The Stovebolt Site Forums The Parking Lot Big Bolts Can gear sets be found for TF

Big bolt rear ends?

Yes plan on spending around $450 for a ring and pinion set if you know the part number http://truckpartsinventory.com/ this is a good place to start.

Will the stock 261,(in good condition),have enough torque,to make a different ring/pinion-gear feasible? Seems to me that you would have to either down-shift the trans.,or rear-end,every time you tried to climb a hill,of any grade. Anybody done a swap like this,in a T.F./261/SM420/2-speed rear? If you're swapping ring and pinion,HOW do you know which set to order? Do you write down the #'s from the existing set,and HOPE the parts guy knows which set(S),will match? I'm "running"9:00X20:00's,on the rear,F.Y.I. Thanks for the help,guys!!

http://wellertruck.com/lit/Weller_Diff_Catalog_2011.pdf

Here you can find the part numbers for gear sets and individual ring and pinion numbers.

As for the stock HP it may be tough for it to run those gears but in mine I have a modern 350 so I don't think I will have any trouble.

Wetwilly, you could figure the torque required to run at what ever speed and road conditions, GVW etc. And calculate the required ratio to accomplish that.
Problem is the best way to figure out that loading at first would be to use a dynamometer. Or compair torque required of a known vehicle and its specs. I guess I'm not being to clear.

Also best to figure estimated truck and trailer? loads, type of hills to climb, required trips, etc. If all short trips, 5 or 10 MPH slower probably not make too much dif. If you're on the 'dry side' and never have or want to drive to the coast, then don't need such low gears. If light loads, flat roads, can probably cruise faster, higher O D ratio.

It might be more expense to install higher R and P, if available, less flexible shift options; less expense, more work to install Brownie, more shift options-it is nice to be able to creep around steep location, large load, backing w/ a trailer that a Brownie allows.

There's something else to think about. These old trucks most likely came with 7.50 x 20 tires. My buddy and I both have big bolts. Our trucks both have 261's ,both had the bigger incorrect tire size when we got the trucks. Living in the mountains we had troubles making it up hills without having to downshift to 2nd gear. He has been able to install the 7.50's and now has no problem keeping up a decent speed going up and down the hills.

Thanks,Ed! I'm in Iowa,and we have plenty of hills in this State,especially along our many river valleys. Where I plan on driving my truck,(when brakes are up for the task),there are plenty of 5-6% grades,but many miles of flat to rolling hills until I get to that area.Plan on making the trip with a minimal amount of weight,just my camping gear,and guitar.Are you suggesting swapping the SM420 for a Brownie 5-speed/O.D. unit,or installing a 3-4-Speed Auxiliary unit? If you're suggesting a B.L. Aux,where would you find the linkage,if purchased from a truck with a different wheel-base?

Plus 1.

A Brownie is an aux. trans, works fine w/ 420, etc. Nice to have the OD on level and downhill, direct, 3rd. direct on hills. I drove across S. Iowa w/ 302, 280V(direct), Brownie, lots of useful gears.

Shift linkages for a Brownie are easily made of EMT or water pipe, don't worry about that, just make sure to get the shifter itself.

Thanks,again,Ed! Much-needed info,not just for myself,but for a BUNCH of us,that want to get the most "bang-for-the-buck",out of our "Big-Bolts"! Much Appreciated!!