I'm young and dumb with a lead foot with a truck that is boosted and I seem to keep stripping the Spyder gears in the rear end. I have a 3.55 with factory ls. At first I had 33 11.50s and after about 25000 miles with the way I drive the gears finally stripped out and I put it back together with junkyard parts. but recently removed the super charger and I went up to 35 12.50s and the driver side spyder gear is now stripped. I was wondering a good way to beef up the 8.8 so I wont continue to have this problem I'm thinking locker or just lower gears any help ? Ps I would like to keep the factory 8.8

 

Swap it out with a 9.75 rear from a salvage yard.

 

The good news is if you do it carefully you wont even have to take the braking system apart. The backing plates and hard lines all transfer to the 9.75 which means it could be swapped out in a few hours. I would throw in some new seals while its out of the truck.
Good luck!!

 

I want to keep the 8.8 if I can

 

Then go with a detroit trutrac and ditch the spiders all together. I've personally destroyed 3 8.8 rear ends. The 9.75 is
dam near bullet proof. The 8.8 works great in light cars like the mustang, but in the heavier trucks with more torque
Not the best idea ford had.

 

8.8s usually have no problems and have been proven hp to well in the 1000's. I'm not sure how you manage to keep tearing up the gears but are you rebuilding the rear with new bearings and new clutches in the clutch pack? I'm running a little over 500hp in my mustang and the rear I feel is the most solid of the drivetrain. If I were you, I'd rebuild the rear with all new bearings and carbon fiber clutches in the trac loc and be done with it. Or @01 gt f150's idea.... 9.75's are the bees knees!

 

I'm going to go with all new bearings and seals and replace the gears with a powertrax trackloc but no last time I just replaced the gears themselves not the clutch pads or anything and I new that's why the gears went out so fast this time but before I had it supercharged and after about 30k it bit the dust from burnouts with 33s and 400fp of torque and I didn't blame it for going out after that beating

 

May need to regear for the bigger tires. Burn outs and hard driving with that ratio and tire size is hard on any rearend regardless of power. I'm a mustang guy I'm only over here for my brothers truck 8.8 are strong but I've seen a few destroyed in stock GT's with nothing but drag tires and lower control arms. And that's with about 300hp. In stock form the tires will spin before the power does its damage. A trick we use is going to a higher spline count diff and axles. Not sure what the stock f150s use but there are plenty of upgrade kits around for the 8.8 with higher spline counts and hardened shafts/ gears. Search around I'm sure they have some f150 kits as well. Also going to a 3.73/4.10 or higher may be a good idea. There are tons of calculators online where you can plug in a tire size and get a good ratio for your setup.

 

Yeah I definitely thought about going with a lower gear cause it only has a 355 but I like it for the Gass milage and mine has 31 spline axes but I have ordered a locker to replace the gears what bearings and seals should i replace. (Not removing the ring and pinion due to not having a dial indicator )

 

I would try to do them all if you can dial indicators aren't to expensive from places like harbor freight or the other discount tool stores. If the pinion bearing is bad it can throw things out of alignment and cause you to shear teeth on the gears. You may find it to be a wash though with the bigger tires you have the gearing up effect. So going to something like a 4.10 might balance out to higher mpg while taking some strain off the parts. Check one of the calculators it takes into account cruising rpm. Find something a little lower that doesn't affect your rpm too much.

 

A truck is a lot heaver than a mustang. The bigger rear end is the best option.