Thanks.

[LS1 ZR2]

You have a 8.625" 10 bolt in your truck. It takes the same ring and pinion as the late model GM 8.5" 10 bolt does.

[todddd41]

But will the 8.5 posi units fit? And how many splines?

 

Thanks!

[tmoreau]

Thanks, I second the question about posi since if I change the gear I will be adding either a posi or some type of locker. I think I would have to give in to reason and either make it posi or a selectable locker for street use, snow and a reg. locker is a little more fun that I think I want to have.

[LS1 ZR2]

This truck would have 30 spline axles, as do all full size late model 1/2 ton GM trucks. You can use a 8.5" carrier (posi or standard), but you will need special side bearings. The difference between a 8.5" and a 8.625" is the bearing size on the carrier, and the outside dimension of the side bearing race. The bearings are larger on a 8.625. Either carrier can be swaped into either axle, as long as you have the correct bearings and races. They are available at most axle part suppliers.

[JayMan]

If you want some sort of locking rear end, PowerTrax makes the NoSlip. It's fairly easy for a DYI to install, is all mechanical so no friction-modifiers needed, and should last a long time. The part number is:

 

92-0786-3005

 

http://www.powertrax.com

 

I would double-check with PowerTrax to see if there have been any part number changes, as that part number is almost 4 years old. I've always had an easy time contacting PowerTrax, which is now part of Richmond Gear.

 

Any reason you need/want a lower gear? With a V6 and 5spd, you can't do any heavy towing anyway. Factory special order goes to 3.73, so it should be available.

[tmoreau]

I certainly dont make a habbit of it but I have pulled over 5k lbs before. 250 miles, no sweat at all, kept it in fourth and lower speeds acordingly and still got 14mpg. I often pull 2k lb trailers and you really never have any idea they are there. Keep in mind this engine makes 265 ft-lbs of torque at around 2400 rpm which is only a hair behind the 4.8 with 285 which dosent peak until 4800 rpm or so.

 

The 3.08 is just too dang tall, this truck moves fairly well but a lower gear would give me a little nicer acceleration and would also allow me to run fifth on 55mph backroads. Currently I cant drop it in fifth until im going 60mph unless the road is completely flat and traffic isnt slowing down every few seconds, then I can hold it at around 55 but any less is fourth gear teritory. At 80 mph I am turning an even 2k rpm, I can obviously get away with a little lower gear. A 3.56 ratio would be ideal for me but I am limited to 3.42 and 3.73, I think if I do it I will go with 3.73 cause I like the sportiness of it and I would still only be turning 2400 rpm at 80mph.

 

This starts getting pretty expensive though so I have thought about just picking up a lockright or similar DIY lunchbox locker and calling it done. So many options..... so little money.....

[JayMan]

Sounds like you want to go with the PowerTrax NoSlip then, as it is easy to install. The NoSlip is about the easiest mechanical locker to live with.

 

Didn't realize you were towing so much. At over 5000 lbs you do realize you're exceeding the rating for your powertrain? GM recommends no more than 5000 lbs for the Vortec V6, 5spd, and 3.42 gears. Should be okay with 2000 lbs though, just easy with the clutch.

 

Anytime you get involved in changing the ring/pinion, that can get expensive if you can't do it yourself. I've always found setting the backlash a tricky and time consuming proposition.

 

If you have to pay somebody, count on about $1000 for the new ring/pinion with backlash properly set, and the NoSlip installed.

 

Your mileage may vary.

 

Are there any qualified machine shops in your area that do this sort of work?

[tmoreau]

Ah yes, the powertrax no-slip does look like a great choice for me. As much as I would like to change the gear I am again talking myself out of it due to the expense. I just dont think it would be worth it. I only pulled that kind of weight once, I bought a jeep out of state and had to tow it home. 1981 cj7 v8 plus trailer and a whole bed full of parts such as leaf springs, hoods, and other heavy parts. No doubt I could feel the weight but aside from wear on the clutch I dont think it is a big deal to pull that. Normally I never pull anything over 2000lbs though so its not a big deal. I will have to give some more thought to the no-slip, thanks for the info.