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Discussion Starter · #1 ·
Hello im new to this site and i have a tail piece problem with my new trans i just bought a TH350 rebuilt tranny with 69,000 with a B&M shift Kit and B&m Torque Converter but the tail piece is only 6 inch long and my truck has the 9 inch tail piece i have read some threads or forums on this and read that i could just get a longer slip yoke ?? is this true? then if so how long do i get it 3 inches? my drive shaft is about 70' to 71 inches long ( truck is mostly stock) what should be my next move can someone please give me some advice ?
 

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My truck had a rwo piece driveshaft, and when I made the same change, I used a longer front shaft to make up the difference. I do not know of any yokes that are 3" longer, and would not trust one that long any way.
 

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I would suggest you have the out put shafts swapped out... so you have the correct 9 inch out put shaft.

I've never seen a 3 inch longer yoke for this problem
 

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You have two choices, swap output and tail housing, which requires partial dismantling of the transmission, or changing your driveshaft, which probably means having your local drive line company make one for you.

You will not find a longer yoke. To avoid vibrations the universal should be as close to the end of the output shaft as possible. The further away from the end it is, the more vibration problems you would have.
 

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There is actually a longer yoke made for the TH350 AND another for the TH400. I used a longer slip yoke in my TH350 to TH400 conversion, BUT it was on the FRONT part of a 2 piece driveline, and the front does'nt move forward/backward. I looked into having a longer shaft made to replace the 2 piece, and was told NOT to do it; they said 70" would be too long, and would also need to be 5 to 6 inches in diameter. Is that your C/C distance on the U-joints, or the total lenth WITH your slip yoke? The longer yokes are actually sold for 4 X 4 type applications with raised suspensions, and greater movement is needed.
 

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your best bet is to swap the extention housing and the output shaft.or you could get a longer yoke which isnt really the best solution.a 350 is very easy to rebuild and dismantle and with it being rebuilt it shouldnt need more that a couple gaskets,you should have no reason to dismantle the clutchepacks or mess with rubber seals.you would need a pan gasket a valve body gasket a pump gasket and a extension housing gasket,no need to touch the pistons.


if you decide you dont want to touch it just get the driveshaft redone,a driveline shop that does driveshafts can either remake the shaft or extend your current one to correct length.which im not sure the exact cost but where i live it about 120 bucks to get a longer shaft made with the existing yoke.
 

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Discussion Starter · #8 ·
Thank you all!! Driveshaft surgery?

Thank you fellas for the advice, but if i get my drive shaft redone how long should i get it 3 inch more??? since i read that tail pieces came in 6,9 and 12 right should 3 inch be fine or do i want some play in there??
 

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Deluxe10 said:
Thank you fellas for the advice, but if i get my drive shaft redone how long should i get it 3 inch more??? since i read that tail pieces came in 6,9 and 12 right should 3 inch be fine or do i want some play in there??

if you get the driveshaft redone you have to measure the difference between the old housing and the new one.also keep in consideration that the driveshaft needs room to slide in and out.a good driveline shop should only need the difference between the old and new to know what you need.also you need to specify whether the car is stock height or if its raised or lowered,both of those also affect driveline length.
 

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Sometimes, it's actually much easier to go at it from the top, to at least get them loosened with a wrench. Other than that, judicial use of extensions and u-joints. Some guys cut holes in their firewall to get at them that way, and plug the holes when they're done. You might want to put a couple of bolts back in that you already removed, helps to maintain control of the trans until it's on the trans jack. You do have the torque converter unbolted already?
 
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