hello all

i just picked up a 1994 f150 4x4 with a 4.9 and 5spd. the rear end is very noisy. i would like to know what years would fit my truck? and is the 2wd the same? the tag is missing off the rear end so i don't know the gear? i was told its got 308s or 355s? i can pick up a rear end off a friend but its not out of a 1994. i think its 1989?

thanks for any help.

 

89 is to early you need to get one that has a tone ring for the speedo. you probably have3.55 with 4X4 but you will need to jack up a wheel and check to see what you have by turning the wheel and counting the drive shaft reves.

 

my 88 has that tone ring and the abs but ive yet to see any abs function while sliding on ice

 

You more than likely have an 8.8" rear-end.

It is a lot cheaper to fix the noise than to replace the rear end with another one that may be bad soon.

If it is the wheel bearing just replace the bearings, if the noise is from the center and you have oil in it then just tighten the nut to specifications and see if the noise does not go away. Use an inch lb torque wrench and set the nut to 8-14 Lb-In. You will need a 3/4 drive socket with about a 4 ft pipe to turn the nut and just turn it a little at a time (about an 1/8 turn) and then check it.

 

Yes, I would try to fix the one you have.

To answer your question on the swap, any 8.8" axle from an F-150 from 1987 to 1996 will have the tone ring you need. They will all be a direct swap in. The front also has a tag - did you check it? The rear should be close.

Front: Rear:
3.07 3.08
3.54 3.55
4.09 4.10

 

thanks for the help. i will check the fluid level. and the front tag. the noise is comming from the center of the rear end. it humms and grinds when i let off the gas?

 

Look on the Certification (VIN) Label, (located on the door or B pillar)...where it says AXLE. That code tells what type the rear axle is, the ratio, whether it's a Limited Slip or not and the rear axle capacity. You can use the FTE axle decoder to decode it.

 

That means you do not have enough perload on the pinion bearings and the nut has came loose or you just need to tighten it some like I said above. You may have the same problem with a used rear end that you put in.

Tightening the nut, I made my holder out of 1/4" plate 3 FT long with a torch and drilled for the bolts:


Checking the preload, take the Brake Drums off first:

 

What kind of noise is it? Is it a grinding clunking noise? Or a grinding whirling noise? (trying to find out if it's coming from the center of the axle or the outside ends) If you take the inspection plate off, you can always count the number of teeth on the ring and pinion. As example: 39 (ring) 11 (pinion) 39 divided by 11 = 3.55. I had to replace my center section for about $400. The rear will end up costing you easly twice that. Plus you have to bleed your brakes and then some.

 

Subford, why do you need a 3/4" drive socket and a 4 foot bar to tighten only to 8-14 Ft pounds ??

And in your preload test, is that to test the amount of inch torque before the unloaded axel will spin. And what is that spec ??

 

It takes about 250 FT pounds to turn the NUT.
It is 8-14 Inch pounds not FT pounds.
And yes the 8-14 Inch pounds is the required torque to turn (spin) the unloaded axle with used bearings. Never back up a nut to set the torque.

And use a new NUT, crimp the nut or put lock-tite on it.

 

OK, thanks subford

I'm so weak these days, I might need 6"

 

The 250 ft pound nut, is just wainting for a pun joke........ Don't bust a nut!

 

WOW, I was just turning my axels back and forth to make sure the oil seals are seated smoothly before filling the rear end and I noticed that the pinion flange where the driveshaft attaches moves in and out looks like at least 1/16th of an inch. It wasn't leaking.

Is this normal ??

Does tightening the pinion nut remedy this ??

 

No

Yes yes it can.