rear end ratio

This fall will be my third, (yes count em) third attempt to get down thar to the Ozarks to ride with thet wild Thad Brown Hitchcock gang. I'll be stopping in Smithville to pick up ole Jesse james along the way. So far my best attempt was 89 miles into a 405 mile trip only to break down an return home.

An since the newest Ferd (2011 F-250) couldn't git the job done, well I thought maybe I'd try the oldest one. I don't have ole Ted's 1976 Ferd here yet with thet gas guzzlin 390 here yet, so we're gonna go with a 1991 F-150 with a 300 six banger and 4 speed automatic. It has to pull a 14 foot V nose enclosed trailer with the harley and gear inside, along with the nurse an her stuff. .

it's got 31-10.50 tires on it which don't seem to be much different than the stock 235/75 tires. But I gotta rebuild the rear end. The spider gears are worn out fer whatever reason. An I'm getting this vibration from somewhere. I already tried new U joints and balancing the drive shaft. Do I stay with the 3.55 gears or do something different? Yeah, it's a 4x4.


Edited by Les Royer - 19 Apr 2018 at 5:10am

3.55 seems kind of hi for an OD trucko. Changing to a 3.73 would make it pull better but you’d have to change the front as well. Mine has 3.08 and that’s way too high. Mine isn’t OD.

Well Les, hauling the Harley shouldn't even make it break a sweat. But,....if your nurse packs for a trip the way my nurse packs for a trip, then you had ought to just abort the mission now, until you can put something like a 379 Pete in front of that trailer. Suppose you have a "shoe closet" in that trailer somewhere....? Darrel

I wouldn't regear for a trip. I have regeared trucks that we're going to run oversized tires but 31" is a stock sized tire.
I've got 3.42 in my suburban 245 -75r16 s are 31" diameter. I don't pull my 7500 lb camper in overdrive just leave it in drive and it runs about 2500 rpm at 65 mph. That puts me right in the torque curve and it pulls real nice. With a lighter trailer I use overdrive but it's only running around 1700 rpm at 65 my trailer have trailer (ST) tires they are rated for 65mph just like all trailer rated tires. So I try to keep the speed down.

You know, if you'd a come an got that Ferd, it'd out pull anything you've got and keep on going down the road.....till you get by another gas station.
Are there any auto/truck junk yards around any more??  Change out the whole rear end.

Remember mine is carbureted. The carb is junk. I plan to put on a offenhauser manifold and a 2v or 4v carb.