1995 F150 8.8 diff rebuild
 

Hi! I am rebuilding the differential in my 95 F150 (302; RWD) and I had a question I was hoping someone here could answer.

I am using a new Yukon ring gear and pinion gear in this rebuild along with new bearings, etc. (of course). What I am wondering is if the original shims used on the pinion (or even new shims of the same thickness as the originals) will work with the new pinion or if the shim thickness will be totally different from the original. And if that's the case (and for my understanding), why is it different?

Thanks in advance for reading.:thumbsup:

might be the same might be different. Start with the stock shim and check it.

Each housing and each gear are not exactly the same. You need to put in the exact right combination of shims to set your pinion depth (so that the ring and pinion will mesh together at the center of the teeth.
Then you need to adjust your carrier side to side so that the gears aren't too tight or too loose.
Not setting them right can give you problems - from a whine to premature wear to a broken gear.
Set them exactly right and they should be good for hundreds of thousands of miles.

A few tips. take your old pinion bearing off of the old pinion and then bore the inside of it out using a sanding flap wheel, or bore hone etc. keep boring it out until you can slide in on the new pinion by hand. Its the OLD bearing so its JUNK. This is just for checking.

This way you dont have to press the bearing on and off each time you change shims.. speeds up the process when you can take it off by hand. Once you get a good pattern then press on the new bearing and check it one more time.

And as a side note. every 8.8 I have rebuilt or changed gears on (which really is only a handful of times) If I use Ford Gears then every time the stock shim has worked. And for that reason I will only buy ford gears. (maybe I have just been lucky)

Thank you. I've had to put this job on hold due to weather but now I'm back at it. I have the new bearing on the pinion and started off with the factory shim. When setting the preload, I tightened the pinion nut as much as I could without a torque wrench then checked the preload. The specs I have call for 14-19 inch pounds and I was sitting at 15. I read though that the nut needs to be torqued to around 200 ft. pounds so I pulled out my wrench and set it as high as it would go (click type...180ft pounds) and torqued it down. The preload now reads 40 inch pounds. Should I have not torqued it and kept it where it was at the first preload reading?

After doing more research, I found that the minimum torque was 160 ft pounds so I'm going to pull the pinion out and try again. I have a new crush sleeve so there's still another go I can take.

Now it's sitting at 15 inch pounds. I don't know what the pinion nut torque is...I just tightened a little, measure the preload, repeat. There's no play in it

You should be good with the 15 inch pounds. The actual torque of the pinion nut is just what it takes to crush the crush sleeve, it's just a moot point as far as actually setting the pinion. Again you should be good with the 15 inch pounds.

That's the way I understand it anyway, I have never actually had a differential tore down that far to use this method.

Good to have the affirmation on that. I re-examined it all again and found a small amount of play so I torqued it slowly and checked as I went. I was able to get 170 foot pounds on it and still stay within the preload parameters. Things were going well until I dropped my dial indicator twice and regardless of how many videos I watch, I can't seem to fix the sob so I have to wait a couple of days till my new one comes in. ug.

Meanwhile, I slipped the diff into the housing with the carrier shims. It is a very tight fit and required using a hammer to lightly tap one of the shims in all the way. The pinion turns fine one way but when I turn the opposite direction (making the ring gear go clockwise), it starts to drag some. I can't see anything causing the drag though so I'm not sure what I did wrong...new ring gear, new pinion gear, new bearings. Maybe my pinion depth is off? I used the stock shim, 0.026. I can use a rachet and turn the pinion past the dragging point and it goes back to turning as it should but then it hits a dragging point again. I'm hoping to come up with an idea in the next couple of days so that when the dial indicator comes in, I'll be ready to roll.