gear ratio

[snoplay]

will a 2 1/2 ton third member out of a 1953 M35 inter-change in a 1970 M35 both are top loaders

 

[gringeltaube]

Yes.

 

[snoplay]

THANKS Gringeltaube!!

 

[Barrman]

Umm. The '53 might or might not be a Timken that had CV joints instead of u-joints at the knuckles. If so, then the '53 will have a smaller axle shaft diameter and a different spline count. There are several threads on here and across the web about Rockwell axle differences.

If you are changing the upper two gears on the middle section, it won't matter. Do a little more research or list out what all you need to swap out for us.

 

[rustystud]

Umm. The '53 might or might not be a Timken that had CV joints instead of u-joints at the knuckles. If so, then the '53 will have a smaller axle shaft diameter and a different spline count. There are several threads on here and across the web about Rockwell axle differences.

If you are changing the upper two gears on the middle section, it won't matter. Do a little more research or list out what all you need to swap out for us.

No, that is not correct. All Rockwell differentials used a 1.62" shaft size with 16 splines. Your probably thinking about the M135 2.5ton which used a totally different axle then the M35's used. Also the old style 'U'-joints (Rezepa) are in fact really well built 'U'-joints. If you look up the "ultimate" in front axle shafts you will see they are Rezepa style and cost about $3000.00 each. The military went to the "cheaper" Spicer style for cost reasons. Also you don't need to replace the whole axle if the 'U'-joint breaks with the Spicer style which you must do with the Rezepa style joint. Now there are several "aftermarket" axles for the Rockwell differential which have different sizes and spline counts but the original is still 1.62" diameter with 16 splines.
So for all those running older Rockwells don't worry about your front axles falling off or anything like that. Another thing to mention, the steel in those older differentials is a better quality then the later 1970's or 1980's units. If your a welder you know what I mean. The high quality iron/steel the US produced was used up by the 1960's due to the vast quantities used by WWII . Since then we have been using a second rate ore which still makes a fine product (with additives) but it is not near the quality of the good old stuff.

 

[snoplay]

Thanks gonna pull a rear third member and put in the front diff then rebuild that one for an extra (pinion bearings shot)