4.11 Gears - Rear end

[exploderjim]

Where would be the best place for cost and value to get 4.11 gears and posi carrier with axles and master install kit including bearings for my rear end? I'm putting in a 6.0L LS2 with a 4L70E and it used the 4.11's. So I thought I would put them in my 2wd Blazer to go with the original set up of the transplant. Any advice would be appreciated. Also would the original 3.73 be to low a gear to run with that engine tranny combo?

[69GWC]

I bought a master install kit, new ring and pinion and a TrueTrac locker from Summit for my 69.
Posted via Mobile Device

[RWB-713]

Originally Posted by exploderjim

Where would be the best place for cost and value to get 4.11 gears and posi carrier with axles and master install kit including bearings for my rear end? I'm putting in a 6.0L LS2 with a 4L70E and it used the 4.11's. So I thought I would put them in my 2wd Blazer to go with the original set up of the transplant. Any advice would be appreciated. Also would the original 3.73 be to low a gear to run with that engine tranny combo?

If you're wanting this thing to be a daily driver and someting you can crusie around and get decent fuel economy with, I'd stick with the 3.73's really. That is a deep enough gear to give it plenty of pep off the bottom, but keeps your RPM's down at crusing speeds. 3.55-ish be even better I think. Unless your just wanting to burn tires off all the time and/or slick it up and take it to the strip (which is fine, your project!), i'd stay with something higher than a 4.11 for sure.

[exploderjim]

The only reason for the 4.11's is that was the rearend gear out of the donor truck. So the rpm's at highway speed were only 2200. I thought if I went to 3.73 it may drop that even lower and be shifting all the time. Any thoughts?

[exploderjim]

Actualy you may be right. I check Richmond gear and at 70mph it would run 2100. Does it matter that it has a 3200 stall in it as well?

[RWB-713]

Originally Posted by exploderjim

Actualy you may be right. I check Richmond gear and at 70mph it would run 2100. Does it matter that it has a 3200 stall in it as well?

Once again, depends on what you want to do with it. 3200 is WAY high for something you don't plan to be drag racing.

And as far as it shifting all the time, if you're crusing down the highway in a light-load, part-throttle situation, that tranny is gonna be in OD, it will down shift when you apply more throttle, or the load increases. That's how it's meant to work at least.

[piecesparts]

With an OD tranny, the 3.73 will give you good low end grunt and the Highway RPMs will not be too bad. It depends a whole lot on the tire diameter that you choose. The 4.11 gear is a really low end gear and would be good for pulling logs out of a hole, but daily driving at the prices for gas, in this environment, would give you a lot of grief. My truck has 3.73 fears with a 700 R4 tranny (However it is without the lockup converter). I run about 2500 RPM at 75 MPH, with a 28" tall tire. A taller tire would make it a lot lower in RPMs, but I also have a 2300 stall converter and I want to keep my tranny in an RPM range that has the converter engaged. It is important to consider keeping whatever engine combination you choose in the optimum power range for operation. If you have one that is fuel injected, the computer will work that out for you.

[trac209]

I'd stick with the 373s. Don't forget how tall where the tires on the donor truck to what you're going to run.
Posted via Mobile Device

[exploderjim]

The old one had 20's and the new one is run 22's but virtualy the diameter.

[1970 C10 MJW]

i would make a suggestion that you put this post in the LSx swap section... the ls engines are a lot differnt, that being said I am working on a swap myself... I would say 3.73s would be fine, and do you have a cam intake and heads? or what is the reason for the stall? if its a stock engine the stall isnt really necessary, for instance I am going to be running a ls6 intake, 799 heads, f14 cam, fbody long tubes, and cai, and i will have a 3400-3600 stall, which is what my buddy has in his camaro, and it still locks up below 3600 if hes not at WOT and above 40 mph

[exploderjim]

Yes it has a cam, intake, rods, springs, kooks 1 7/8 headers with cats, electric fans, under drive pulley, built tranny with hardened shafts and vette servos, tune, EFI ...etc. it put done 448hp at the wheels of an awd truck and ran a 12.9. It did drive nicely at highway speeds around 2500 rpm at 75 mph. Just wanted to make sure the 3.73 would be up for the task.

[exploderjim]

I will try the LSX section as well.

[trac209]

If it made 448 at the wheels 373 will be fine. Truck will or should be lighter than a awd new truck and should fly with the 373 just fine.
Posted via Mobile Device

[exploderjim]

Thank you for the advice much appreciated. I'll start with just redoing the 3:73 and all new seals and bearings. Actually could use a lead on a set of new axles for the sake of good order.
Posted via Mobile Device