One piece drive shaft??

[starfire58]

Has anybody installed a one piece driveshaft in their truck. If so, what driveshaft did you use and does this work well? I have a '71 that I'm working on and just rebuilt the suspension and lowered it 2"/4" and now I'm working on the drivetrain. I just wondered if a one piece shaft was possible to do easily.

[Lee H]

Long or short bed? Many, many people have done this on short beds. Very easy. With a drop and a one piece shaft you will more than likely have to adjust the pinion angle.
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[starfire58]

My truck is a longbed. I guess I should have mentioned that.

[brad_man_72]

I've built quite a few one piece drivelines for lowered lwb 67-72s no problem. I build them from new parts usually, using spicer joints and ballance them. All you have to do is take your trans yoke into a driveline shop (saves you some money) and give them a tailshaft to center of rear ujoint measurement.
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[bigdog1985]

Just had one built for my truck. Picked up a drive shaft for 75 out of an Astro van and had to lengthen it 2.5 inches. Longbed with 700r4. Previously had a 400 and a one piece. Had a local shop built the shaft to my measurements. He would lengthen, but was more than willing to shorten the Astro van shaft.

Hope this helps.

[ecgate]

Bradman. Just curious how much it costs to have a one piece drive shaft made for a 67 shortbed. And are there any other mods you have to make to the truck? Example= mess with the angle of the pinion gear. Or is it a drop in with no mods.

[bigdog1985]

I bought the one piece shaft out of an Astro van 89 I think. I put it in the truck and measured the total length I needed. Took it to a d-line shop and they installed the yoke with new ujoints and shortened the length to perfection for $125.00

[ecgate]

That seems like a fair price bigdog. Its something im going to look into.

[starfire58]

Originally Posted by bigdog1985

Just had one built for my truck. Picked up a drive shaft for 75 out of an Astro van and had to lengthen it 2.5 inches. Longbed with 700r4. Previously had a 400 and a one piece. Had a local shop built the shaft to my measurements. He would lengthen, but was more than willing to shorten the Astro van shaft.

Hope this helps.

bigdog1985- Do you still have the one piece for the TH400? If so, can you let me know the specs on it, as that is exactly what I need. I'm installing a TH400 in my truck. Or, if you do have it and wish to sell it let me know. Is your truck lowered? Any changes to pinion angle required?

[starfire58]

Anybody know what the length difference is in a driveshaft for a TH350 vs. TH400? Is there a difference? Both my TH350 that was originally in truck and my rebuilt 400 are short tailshafts.

[crazy longhorn]

Originally Posted by starfire58

Anybody know what the length difference is in a driveshaft for a TH350 vs. TH400? Is there a difference? Both my TH350 that was originally in truck and my rebuilt 400 are short tailshafts.

The 400 , should be 11/16" longer, & also uses a larger slip yolk. You will also find the trans mount farther back on the 400. Check dimentions. www.tciauto.com ....go trans dimentions

[dukcaln]

Originally Posted by crazy longhorn

The 400 , should be 11/16" longer, & also uses a larger slip yolk. You will also find the trans mount farther back on the 400. Check dimentions. www.tciauto.com ....go trans dimentions

from what I just went through, the measurement for mine a 72 lb, swap the TH350 for TH400, was moving the crossmember back and then 70" from middle of the front ujoint to middle of the rear.... plus the TH400 slip yoke. for me, I was able to use my same two piece but add the TH400 yoke to the end and it worked

[Flint70step]

In my 72 Burb I used an aluminum drive shaft out of an extended cab mid 90's chevy truck.I have a 4L80E trans so the yoke worked out just fine.I removed the carrier bearing and ground down the rivets and hammered off the CB bracket.Had Austin Drivetrain shorten the shaft for 125 I think.The only other thing I had to do is order a u-joint for 1350 series to 12 bolt chevy.Worked great! and I have a lightweight,strong cool looking drive shaft.I found the drive shaft in a pile at a friends house and traded a sixer for it

[brad_man_72]

Originally Posted by ecgate

Bradman. Just curious how much it costs to have a one piece drive shaft made for a 67 shortbed. And are there any other mods you have to make to the truck? Example= mess with the angle of the pinion gear. Or is it a drop in with no mods.

I want to say its about $150 for everything new. If you have a good trans yoke the price drops quite a bit.

So you can see its really not worth it to drive around and buy a used shaft for $50 then spend another $100 having it shortened and ballanced, Assuming the weld yokes are useable.

I noticed somebody using an aluminum shaft, those are usually too large in diameter to use in a 2wd 67-72 and theirs no way id use one on a 4wd that ever sees dirt as many aluminum shafts are so thin you can dent them by standing on them. But they do look cool in a show truck.
I also wouldn't use aluminum for a drag car with slicks, because just like aluminum connecting rods they will flex and eventually become brittle and break, so they need to be replaced every season or so.

Remember when you change trans yokes on a driveshaft you should have the shaft re ballanced. Individual parts aren't ballanced and the machining process for where the ujoint is held isn't perfect, meaning the shaft will not run true and have a vibration. Ballancing the entire shaft as an assembly is the best way to prevent premature wear and failure of parts.
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[bigdog1985]

Sorry Starfire I haven't been on in a few days. I will measure the shaft and post it soon.

Truck is not lowered at this time, however I think I will be fine until I drop it below the 4/6 from what I have read.

I will sale the shaft, not sure how to get it to you. PM me to work out the details.

C

[dukcaln]

I had no idea that if you changed the yoke, say from the TH350 to the TH400 yoke that you need to re-balance the DL!

[brad_man_72]

Originally Posted by dukcaln

I had no idea that if you changed the yoke, say from the TH350 to the TH400 yoke that you need to re-balance the DL!

Even if you go from one th350 yoke to another th350 yoke you should re-ballance.
Or if you change ujoints and don't mark the yoke (you can put it on 180* out) you should re-ballance.
........ changing just the ujoints WILL change the ballance of a shaft. Especially if using a precision or house brand ujoint. Once you shim all of the endplay out of the joint and set the keepers properly the joint won't be centered in the yoke or at least not in the exact same spot as the ujoint that was in the shaft when it was ballanced.

If you paint/get undercoating on your driveshaft it can upset the ballance of the driveshaft.

pretty much any time you modify a driveshaft it needs to be reballanced.
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[starfire58]

Thanks to everyone for the info. This site never fails to amaze me! There doesn't seem to be any questions I can't get answered. Thanks Guys! Bob

[dukcaln]

Originally Posted by starfire58

Thanks to everyone for the info. This site never fails to amaze me! There doesn't seem to be any questions I can't get answered. Thanks Guys! Bob

I agree. I have learned so much from posting and issue and getting feedback.. also from reading all the post.... amazing