Thanks for the reply. Then only thing I have left of my tranny failure due to shaft basically is the yoke on the rear end. Of course there was no major failure of the shaft just extreme vibration that removed the rear tranny seal. I will say on the topic of vibration causing fatigue is that after I left the dyno I noticed vibration at around 90 mph with 3.73 gears and I never found vibration up to 120 before that. Might have been a damaged rear bushing on the dyno but I dunno.

Kbracing- your driveshaft lengths in detail would be good cause according to Mark Williams' shaft critical rpm chart, 2" in length can make all the difference in the world in failure speed. I can't see a mid-sized car having more than 55" in driveshaft length? Also, do you know what brand shafts they were running?

 

PM'ed ya.

after some reading it seems the standard is 50" for nascar. Hmmm.

 

I'm kinda leaning torwards sending mine to Denny's and having it re-tubed since I have good joints and yoke. They may have got the phasing of the ends off slightly when I had it shortened.

 

Mark Williams' critical speed chart. 2" equals approx 500rpm

 

Honestly, I don't remember the exact length Mark, I know our wheel base was 112" on the Craftsman trucks, but our trannys where shorter the yours.

 

True. Didn't think about the trucks. They might have been thin walled chrome moly or something like that.