Drive shaft question

[ChopperCity256]

I've got a 67. Came factory with a three on tree. I've got a 700r4 going back in it. I was wondering if I am going to have to shorten the drive shaft or not or would it bolt right up?....
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[clinebarger]

The driveshaft will need to be shortened.

[gysgtc]

I have the 700 in my 67 long bed. Drive shaft is at the shop right now being shortened 3". Waiting on my billet carrier bearing from CPP to be delivered today so can have the shop press it on and get the d/s in. You will have to measure once you install the new tranny.

[ChopperCity256]

Thanks for the info!

[cdowns]

best way is to measure for yourself

that way you should only have to do the job once

[storm9c1]

Originally Posted by cdowns

best way is to measure for yourself

that way you should only have to do the job once

If you measure it yourself, make sure you ask the guy cutting it how he wants you to measure it! You need to make sure both folks are on the same page. Some want it measured end to end center line on the bearing cups, some want it measured to the center line of the carrier/support bearing, etc.

[WORP67]

If you are good at fabrication and welding then its not hard to shorten your shaft. If you cut everything right, measure right, and tack weld and test fit then you should be good. I have done prob almost a dozen. They where on trail rigs but half of them where driven to and from the trails. Never had any vibration probs and you can balance them a few ways if you need. I had some old school guys tell me yo find where and how much weight it needs you can put hose clamps on them and drive see if it helps or makes it worse then move and try again. The guy I knew back in TN that made shafts would spin them on a lathe and hit them with a torch or liquid nitrogen to get them to spin true. He told me he never understood why people messed with balancing unless they where way out cause the heat of your exhaust was enough to warp a shift. The heat from the pipes/muffler would push or pull on the shaft as it sat and cooled or in traffic jams, etc.

[clinebarger]

Originally Posted by WORP67

If you are good at fabrication and welding then its not hard to shorten your shaft. If you cut everything right, measure right, and tack weld and test fit then you should be good. I have done prob almost a dozen. They where on trail rigs but half of them where driven to and from the trails. Never had any vibration probs and you can balance them a few ways if you need. I had some old school guys tell me yo find where and how much weight it needs you can put hose clamps on them and drive see if it helps or makes it worse then move and try again. The guy I knew back in TN that made shafts would spin them on a lathe and hit them with a torch or liquid nitrogen to get them to spin true. He told me he never understood why people messed with balancing unless they where way out cause the heat of your exhaust was enough to warp a shift. The heat from the pipes/muffler would push or pull on the shaft as it sat and cooled or in traffic jams, etc.

This is a very good way to beat up the bushings in the transmission or ruin a pinion bearing.

Have a driveline built & balanced by a driveline shop......Especially with a O/D trans...You may lower the engine RPM but the driveshaft speed stays the same!

[storm9c1]

^^^^ I agree.

I had mine done by a local truck driveline shop for about $80 ($39 shortened and $39 balanced). I also paid a little extra to have the carrier/support bearing replaced at the same time since my C30 has a 3-piece. They used a much heavier bearing than what came on there. They had it all done in 2 hours. Very happy. I couldn't have beat that even if I was an expert welder (time, materials, and frustration).

Good thing too -- they found that the drive shaft was originally messed with once before and done wrong by a similar "do it yourselfer". Even though it was somewhat balanced, the yoke was welded on crooked as heck. He actually called me about 15 minutes into the job and asked me if I did that and if it vibrated. I laughed and said, nope, I didn't do it and no, luckily it didn't vibrate. The balance must have been close enough. But I certainly told him to fix it. No wonder my old support bearing and trans output seal was destroyed. I changed the trans from a TH400 to 4L80E at the same time, so I never did determine if the trans was internally damaged.

[clinebarger]

Originally Posted by storm9c1

^^^^ I agree.

I had mine done by a local truck driveline shop for about $80 ($39 shortened and $39 balanced). I also paid a little extra to have the carrier/support bearing replaced at the same time since my C30 has a 3-piece. They used a much heavier bearing than what came on there. They had it all done in 2 hours. Very happy. I couldn't have beat that even if I was an expert welder (time, materials, and frustration).

Good thing too -- they found that the drive shaft was originally messed with once before and done wrong by a similar "do it yourselfer". Even though it was somewhat balanced, the yoke was welded on crooked as heck. He actually called me about 15 minutes into the job and asked me if I did that and if it vibrated. I laughed and said, nope, I didn't do it and no, luckily it didn't vibrate. The balance must have been close enough. But I certainly told him to fix it. No wonder my old support bearing and trans output seal was destroyed. I changed the trans from a TH400 to 4L80E at the same time, so I never did determine if the trans was internally damaged.

On a 2/3 piece, You can get away the front joint being clocked wrong, If the front driveline is level/No u-joint angle.

[truckdude239]

It will need to be shortned now a th350 with the 6inch tail shaft will bolt right in