1986 drive shaft

[86charcoalsierra]

I recently installed a 454 out of a 1985 Chevy Truck into my 1986 gmc Sierra. Also put in a 400r transmission out of same truck I had a 305 in my truck with the 350 transmission. I used the drive shaft that I had but it is about 2-3 inches to short. So it leaks alot of transmission fluid. Need some help on what drive shaft I can use or if any body know where I can get one around fort Worth tx. My truck is a short bed with stock differential. Thanks for the help.

[Irish_Alley]

the way i see it your th350 should of been about 27 11/16" long the th400 is about 28 3/8" long. so the driveshaft should fit good, the problem you might be having is just a bad seal

[86charcoalsierra]

I already replaced the seal. You can see in the picture that I need about 3 more inches I'll have to measure to be sure. The slip yoke is only about half inch inside transmission. The yoke on back of the transmission had a nut so it was flush with the back of the transmission. When I went to install drive shaft it was to short so I took the nut off and pulled the yoke out until it would reach. It's bearly in there pretty sure if I hit a good bump and catch some air the shaft Will fall off.

[Irish_Alley]

ahh so you had a bolt on yoke and now you have a slip. this changes things a little

[86charcoalsierra]

Yes that's what happened any ideas.

[roundhouse]

Pick up the right shaft at a junk yard
Even if it's too long
Lot cheaper to get it cut down shorter at a drive shaft shop
You have to have a slip joint
Either in the shaft or in the transmission
But you can't have two

Sent from my iPhone using Tapatalk

[Irish_Alley]

yeah thats about all i can think of. put the bolt back in the yoke and measure from yoke to yoke then go to the yard and find a driveshaft with a similar size and Basic stub and slip yoke type driveshaft