driveshaft length. help!!!

[NINERS1]

does anyone know how to figure out how much to shorten the driveshaft for a truck lowered 7" in the rear? is there a formula to follow? it is a longbed 2 piece shaft.

[cdowns]

take ruler and measure twice is the correct formula to get it right the first time

[mrhino]

just had mine shortend a week or so ago. There is no Formula. Ask whoever you decide to shorten your shaft, how they measure the length (each shop has their own way) My shop had me measure from u-joint to u-joint with a slip yoke in the trans.

[69 longhorn]

Originally Posted by cdowns

take ruler and measure twice is the correct formula to get it right the first time

C downs, you are one ornery som bich....but I like it The last 2x4 I cut....it cut it 3 damn times, & it was still too damn short To NINERS1, there is no formula for you app talk with your local driveline shop.Understand that every truck is different. I can tell you what I know, but I need a little more input on the shaft you are running(solid in the middle, or slip yolk in the middle)? carzyAl

[NINERS1]

Originally Posted by 69 longhorn

C downs, you are one ornery som bich....but I like it The last 2x4 I cut....it cut it 3 damn times, & it was still too damn short To NINERS1, there is no formula for you app talk with your local driveline shop.Understand that every truck is different. I can tell you what I know, but I need a little more input on the shaft you are running(solid in the middle, or slip yolk in the middle)? carzyAl

I think it's solid in the middle, thought i read there is a rule of thumb [so many " drop = x " shorter, I dont have a driveline shop here but there is a machine shop that can shorten it, but the first ? they will ask is how much!!!

[raycow]

If you are doing any kind of mod that affects the driveshaft length, the rule is "always do the driveshaft last". In other words, get everything bolted up where it is suposed to be, and the ride height where you will be running it. Then measure for the driveshaft length you need, center to center on the U-joints with a yoke in the transmission. Don't fight the tide on this - it is the only surefire method that is known to always work.

Ray

[stich626]

Originally Posted by raycow

If you are doing any kind of mod that affects the driveshaft length, the rule is "always do the driveshaft last". In other words, get everything bolted up where it is suposed to be, and the ride height where you will be running it. Then measure for the driveshaft length you need, center to center on the U-joints with a yoke in the transmission. Don't fight the tide on this - it is the only surefire method that is known to always work.

Ray

sme as above but with yoke not fully in tranny, put it all the way in and then back it out an inch. then center to center of u joint..
when you go to the place making it, tell them how you did it. better yet ask them how they want you to do it..

[prostreetC-10]

What ever you do don't make a very easy mistake and measure with the weight off the rear end if it's jacked in the air. She will wind up way long. Must be on the ground and bounce on the truck to make sure the suspension is settled. Also, make sure to have the proper yolk space when measuring to account for suspension travel.

[NINERS1]

Thanks for the help guys!!! I will do that, after i drop it 2 more inches [for a total of 7] i hope i can get the driveline in to measure!