2008 4x4 4.6

Looking to put a 9.75 with 3.55 gears in my 08 f150 4x4 anyone know what compatible can I use pretty well any old truck with that axle if the gears match up and replace drums with my old discs just get an adapter kit? Any help would be appreciated thanks

2008 4x4 4.6

I have an 8.8 in there now and it's burnt up so I wanna get the 9.75 with the same gears if I use the drive Shaft from the truck I get an axle from would any old truck work or does it have to be an 07 08 like some ppl have said.

Marc D

I wouldn't stray from any axle other than the same model and generation (11 generation 2004 to 2008) that you currently own. There are even differences within these years such as "limited slip" rearends and "non limited" slip styles.The style and length of the diff. can also make your driveshaft not fit due to length. The range of gears is also very broad, so finding what you want could be difficult although 3.55's are common. A new set of gears and bearings is about $600 + another $200 in parts and gear oil to rebuild what you have BUT the setup is difficult if you've never done it before. I'd get some prices for a rebuild w/ the gears you want

2008 4x4 4.6

I would but the problem I have now is that the opening on the front for the pinion gear is oblong so I need to replace the housing anyway and I hear there bad for this so since I wanna keep the truck for awhile to come if I swap it out now might save time down the road. Even if I had to put a new locker in it at least than I'm bullet proof at the back or that's the plan

Marc D

OK. So if you're going to look for a "swap out" complete rear end you can expand your options by looking at Expeditions and possibly older full size Broncos for donor parts. Even if you have to deal with the driveshaft they can be modified by lengthening or shortening and even replacing the rear yoke at a driveline shop. Besides, almost always, an oblong pinion gear housing is due to an unbalanced drive shaft.

2008 4x4 4.6

Thanks good to know I'll have the Shaft checked for sure they'll have to shorten it so. What's the noise about needing one from a 07 08 I've been hearing form people due to the differential? That's my big concern.

2008 4x4 4.6

I'm assuming it's the ls differential there talking about but I dint know why this would matter unless it has to match something in the front differential but I don't think that makes sense

Marc D

You have to match gear ratios in the front and rear differentials or you'll tear apart your transfer case. The gears in the T-case would be trying to turn at a different speed when it's in 4x4

2008 4x4 4.6

Perfect thank you sir