I'm glad to see you've figured out the problem.

The difference in sizes is difficult to see from outside unless your a little experienced. But from the inside....your crown gear, (the big circle one) is a 9" f-250, most regular f-150's like mine have the 8.8" gear. The bigger the gear the more power or maybe strength it can handle.

The 3.55LS is your gearing. The higher the gear ratio the more torquey, and slower it turns. I hope i answered your question.

I actually just had mine apart this weekend, i had a noise in there when i hit a pothole sorta sideways, it would rattle. But i never found anything that could be fixed. And the dealer said it was normal......don't you get tired of that.

Paul

 

Your front diff is a dana 60 ( i think) , if it is indead from a superduty.If this is true, I have good news for ya, a chrome cover is available for the front diff .I just picked one up today and I will have the shop put the front one on because they will be working on the diff anyway

 

Just returned from the Ford Dealer. My seal was replaced, in about an hour. No unusual reason found, for the leak.The Mechanic also added 4 oz. of fluid, to top it off.

The Mech also pulled a sample from bottom of the Diff. He says it is good, and no unusual wear. He says it was the Friction Modifier.

In the past, on other Ford's I've owned, I hadn't seen that much material on the plug. Anyway, it is still under warranty if anything goes bad.

Also, according to the Mechanic, I do have an F250 rearend in my truck.

Thanks for all the input. I am aware of the Gear ratio and all, just wasn't sure about the difference in sizes of the rearends.

Have a good week all...

R1968

 

Hi Ranchero1968, small world. I was stationed at Biloxi in 68'-69' and like your wife I was from Terre Haute. I was in TX 71'-72, and now live in WA. The worst weather I found was in Terre Haute. Your wife will get use to it and not even want to go back to Ind. to visit. I have a 01' Scab and am getting ready to do a gear swap, putting in 3:73 gears, been reading all I can about the swap and am a little apprehensive, but plan to save about $400. I can buy more goodies with that.
J.J.

 

I had a low pulsing hum start in my 98 F150 at about 80K miles. I drove with it for a few months then took it to the dealer. It turns out it had eaten the bearings on the driver side and the shaving had worked through the seal and into the differential. Ate it up completely. It never made a noise when the bearing let, only once completely wrecked did the humming appear. Mecanic said it was a bad design in the differential in the 98's with only one set of weak seals between the rear hub and the differential. Even with 88K on the truck, Ford covered the cost over $500