Now I don't normally drive like a jackass on public roads, but today I was investigating my massive power loss in my 1999 F150 4.2 auto, and decided to do a brakestand.

Now when my truck finally decided it was going to spin a tire, It spun both. That doesn't seem right. Now it's doing it consistantly.

Got my snow tires all chewed up now

Anways I believe these came with an 8.8 right? the door sticker tells me I've got a 3.55 open diff. I have no reason to believe the rear end has been changed, plus it would only ever spin one tire when I bought it.

The rear end is terribly noisy (louder than my snow tires on the august asphalt), and just to be 100% it's not tires, when up on blocks in gear the noise if obviously coming from the diff.

Do you think this is something that is going to grenade on me in the near future? If so did any of these trucks come with a 4.11 gear. I figure swapping the axle would be easier(cheaper) than paying somebody to rebuild it's guts.

Anyways thanks for taking the time to read. I'm not really sure if I've asked a clear question or not so feel free to answer, comment on, correct, or just blatantly insult me or any part of this post.

 

Your spider gears could be seizing up, especially under high load. Make your differential fluid level is topped up.

Now an open rear end can occasionally get both tires spinning on pavement, but if its doing it consistently then I think your spider gears might be in trouble.

 

Yeah that's kinda my fear, last year I had new axle seals put in and new oil in the rear. It was full before I was hoping that was going to help with the noise.

My old '82 Chevette did spin both tires once(you can call me a liar if you want), and my truck always did on gravel but never has before on pavement, and doing it every time kinda scares me...

If the spider gears seize will it just randomly explode and lock my rear tires at 75mph? or could it just turn into a spool LMAO...

 

Seized spider gears would just make a spool. Would squeal the tires horribly around corners. Would probably eventually blow though.

 

good, just as long as it's not going to randomly throw me into a four wheel skid someday I don't care enough about the truck to replace things unless they're a safety issue.

 

Pull the cover and inspect. If it sheared the retaining pin, then the cross pin can come out and hit the pinion or hit the housing and give you a full stop- I have seen them fail both ways. My Courier's cross pin hit the pinion and broke the saddle caps holding the carrier in place, while my F100 hit the housing and broke both front universals in the front axle.

 

Ford_Six

Thats just exactly what I didn't want to hear, I'll hafta find somebody to take a peak inside for me, I don't touch rear ends. Just something I'd rather stay away from.

 

Pulling the diff cover is as simple as removing several oil drain plugs. It won't bite you. You could have broken a piece off of a spider gear or ring gear and it's stuck in the spider gears. If you're feelin' really slick you could truck spinning the tire while driving in a circle so the weight of the vehicles on one side which would for sure make an open diff one wheel wonder.

 

yeah, I'm not worried about that, I'd just rather have somebody look at it who could inspect the gears if I find nothing obviously wrong.

Unless something is just totally smashed beyond all recognition I wouldn't have any idea. The mechanic that had it apart last said, "yup, they look like gears to me"

A guy last summer offered to open it up and fix whatever was wrong that was making the whole thing "clunky" but I wouldn't let him touch it because he was on vacation. Apparently ignoring it wasn't the proper solution. lol

I don't have enough power to do a donut, I would if I could... seriously I even rolled the truck backwards down a steep hill and it would just barely scuff the tires. maybe the whole thing will just explode all at once 5:30 in the morning someday on my way to work when there's nobody else on the road