Hey everyone,
I am looking for advice / experience with ring & pinion on a 1991 4wd F250 w/460BBF and 5spd manual transmission. It has a 4" lift, 35" tires and stock 3.55 gears. At approximately 70mph I am turning ~ 1900 rpm and I feel like it should be in the 2500 rpm range @ 70mph. Its not terrible now when I'm running empty but when I hook up to my 8k pound travel trailer I rarely hit 5th gear to keep it on the power.

If any of you guys have a similar setup and have done a re-gear what did you end up going with or what did you wish you went with. I was thinking 4.56's would be nice but im concerned that might be too low. 4.10's seem like they wouldn't change it too much and might not be worth it. Thanks in advance!

On a side note I recently made a custom traction bar setup that made a HUGE difference in getting power to the ground and stopping my horrible axle wrap/wheel hop.

 

Well, jumping to a 4.10 will put your 5th gear rpms within a couple hundred revs of where you currently run in fourth. So unless you are struggling to get to speed safely, I'd just run it in fourth when towing and save the $$. If you can't get going or merge safely then maybe do a gear swap.

 

Stock tire size was 31"? If so rpms at 70mph was only about 2100rpm and matching that with 35's would only require 4.10 gears. But 8k is a lot of trailer so maybe consider 4.30 gears for a little better than stock performance.

 

If towing fully loaded trailers every day, I'd consider 4.56. But for average DD'ing, I think 4.56 would be too low. 4.10 would probably get you where you'd be happy.


I have 4.56s with 36" tires, but put them in for the off-road benefit.

 

Also keep in mind how much buck you're going to have to spend for the bang. A decent rule of thumb for regearing is about $1000 / axle (less if you do it by getting a junkyard axle, or of you can do the setup yourself). Are you unhappy enough with your 3.55 gears to justify dropping 2 grand? Running in 4th when towing isn't so bad...

 

Since 4.10s were available factory, they can be swapped cheaper. 10.25 rears dont bring much, should be able to pick one up with 4.10s for $2-400. I dont think asmany f250s came with 4.10s, so used front diffs might be harder to find.

 

Ok sounds great and thanks for all the quick responses. Sounds like I'll keep what i have and save some money. Guess I could spend that money on a MAF conversion instead I'll keep an eye out for a 4.10 stock front D50 3rd and rear axle to swap in for the right price. Thanks again!

 

id swap in 4.88 gears.that will give you 4:42 effective gearing.with the big heavy meats,it should then feel like oem tire size with a set of 4.10's.right where you want to be when towing 8k for a approx 15k combined gross with a gas engine.

as for saving money.that question should of been made prior to the lift and big tires.gears with a lift and big rubber go hand in hand.there shouldn't be one without the other imo.

 

A gear change is always a good time to go Dana 60 in the front...

 

This is sound advice.
As for the gears, I'd go with 4.30 in your situation.

 

At some point my goal is to have 5.13's or 5.38's with a gear vendor in the driveline. Just depends if I stay with 33's or go with 35's.