Will a 9.75 inch rear end bolt up right in place of my 8.8 inch rear end on a 99 f150. Im thinking about putting a limited slip in my truck. I have found a few of the larger axles complete and wanted to know if i could just swap the whole rear axle assymbly.

 

I'm not sure on your question,but i noticed you said you found some 9.75 rear ends and I am desparately in need of one with 3.73 gears,can you tell me if you know where one is and what sort of price they are?

thanks

 

MechE, the rear ends will swap right in. Except for the driveshaft, you will need a shorter one, as the 9.75 places the pinion flange about 1 to 2 inches closer to the trans. Either have yours shortened, or get one for your year truck with the 9.75. I did the same swap, but my truck came with drum brakes originally, so I had some brake issues there. But it came out good, I also got the right side shock mount for the lightning, and installed it on my extra cab. Now all wheel hop is gone.

 

MechE,

It is a small world indeed.... I will be swapping my POS 8.8 for a 9.75 so I am picking up the 9.75 in Columbus Ohio Monday. This company bought out an over run of Sterling axles. They had 7.5 to 10.5 inch axles. The one I am getting is model S919D. It has 3.55 gears and a limited slip. $600.00 US. svt is correct the pumpkin is larger on the 9.75 so the flang is closer to the tranny.

rbjb99,

I can check on Monday to see if they have any 3.73s left.

svt,

Did you reuse the same U-bolts? Is the pinion flang the same as the 8.8? I will need a custom drive shaft or I might get the OEM shortened. It is an odd duck, 5speed tranny 4x4 so I don't think Ford has a stock shaft for it.

Regards

Jean Marc Chartier

 

SVT, I am on my fourth rearend in my 2000 f150. I have been considering changing to the 9.75 from the 8.8. Is the 9.75 stronger than the 8.8? It sounds like a stupid question but I have been told that the 8.8 is plenty strong for the truck that it is in and that it is used in many racing applications. My greatest concerns are with the brake system. I have four wheel discs on my truck now. Were discs what was on your replacement axle and do you know if there is any problem with the ABS being compatible?
Rear end #1 - stock from factory
Rear end #2 - replaced by ford under warranty
Rear end #3 - replaced by friend, also changed carrier to eaton limited slip
Rear end #4 - warped eaton carrier, installed new ford powertrax limited slip carrier, and changed gear to 3:73. Front Drive shaft in tool box to avoid wear until I ave another $1K to change front gear.

I now have the gear oil checked every 1500 miles to ensure that it is full and clean, but I have a feeling I will be on #5 before long.

I do not tow anything and I do a little offroading

 

hoback and MechE

I just completed the swap from 8.8 to 9.75. Every thing bolts right up except for the driveshaft. My application, 5speed, is unique and Ford doesn't have a Drive Shaft for a 5 speed w/9.75. I had it shortened 1¼inch. The spider gears and side gears are quite a bit larger on the 9.75. I would guess 2x. The diff case is also larger, re the 9.75 inch ring gear. It is incouraging to see that I am not the only one going through 8.8s. This one is my 4th also.

BTW they have a bunch of 9.75 with 3.73s.

Regards

Jean Marc Chartier

 

Its good to see that someone besides myself has a 5spd in their fullsize 4x4 SC pickup. I had to order mine to get it that way and I tried to get it with a 5.4. But you have to go to a 250 to get a 5spd connected to a 5.4. Thanks for the info, I'll keep an eye out for anything you might learn about that pinion flange and U-bolts. Keep me posted.

 

hoback150,

My 97 ate up an 8.8 rear end in stock trim. The tranny and rear end would not hold up to the power of a stock 5.4. With my mods I am putting out close to 285 HP and 350 ft/lbs. Could you imagine what a modded 5.4 would do to it. I also, had to order both my 97 and 00. The dealers here in Windsor do not make a man's truck.

Regards

JMC