i did the new post on this so people would see it more.i have had two go on me.yes two.the first on the fixed it the next time they had to put a hole new one on it.the last on was in dec. 00.i have a 97 .4.6 with a powerdyne,and all that good stuff.it is a 8 foot bed ext. 4x4.so it is big.the truck moves out.in april i am going to the track with it to see what it can do.when i was getting the new one put in i asked if the 9 and 3/4 would work,they said not with me having a 8.8 in the front.i don't know if this is true.if anyone knows let me know.i would say if you have more then 325 hp at the fly you my want to take it easy on it.my friend has a 95 svt mustang with a 8.8 and a GT40 with 425 at the fly,work fine.

 

I always thought that Fords 8.8" rear end was one of the best. Many people have that rear end in their truck and have never had a problem. Sorry to hear about your's. Do the gears just blow out. When they take it apart are the gears all ground up? Or are you twisting the axle shafts? I am curious.

 

I'm pretty sure that the only R&P used in the front is 8.8". Check under a 5.4-powered 4x4 sometime. Heck, my SD has two different-sized R&Ps between the front & rear.

You sure the installers are qualified to work on your truck?

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1997 4x4 Expedition- 4.6L, true dual exhaust w/Ravin DI/DO, K&N air filter, SuperChip, airbox mods, Edelbrock shocks, 285/75R16 BFG ATs, 2000 F150 "XLT" wheels, 4.10 gears, Auburn LS, Clarion In-dash CD player, Smitty Bilt push bars and nerf bars.

2000 4x4 F250 SD XLT SuperCab SWB- 6.8L, Offroad Pkg, Camper Pkg, 4.30LS, Tape & CD player, Remote Keyless Entry, Sliding back glass, tinted windows, 265/75R16 OWL tires, Smittybilt nerf bars & Line-X bedliner.

NoMo's site

 

My truck has an 8.8" in the front. At least I'm assuming that's what the big "8.8" cast on the housing means.

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2000 F150 XLT 4X4 Off Road 5.4L Reg. Cab 3.55

Performance Enhancemets:
K&N
WMS Velocity Tube
Gibson Sweptside

Audio Enhancements:
All of the above, plus
Sony C7000X HU
Cerwin-Vega SS2502 components(Front)
Blaupunkt PCxp573s(Rear)

Radio-delay mod

Other Enhancements:
Extang Black Max Tonneau Cover

 

Kevin,

Your Dealer is full of crap. The front of all the 97+ 4x4s regardless of engine is an 8.8 inch with reverse cut gears. The 9.75 should bolt right up to the spring perch. I would be worried about the drive shaft. It may be too long if the dementions of the 9.75 make it longer than the 8.8. That would put the differential compangion flange closer to the motor and require a shorter drive shaft.

Regards

Jean Marc Chartier

 

Yea, the 5.4L 4x4's have a 8.8 in front and 9.75 in back. As long as the gear is the same it doesn't matter.If you have to get a new D/S, you can always get the benefits of an aluminum one if you can find one.

I think the weight of the truck is the problem. The Mustang can only exert so much down force on a launch. The weight dist. of a Mustang isn't much better than a truck. The truck will put more stress into the axle before the tires break loose and become the limiting factor. When I changed the gears in my Mustang I installed a T/A type cover that susposedly will help with the main caps.
Mine Mustang doen't have anywhere near 425 HP, it's still mostly stock, but it does take a beating every time it's driven w/ no problems.
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2000 F150 XLT 4x4 Short Bed. Amazon Green, 5.4L, SuperCab, ORP, Tow Package, Sliding Rear Window, Electronic Shift, Keyless Entry, LT265-70-17 Tires, Clarion Pro Audio, Herculiner Bedliner, Air Silencer Removed.

1994 SVT Mustang Cobra. #1032 of 6009. Black coupe with black leather int., 3.73 rear, Bassani Exhaust, Aluminum D/S, Bridgestone RE-71 255-45-ZR17

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[This message has been edited by 2000 F150 4x4 (edited 03-15-2001).]

 

Yeah, I'd wonder about a couple of things. First, I'd wonder about the installers. Did they really do a good job in the first place? Second, I'd wonder if the gears were broken in properly. The gear contact surfaces are quite soft and they work harden as you drive. If you hammer it right away, you'll wear off the contact points and wreck the gear. It will eventually fail.