The Stovebolt Site Forums The Parking Lot Big Bolts New 2 speed axles coming..

Hello all. Just an update on my 1966 C60 and the gear ratio problem. I have located two 1965 rear axles with electronic 2 speeds. These will be delivered at the end of this month or the first week of next. They were pulled from a couple of '65 C60's.

Anybody have any advice for the axle swap? Seems to me it should be straight forward, but then again there are always suprises....LOL..

IC,

Why are you swapping axles?

Mike B

The stock axle is very high geared. The engine is screaming at 45 MPH. I have been weighing options and I decided to swap out for a 2 speed. You may remember us talking about this a few months ago in another post.

you do realize that 2 speed rear gearing is "high and higher"? usually the 2nd speed is a 'granny gear' to help with starting with heavy loads, not a better ratio for high speed use

Bill

Hello Bill. Well it depends upon the stock gear ratio to begin with. My gear ratio is around 7.20 or something like that. I believe the axles I have coming are in the high 5's. I just want to go 55 MPH if possible, LOL......

high 5's would be unlikely, if the single speed is 7.20, the 2 speed would most likely be 6.5 and 8.7, so you might get to 55mph, but it wouldn't lower the RPM ..... for all that work

Bill

So what am I missing Bill? How are these other people getting 60+ MPH out of their 2 tons? Should I install a brownie? Perhaps swap in after market gears in the rear axle? Thanks!

I never got that kinda speed out of my 1.5T, so yes I'd say a different ratio rear or an different trans with an overdrive ratio, not sure what was available in the 60's .... depends on the engine too, if you've got a 283/327 they'll take the revs

Bill

My engine is the 292 six. It runs great and I would like to keep it. Well, when the axles show up I will check out what gear ratio they have. I may need to pull them apart and swap in some new gears.....

If your rear is indeed a 7.20 it is a 45 mile an hour truck. It could have been a fire truck or a government truck. A 2 speed could have been a 6.40/8.72 or a 5.83/7.95. With either ratio, you can go 60 or more. What size tires do you have? However, if you aren't accustomed to those things, they re going to be noisy with a steel fan and no fan clutch and very little noise. But the engine is actually happier wound up than it is lugging.

You're right crenwelge My truck was a service vehicle for the city of Carlton Oregon. It may have had a dump bed at one time but I'm not sure of that yet. At 45 mph the engine is screaming! It likes 40 much better, LOL.....My tires are 9R-22.5. They stand approx. 38" overall. I know of a company that sells 5.83 gears that I could swap in if needed. It all depends on the gear ratio of the axles coming......Thanks!

I agree with crenwelge. i'd LIKE to squeeze a few more M.P.H.,out of my '55 T.F. 6500. It's equipped with the 261,and it does run "happily",at 55 M.P.H. rear tires are 9:00 X 20;00's,B.T.W. My major concern is the PRICE,and LABOR involved,in not only the rear-end/aux. trans. swap,but then the brake up-grade,to make "Her" stop safely,at a higher speed.I'm thinking,that IF I do go that route,I'll probably find and old Chev/G.M.C. bus,('67-'72 ),with either a GOOD 350,or 2nd choice would be a 366. It would have to be equipped with a Clark 5-speed O.D./electric 2-speed rear. I KNOW these will run between 62-70 M.P.H.,un-governed,and loaded "to-the gills". Used to drive one in our band from state-to-state,back in the '80's.

I have a 2-speed in my fire engine with a direct drive trans. It's an Eaton rear geared at 6.14/8.36 and I run between 60 and 65 mph all day long with 11.00 x 22.5 tires. I think the engine is turning between 3500-3700 rpm.

Mike B

Thanks Mike B. That settles it then! When the 2 speed axles are delivered, one of them is going under my truck......55+ MPH here I come, LOL