So there's currently nothing wrong with the two speed T170 rear axle which I upgraded from the original oval housing 15,000lb axle that I couldn't get bearings for, back in the '90s. Said axle upgrade came out of a 1967 Chevy C60 and it also got me the wider 15x5" brakes versus the 15x4" that my bus came with. It was also a totally bolt in upgrade, my Dad and me did it in an afternoon. My only issue with this axle is that it's still the slow old 6.4:1 (or thereabouts) high gear ratio and I'm spinning 3650RPM at 65mph, with the 8.25x20" tires at a hair under 37" in height. That's wound up pretty tight for a big 500cid Cadillac V8, and since I do have said burly V8, the 5:81 ratio ring and pinion would get me down around 3380 RPM. That's a pretty notable difference and would make that big V8 which likes to lug, very happy versus the tiny 327 from 1965 that liked to rev.. and spent all its time on hills in low range of third gear. With the big Cadillac V8, it's rare that I actually need to use the low range. The two speed shifts with authority however, and its level of howl in low range is the same as or less than every other one of these rigs I've ever driven or ridden in. Would be inclined to leave-R-be.
One more benefit of the taller gears is that, along with the brand new 22.5" non-widow-maker wheels and radial tires, I could cruise comfortably in the vicinity of 70mph versus 58mph. Additionally, the modern wheels would allow a tire of about 2" greater diameter and the gear ratio calculator says I'd gain a couple hundred RPM lower at 65mph. That's also not nothin,' getting down to a comfortable 3200RPM.
I've Googled my brains out and I can't find a higher ratio ring and pinion. Maybe if I had the part number for said gear set I'd have better luck? I know that they made taller gear ratios, as I've found a used third member out of a '78 C60 that is the 5.8:1, and it's not unreasonable at $1260. However my current setup is really still good, I would be comfortable with putting in the new gears myself, only replacing bearings if they look to need it. But I don't think they're bad, the axle has no clunk when going from drive to float to coast; I've stood over it while friend drove the bus on the highway, and the tires made more noise than the axle, which has just a slight hum, that I don't think is abnormal for a unit this big spinning that fast.
I guess I must just like to make more work for myself on this rig :-D
Edit to add.. can't seem to find any instances of this P/N in the wild, will have to call Weller in the morning. But wow, 3200RPM at 65mph sure sounds a lot quieter than over 3700.
If it helps others, here is a link to the downloadable Weller Identification Catalog. I found it when looking for possible ratios for my EATON 1350 2-speed:
Ditto on the Brownie, which will turn your 4 speed into a 12 speed, and add overdrive to the top gear, and you'll have two shifters to play with. With the 2 speed rear end, you'll have 24 forward speeds, and six in reverse. That's enough to satisfy the most dedicated gear jammer! That's what I intend to do with the 51 GMC 3 ton I just bought. LOL! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I bought one of those back in the '90s with the intention of doing just that.. it was big, super heavy, I would have had to fabricate and weld a bunch of frame parts for it. Plus all those extra shift knobs!! The bus is converted to an RV so I don't need 24 speeds, I just need to go highway speed without maxing out the motor all the time :-) Sadly I don't still have the Brownie, which would probably be worth some money to the right truck owner.
Looking at the Weller page David posted they only list two 2-speed gear sets, one with 6.50 and one with 7.17 high gears, nothing better that you have now.
Your 8.25x20 tires are kind of small for a 2-ton truck, have you thought about stepping up to a 9.00 or 10.00x20? If you end up with 22.5 rims remember the tire sizes are not equal with the 20's, they are one number size bigger, but are the same diameter.
8.25 x 20 = 9.00 x 22.5 9.00 x 20 = 10.00 x 22.5 10.00 x 20 = 11.00 x 22.5
I searched this very subject extensively sometime back as two of my trucks have corporate T-170's with 6.50's and I wished to find ANYTHING with a better ratio for highway driving. Eventually I called one manufacturer (sorry, been long enuff that I cannot remember which manufacturer) to see what - if anything - could be purchased, or send my unit in for rebuilding with a better ratio. The individual told me the best gear available for the T-170 was a 4.88 but that gear was impossible to find. His recommendation was to get away from the corporate rear as these were extremely limited with gear options, and to consider finding an Eaton rear as gear options were bountiful and I would have no problem finding a more highway friendly ratio.
Being in a rather rural area combined with a well defined case of laziness, I have yet to find an Eaton.
I hope someone with more knowledge on this subject will chime in and correct me if I was given inaccurate information.
KC, I think your information about finding a more modern rear with better gearing will be WAY easier than trying to find gears that haven't been made for 50 years.
The Isuzu NPR or NRR might be a good place to start looking.
Heh, the axle in my bus is already the modern upgrade! It originally came with the banjo shaped housing T150.
A new rear would mean new brakes, a new wheel bolt pattern, probably moving/welding spring shackles.
Since I'm lazy, and this axle was actually made into the late 1980s, I'm going to keep looking. There are 5.54:1 gears available, somewhat. Weller has a used ring and pinion set, it's $600, but that's a lot cheaper than the above mentioned new axle adaption hassle, especially since I just bought all brand new 22.5" wheels for it. @Mike B also yes, I'll be putting taller tires on it too. There's plenty of room in my wheel wells.
