Any advice on which ones, I have an open rear and it sucks I am always haveing to use four wheel drive. What about a lift kit or leveling kit where would I find one?
Thanks Heath

 

If your '91 is like my '93, then you have and oddball D70. most D70's have 1.5" 35 spline axles. Ours has 1.3"? 32 spline axles. Tractech makes a 32 spline Detroit locker, its about $600. I'm not sure about any others.

 

Like VueDoo said check the spline count first. A Detroit will definately solve the traction problems and they are durable but some people don't like the way they handle on the street. If you have or are willing to upgrade to 35 spline an ARB air locker gives the best of both worlds. It handles perfectly on the street and on slick streets(Detroits not so much so) then it turns into a full spool when engaged. I also would wonder how a Detroit would act while towing. Biggest down side to an ARB is more $$ and more complicated. In my Ramcharger trail truck with Dana60 front Dana 70 rear I run ARB front Detroit rear just for reference.

 

Is there anyway that is quick and easy to check the spline count with out taking the cover off?
Flake do you mean that the detorit will not do very well on slick roads?
Heath

 

A locker style diff does make the handling a little trickier on slick roads because both tires break loose at once. A posi/limited slip is a about the same. With an open diff, one tire spins but the other just keeps rolling along, keeping you from going sideways as long as you don't get too stupid with the gas pedal. You just have to be more careful with a locker or posi when applying power and turning so as not to loop the truck. The air locker is a nice setup becaue you can lock and unlock it at will. Lock it up to get moving, then unlock it so you don't spin out.

 

Exactly, this is why when the limited slip in my Cummins wears out I'm going with an ARB and 35 spline axles. As far as checking you axles probably the easiest way would be unbolt the shaft and remove it. If you pull the cover you loose all the gear oil and you can't really get a good look at the end of the shaft on most axles.