Driveshaft Too short on a C10 I might buy

[jgage]

So I went and looked at an 86 GMC Sierra short bed today that I was hoping to (and might still) buy. It would be my first square body and exactly what I’ve been wanting for so long. In the ad the kid said it needed a ujoint and was otherwise a good runner. Well he was half right. The 350 ran great. The trans seemed to shift really well. He said it was a TH400 but I’m no expert yet. The problem was it’s not a u joint, he said his “buddy” put a new driveshaft in it for him and said that it had a bad u joint. Well the ujoint seem fine driveshaft doesn’t slip in to the back of the transmission very far at all. You can wiggle the driveshaft and see that it’s moving in the back of the transmission. It is dripping fluid just a little as well, I’m assuming because the shaft isn’t far enough in or the vibration has ruined a seal at the rear of the transmission. If you are giving the truck any throttle at all it runs smooth as butter. When you let off throttle it vibrates BAD. I’m actually surprised that with it just barely slipped in to the transmission that it doesn’t sling it out because it vibrates so much. If I get a driveshaft for this thing what are the odds that it’s done damage I. The back of the transmission? That’s my concern, I can buy a driveshaft but if it’s messed anything up inside it my wife is gonna be pissed when I sink more money in it. Any help or pointers would be great. It was so hard to walk away without this truck because I wanted it so bad but dang that driveshaft concerns me. Thank you in advance.

 

[Ricko1966]

I wouldn't be concerned a bit.The tailshaft un bolts so even if the splines are a little buggered pull the tailshaft and file/ grind everything straight enough to slip a hole in. Rebush and reseal the tail shaft. Boom good as new.

 

[jgage]

Well I talked the kid down a bit more and made the drive back over there. Drove it home today. A buddy of mine knows a local guy with about a half dozen c10 driveshafts, I’m gonna test fit a couple and get an idea of the right size and get a new driveshaft. So far though, I’m in LOVE with this truck.

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[jgage]

I wouldn't be concerned a bit.The tailshaft in bolts so even if the splined are a little buggered pull the tailshaft and file/ grind everything straight enough to slip a hole in. Rebush and reseal the tail shaft. Boom good as new.

Thank you for your answer! It’s a big part of why I ended up with my new truck!

 

[Ricko1966]

Thank you for your answer! It’s a big part of why I ended up with my new truck!

Spell check got me a couple of times there.I went and fixed the original post, anyway you got the idea.700r4 & th 350 use the same front yoke th400 uses a different yoke and will more than likely need an odd ball joint to mate the yoke to th350/700r driveshaft. NBD precision has a chart that lists joints by dimension and clip location as long as you find a little longer tube the rest is easy peasy. If all you kind find is 1 that's too long I can teach you how to shorten it the right way. And glad I could help. Nice truck, have fun with it.