extending a Drive shaft

[Dustytrix]

I have finally got my 383 th400 set in my camaro yesterday, and it looks sweet. I knew the 700r4 trans was longer than th400 making my driveshaft 2" short. Ok I have a yoke from 4l80e that is 6" long verses the standard 4" that come with the th400, and 700r4. Would that work? Or how for does the yoke have to go into tranny and how for can it stick out? Just a thought that would make it easier? :idea:

 

[grumpyvette]

as a general rule, and in an ideal world, you discuss the intended use of your drive shaft with the drive-shafts manufacturer, there usually should be between 1" -to- 1.5" of play between the fully seated yoke into the transmission and the point where the yoke actually is when the cars set up with you in the car to allow the spline some movement,your 6" long spline yoke may fit and function ,but its not likely to function correctly, or spread the torque loads on the trans tail section, or output shaft in that trans tail section, correctly with that much distance between the trans tail shaft support and the u-joints and of course the angles and balance will effect results, yes, I'm well aware its a P.I.T.A. but fabricating a longer drive shaft, that locates the u-joints and clearances and angles and spline engagement, is the preferred route to take here

keep in mind spline count on the yokes and u-joint dimensions vary a good deal in applications and the YOKES will on occasion need adapter u-joints or a custom drive shaft
you want to have a drive shaft length and diam. provide the required engagement surface area to sustain the full torque loads without the splines sustaining damage, so the spline length should be long enough to allow 3"-4" of spline engagement surface area plus that 1"-1.5" of slack/clearance, yet place the u-joint as close as possible to the transmission and its rear seal and thus reduce leverage the spinning drive shaft exerts on the output shaft and transmission rear mounts etc. you generally can,t just install a longer splined transmission yoke and get by!
BTW as the new custom drive shaft diam. is increased, so does the potential torque load capacity, and shorter shafts, of any diam. tend to handle higher loads better, than the same diam. shaft thats longer.provided the quality of the fabrication and materials remain the same
the U-joints are usually the weak link, and the 1310, and 1330 series are significantly weaker than the 1350series

links with good info

http://www.pstds.com/driveshafts_101.htm

http://www.circletrack.com/drivetrainte ... _delivery/

http://www.dennysdriveshaft.com/c8_tran ... yokes.html

http://www.dennysdriveshaft.com/c7_pini ... yokes.html

http://www.wolferacecraft.com/pinionangle.aspx

http://www.dennysdriveshaft.com/c75_general_motors.html

http://www.iedls.com/Driveshafts/Measur ... shafts.asp

http://www.driveshaftspecialist.com/Alu ... aster.html

viewtopic.php?f=71&t=754&p=1079&hilit=+loop+driveshaft#p1079

http://www.dennysdriveshaft.com/c1_nitr ... hafts.html

http://markwilliams.com/driveshafts.asp ... 2godU3o2aw

http://www.dennysdriveshaft.com/c130_un ... oints.html

 

[grumpyvette]

obviously your always fighting the tendency of a weak link in a drive train, to fail, and you goal of constantly upgrading one component just tends to make a different part the weak link, ideally ,in a correctly designed drive line ,the tires tend to spin and smoke , acting like a fuse, limiting the shock loads on the drive train, as a designed weak link ,well before the drive line tends to puke parts, on the pavement!

and
Id point out that the FORD 9" and DANA 60 rear differentials tend to be a bit stronger and more durable than the chevy 10 and 12 bolt rears in most cars, so before spending a great deal of time and effort buying aftermarket axles,gears,caries and posi units for the weaker chevy rear differentials you may want to upgrade the rear differential and save yourself some grief, in the long run if your car produces significant hp/torque

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[Dustytrix]

Thanks for getting back to me. I see what your saying about the position of the u joint putting more stress on the tranny. I will try to find a drive shaft or have one made.