That & some good traction contol , you don't want the rear to move around . Lew

 

What Lew said. But if you're going to lock the rear, make it a selectable locker. I'm waiting on the day I hear BLAM!!!!!!! from my rear end from taking a corner too hard and too fast just to survive traffic. (I have an automatic locking diff)

 

Ew, selectable lockers.

Go detroit or go home.

 

What's wrong with selectable lockers? I would rather be able to pick and choose when to lock my rear than run around like I am now. Besides, running around with a locked axle is hard to control on wet concrete and Ice. These situations an open diff is better.

 

Many years ago farmers would take old trucks and install or adapt tractor gear housings on the chassis. In 1971 I helped haul out a Model A that had been transformed during WW2 and was used until the 1960s. We actually got the thing running and the owners used it for hay rides and to move stuff around the yard. It had an aux trans mounted on the rear of the original gear box and @ 2 mph hauled out a IH tractor and combine after the "cornbinders" injector pump let go.
I think the engine was the 122 CID flat four which was an improved Model T engine with a Frontenac high performance kit. The Model A might have been a police car at one time since the kit was used by many police departments.
old man rambling
sorry
rikard

 

That's true, but selectables tend to be a lot less reliable than a detroit or even a powertrax.

 

Gear reduction would be limited by the strength of the drive axle.

When in transfercase low,first gear and 4.10 axle ratio with the 302 at torque peak-there is about 11702 foot pounds of torque at the rear axle. Offroad conditions-such as one good jerk of the throttle or getting a drive axle into the air could cause very expensive axle damage-even in a factory equipped truck such as my own.

270 ( @ 2400 RPM torque peak 302 ) x 2.69 (low range) x 3.93 (first gear M5R2) x 4.10 (8.8 4.10 axle ratio) = 11,702.871 foot pounds.

43.34 to one gear reduction overall .

 

Really? I would think picking when to lock the rear diff would prove to be more realiable than having an automatic locking diff just because you know it's locked and therfore you're not going to take a 90o turn going ten mph.
With that said, I try to be careful when I make a turn, but sometimes I have to floor it at an angle. So far all it's done is bark the tires and jerk the truck (minor jerk, but you feel it).

Hard to believe nobody makes a realiable selectable locker though?

 

Eaton detriot true trac... Cant beat them.. No clutchs, hook good ,4x4 or 2x4, off road or on the strip .. Lew

 

problem when going past 4:56 gearing is the pinon gear becomes so small its comical, then it becomes the weak point. lowest i seen on a normal driven 8.8 was 5:13 and it held up OK.