I'm running the 3.08 8.8 Non-LS rear right now. Thinking of upgrading to 3.55 or even 3.73.

I want to get a complete axle so I can swap drums for disc. Is there some major difference between the 8.8 and the 9.75? Either for the 3.55 or the 3.73?

Has anyone upgraded from the 8.8 3.08 diff to a completely new axle to get rear disc? Which ratio did you decide on, why?

Thanks.

 

I also have the 3.08 non-LS 8.8 in my truck. I think im am gonna go w/ 4.10's because I have the 4.6 plus I have 32'' BFG's. I have no need to change the axle because I already have disc's all around. I too am curious as the what people say because I still cant decide on either 4.10's or 3.73's.

 

I'm not really asking about 3.55 vs. 3.73, I want to know the main differences between 8.8 an 9.75. Would I benefit from a 9.75 if I tow a boat during the summers. I have a 2WD 4.6 supercab '98 150.

Any "real" benefit to having the 9.75? If I am going to buy a complete rear assembly, then I should go with the 9.75 if they are going to be the same price? Would it be over kill?

 

No such thing as overkill, if you didn't break it, you ain't tryin hard enough. The 9.75 is just a bit beefier than the 8.8. If you can get one, cool!

Myself, savin up for a 10.5 for one of the broncos.

Adrianspeeder

 

IMO, it would be overkill. The two things that usually kill rear ends are shock loads (think Mustang on slicks dumping the clutch at 6k on the bottle) and heat. Obviously, one of the things that leads to lots of heat in the 3rd member is load; like towing a trailer up a hill. A really long hill. Frequently.

However, being that your truck is a 4.6L, I think that you'll run out of motor long before you run out of rear end (minds out of the gutters, people!!); the 8.8 is really a pretty impressive piece. Look at the new GT500s... they're running that 500+ hp blown 32V 5.4L through the same rear end. Granted, the car doesn't weigh as much as a truck (though it really isn't that far off, at something like 3850 pounds) and isn't towing a trailer, but it IS taking high shock loads and generating LOTS of heat in the twisties (the limited slip clutches of course generate heat when allowing one wheel to turn faster than the other).

I think that if you go with the big nuts rear end, your truck will be slower and put less power to the ground. The reasoning behind that is that the 9.75 will be considerably heavier than the 8.8, and more importantly, will take more power to turn due to the heavier components.

 

I have 5.4L 3V with 30's (2wd) and I dont like 3.73. I want 4.10.

If you are running 4.6L with 32's I would consider going straight to 4.56. 2400 rpm @ 70 mph.