cross-member question

[Desert1957]

Originally Posted by tucsonjwt

Just guessing, but I think the two piece drive shaft was only for the C20s and C30s, so there would be no need for the carrier bearing mount on the C10 frames. The 1/2 ton and 3/4 ton frames are different, as I am sure you already know. Do you have one 1/2 ton and one 3/4 ton frame?

My 87 R10 has a 2 piece drive-shaft with a center bearing...

[Metalshapes]

The reason for the difference in driveshaft style is due to rear gear ratio, the lower gears (numerically higher) got two piece shafts with a center carrier bearing, the higher gears (numerically lower) got one piece shafts with no carrier bearing. I forget where the split happens, I think it's at 3:42 anything lower got the 2 piece shaft it might be 3:08 though, anyway Keith would know that.

[D13]

Actually it has to do with harmonic frequencies and driveshaft whip. Keith did a little blurb on it a while back. In general either system will work for a DD, at the worst your joints will need replacing a little more often.

My 250 3OTT are all 2 piece, both 1/2 and 3/4 with 2.73 and 3.43 repsectively. My 250 TH350 3.08 is 1 piece, and my 6.2 700R4 3.08 is 2 piece.