rtabish

i bought this 1988 F-150 2WD with a 302/4speed OD a couple months ago, and i am concerned about a problem i am having with it. how sturdy are the rear axles on these 2WD F-150s? this one seems to be a limited slip unit, and the guy i got it from admitted to using the truck "to get firewood".

overloading a half-ton truck is a sure-fire way of trashing an axle that isn't heavy-duty enough for the task...and i fear the wonky action i am experiencing might be signs of eminent failure of the rear end. it is not howling or anything...no clunky noises when engaged, either forward or backward, but it seems to lock up one side or the other [more the passenger side than not] of the rear wheels when i first start out from a cold start.

it might just be related to the rear brakes, and i am going to explore that issue first, but i would like some info on my rear axle if i find nothing wrong with the brake system. replacing the axle is a "worst case scenario" that would probably be more expensive than the truck is worth.

is there anything i need to look for? i did notice there is a tag on the axle, so i can probably ID it specifically, but i am looking for a general consensus on its reliability and sturdiness from someone more experienced with these units.

byoungblood

I'm willing to bet that at one time the gear lube was changed and they didn't put any friction modifier in there. I'd change the lube again, this time with friction modifier, and drive it a bit and see what it does. If not, then you may be in for having the limited slip rebuilt, which isn't a terrible job.

It will also give you the opportunity to inspect the rest of the axle. 8.8" rears are pretty durable, all things considered.

tomb1269

I be willing to bet the leaf springs have been beat to He!! (possibly even a cracked spring) and that they flex much easier. So therefore under torque load from a stand still the passenger leaf is flexing up an allowing the tire to get loose and spin easier.

brulaz

And if the springs are beat up, what about the rear axle bearings?

rtabish

the springs, themselves "seem" fine....i used the truck to haul my riding lawn mower and a few other weighty items, and it sagged but didn't see to drop too much or more on one side than the other. i didn't see any missing or bent springs on either side, and it rides just fine both on the highway and the pot-holed and wash-boarded roads around here.

as for the limited slip conditioner and the lube in the rear, that may be a very good place to start. if it hasn't been replaced since the truck was new, it probably needs it, and if it were replaced with the wrong stuff, it definitely needs it. judging by the mess that is on the undercarriage, and the fact that the P.O. admitted to using the truck for getting firewood, it would not surprise me if he had gone through a lot of mud and water, exposing the axle to possible contamination...and if so, i wonder how long he drove it like that...