73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: budget builder on July 27, 2015, 04:29:29 pm
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im torn between getting one made and trying to get one that will work. I have a 77 gmc c15 short bed stepside. and I dropped in a 454 with th400 and of course had to move the tranny xmember back (holes were already there) and my rear is a standard 10bolt (I think) the tranny has a bolt on yoke that came with it.
the center to center distance ujoint to ujoint for a one pc driveshaft is with my best measurements (59.5") and I cant seem to find a DShaft. what is the best thing to do?
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should be a common drive shaft it doesnt depend on the motor but the trans/transfer case axle and bed style. so you should be able to find one from a th400 from a 73-81 12 bolt. i think 78 was the first year for the 10 but i could be wrong
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calling salvage yards and some don't know what I'm talking about. or telling me nothing they have will work. wagners-durham,nc told me about a place called triangle driveshaft, durham, nc and that they would have to make mine. #ughh!
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they dont have to make it, its very common. drive shaft shops arnt into business of selling used drive shafts would be nice if you had some measurements so some yards can just measure their stock pile. sometimes junkyards will bend them on laziness cause they pick the truck up with a fork lift. someone on here should have your setup and should be able to measure their shaft for you
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Shortening a driveshaft is pretty simple and not as expensive as lengthening a drive shaft. Then they shorten, they can just cut some of the tube off. When they lengthen they have to re-tube. That is when it is more expensive. If you find a long one you can easily get it shortened and balanced.
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crap, so what your saying if can find a one pc driveshaft longer than 59.5in then I can just have it cut to fit. and balanced.
is there a particular DS to choose? is there one heavier duty than another? I know someone has done this before what did you use?
I just got the cooling system sorted out and got the alt. pigtail ordered and im about ready to get the headers and take it down the road to check everything else.
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Your current set up never came in a truck with a 1 piece drive shaft. 1977 should have had a 12 bolt rear as well. All TH400 that had the fixed yoke that the u-joint was fastened to had a 2 piece in a 2 wheel drive. You will need to have one made with a slip joint in it like what was in my 72 K20 rear.
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Gotta have a slip joint
Either in the back of the Trans or in the shaft
Find a suitable used one that's too long
Take careful measurements
And take the shaft to a shop and have it shortened
Lot cheaper than having a brand new one made
Unless the used one you buy has worn out slip joint splines
Don't worry about the size of the U joint yokes on the shaft
Any shop will have combination joints to match the shaft yoke and the axle yoke
Easiest thing is just have your truck towed to a driveshaft shop and have a new one made to fit
Very common , I've had a new shaft made for almost every engine or Trans swap
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Ok, i'm sorry b/c I kno my ???'s arent super clear so let me try to get this straight in my head. I just had a convo with my dad. He has a 76 custom deluxe i6 that he is snatching motor out of and putting into a 78 long bed body he will not need both DS of course. So I (if the DS is over 60”) asked him if I could get the DS and then just get it cut to fit. He said yes.
Reading what you just wrote it sounds as If I should have made a better descision on what tranny and tailshaft I was going to need b4 just running out to jump on the first th400 I seen, but since I have this one can I:
get the slip on yoke cut off the donor DS (since it more than likley wont have the same spline count) and have my bolt on yoke welded onto the donor DS (since it already has the proper spline count) and just not use the bolt in the middle of the yoke after of course it has been measured and cut to the correct length?
So far the part I thought was going to easy is the hardest and the part of the swap I thought was going to be hard was easy as pie. https://www.youtube.com/watch?v=p5TUX3EThkk
Edit: just read roundhouse reply sounds like my plan wont work so I'm going to count the splines on my dads and pray its perfect then just cut weld and balance. if not the same number then its back on the hunt. thx
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The th400 is 32 spline th350 700r4 are 27 sm465 are 10 or 32 depending on the year. If you have a slip yoke you can swap it to any driveshaft. Likewise if you have two price shaft. To shorten one isn't hard you con do it with a gender and welder. Then if you have to get it balanced. Just have take your time.
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If I remember correctly..I think 59.5 is the length of the shaft on a shortbed with a 350 tranny. It would just need the right slipyoke.
I used an aluminum police crown Vic shaft fit perfect.
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th350 can have 3 different tailshafts
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my dad is giving me his 67in driveshaft and I bought a 32 spline slip on yoke off ebay but I just got it today and they had it listed as new, but I checked it and it has 3 splines chewed in a small spot about halfway down the shaft. can it be saved? or?
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Did you ever get the Th400 going in your short bed?? Kind of in the same boat right now. Any info would be appreciated.
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Yes, as a matter of fact the frame already had the proper holes pre-drilled. So all I had to do is drop it in and make sure it was lined up. Once I got the tranny mount bolted in place everything hooked up and truck drives fine. Now its on to the true dual cherry bomb vortex 2.5in. tips, full tune, brake booster install, and 3:73 gears and posi., all new suspension, big block coil springs, new oak bed kit, wheels, tires, dash wrap, then body work and paint. Whew!!!!!!!
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Sounds like fun! Did you use the original drive shaft? Was it the right length? Did you convert the tranny to slip yoke? From what I've gathered the 4inch tail th400 will be a tad shorter than the th350 long tail or 700r4. The cross member and mount I'm not too worried about. The th400 I have has a bolt on yoke. Truck is a 86 C10 Silverado 2wd swb fleet side. Really did want to use this th400 behind the bbc I recently finished.
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Converted over to slip on and had to get the donor ds shortened to 59.5" center of yoke to center of yoke. Original tranny was th350 behind a 305v8, no way it stand up behind my bbc for long if I played with it. Which I AM. Lol. Hey best of luck to with ur build. Hope u have fun. Im hope to stroke mine out in the future to a 496 and have some reL fun. Th400 was several inches long err r which is why the tranny mount had to be moved towards reRend. But again the frame bolts were pre-drilled from factory in anticipation of possible engine/tranny swap. #sohappyitwas.
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http://www.dennysdriveshaft.com/p69_t_400_4l80_4l85_transmission_1310_slip_yoke_for_use_on_truck.html
If im not mistaken this was the proper part # of my yoke. Have fun!
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Hey thanks for the info and part #! Guess I'll get to ordering. I'll let you know how it all goes back together in a few weeks.
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Kool have fun. Unleash the beast!!!!!!!!!!!!!!!