I have a 1977 Ford F-250 high boy. It is not a daily driver, but it is very reliable. I use the truck for hunting, hauling heavy fire wood loads, pulling the camp trailer up on the mountain. Probably 50/50 paved road, mountain dirt road driving. I am looking at a detroit, grizzly or spartan locker in the rear end. What are your thoughts with how I use my truck? My main concern is automatic pulling with a locker.

 

I wouldn't use any mechanical locker in your truck. Dana Power Lock is imo the best clutch style limited slip ever made for rear or front and is exactly what your looking for.

 

I decided to go with a spartan locker so we will see how I like it. I have a truetrac in the front that seems to work decent off road.

 

This maybe a little "off topic", but I thought I'd try. I am usually on the van side of things.I have an 02 Quigley E350. It has a dana 60 LS in the rear. Thoughts about a LS in the front dana 60? I have heard good and bad about it. Steering on ice and snow??? Any opinions?

 

LS in the front would cause no problems. If your in 4x4 you will have no problems with sliding around.

 

A buddy just put a true Trac in his Jeep XJ rear (Chrysler 8.25). Why didn’t you just do that for the rear? Why the true trac in front and spartan locker in rear? Did you just desire a true locker for rear?

I have never used a locker, but know my buddies 2017 SD was a handful on slippery surface with rear axle locked. Appreciate your insight!

 

I did not go with the truetrac LS in the rear because from my experience they don’t work very well when you really need them to. My front LS does not work when I have a front tire lifted off the ground, and seems to only work half the time I’m loosing traction going up a steep hill. Granted my front LS is fifteen plus years old.

The three vehicles I have had an auto rear locker in it has not been a problem. Two of the vehicles were 3/4 ton pickups, and one was a Toyota Tacoma, all had manual transmissions. The auto rear locker was a lot more noticeable in the lighter tacoma. The detroit locker I had in the 72 Chevy was not noticeable at all on the street unless you hit the gas going around a corner, and was always there when you needed it off road. The spartan I have in my ford highboy behaves really well on road. I here the click when I go around corners and feel it trying to engage when I am coasting around corners with the clutch pressed in. It has been great off-road just like the detroit so far. Snowy and wet roads has not been a problem for me. I have not hit any black ice that I know of at freeway speeds yet. If it is a really snowy/icy road I am usually in 4 wheel drive. I don’t think a rear auto locker is a detriment to a vehicle that sees a lot of pavement.

 

Very good info, thank you!

 

The Tru-trac is actually an open differential with helical gears that apply torque multiplication from the side with less traction to the side with traction. If one side has no traction at all, it will spin like any other open differential.

The typical clutch type LSD have preload springs that lightly apply pressure on the clutches all the time so that if one wheel completely loses traction, the other side still gets a little bit. That's usually enough to allow the side load of the pinion gears to press on the clutches harder to try to lock up both side.

If you're doing mostly off-road driving, the rear locker is the way to go, and you will prefer a clutch type diff on the front.