drive shaft help

[rigon4]

Ok i think the drive shaft is to long in my 85 short step. It has a 502 with a th400 but its had three trans in it in under 10k it keeps wipping out the tail shaft bushing. I just bought it and i only want to put one trans in it. So does anyone know how long the shaft should be??

[1984 swb chevy]

I dont know how long it should be but I do know that your yoke should be out of the seal about an inch. If it is to long the yoke will be against the seal. if it is to short it will leak fluid under hard acceleration. I hope this helps

[Rosscup]

i have a 77 short box 4x4 with a TH350 and a NP208 and its drive line is 43.25 inches long but thats a 4x4 so maybe that will give you a ball park

[rigon4]

with the truck on the lift i had a 1/4 inch to slide the yoke in to get to drop out the rear u joint so thats why i think its to long

[78 Chevyrado]

I'm not sure how much, but from what you say it is too short. 1/4 inch is not enough. I'd think it would be like 1-1.5 inches or so, correct me if i'm wrong guys.

[Damien]

QUOTE=78 Chevyrado;3173015]I'm not sure how much, but from what you say it is too short. 1/4 inch is not enough. I'd think it would be like 1-1.5 inches or so, correct me if i'm wrong guys.[/QUOTE]

The drive shaft is too long. I'm sure you just typed it wrong.

I would crawl under the truck and measure the way your shop wants. That is the only way you can be 100% sure you have the right lenth driveshaft.

[rigon4]

did gm make a short box with a big block and a th400 with a one piece drive shaft if so what year?

[grinch4om]

seat the yoke all the way in, pull out 1-1.5 inches, then you can look at how close the rear joint is to the saddles on the rear end...support the truck with jack stands on the suspension when you do this

[rigon4]

the local drive shaft shop wants a measurement from seal to center of u joint with it on the ground. I dropped the trans pan and its junk there is chunks of aluminum.

[Cherub]

+1 on getting the shop a correct measurment.