cross-member question

[i heart square bodys]

hey guys , i have 2 frames , one had a hanger bearing and the other did not. just wondering about the frame that did not have the hanger bearing. did it ever have a cross-member between the 2 rear cab mounts like the hanger bearing counterpart does ? or was this cross-member un-needed due to the fact that its a single drive-shaft? thanks guys !

[i heart square bodys]

Cummon guys somebodys gotta know...

[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?

[i heart square bodys]

Both frames are half tons , one had a 700r4 amd 2 pc driveshaft the other had a th350 and a single driveshaft . Just want to know if the single driveshaft 1500 ever had a crossmember or if it just had the cab mount brackets.

[KrazyRay]

The 1/2 ton single drivelines just had the cab brackets. There should be a small crossmember between the 2 for the fuel lines to run along.

[i heart square bodys]

Thats all i needed ! Thanks !

[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.