Driveshaft length for th400 & Ford 9"???

[KevinB]

Anyone know? My engine is not in the car yet so I cann't get the measurement yet. I would like to get one made or at least ordered soon.


Thanks.

 

[FastRegalWE2]

Im doing the TH400 swap now, Im not sure on the 9" but from what I have read, only some cars need 1/2" taken out of the driveshaft to run the TH400 and some dont. Im hoping Im one that doesnt

 

[yullose]

If I were you, I'd wait 'till it's all together before having one made.

My car was all together and I still fvcked up the measurement.
Thankfully, my driveshaft shop is flexible and they fixed it (shortened it) for me for free.

 

[FastRegalWE2]

If I were you, I'd wait 'till it's all together before having one made.

My car was all together and I still fvcked up the measurement.
Thankfully, my driveshaft shop is flexible and they fixed it (shortened it) for me for free.

you on a 9" or stock rear, how much did you have to have cut?

 

[yullose]

you on a 9" or stock rear, how much did you have to have cut?

Stock rear...
I don't trust the stock shafts, and neither did my driveshaft builder. He insisted on a fresh 3" shaft.
I watched one spit out while standing next to a car on a chassis dyno... The front U-joint caps hit my boots.

If I recall correctly, the 9" has different length yokes available, and the pinion snout is a tad shorter than a conventional style rear. You may get away without having to cut anything if you trust the stock shaft enough to re-use it.

Here's a post from a few months back regarding the TH400 / driveshaft swap.

http://www.turbobuick.com/forums/transmission-talk/195750-th400-conversion-driveshaft-pics.html

 

[FastRegalWE2]

Stock rear...
I don't trust the stock shafts, and neither did my driveshaft builder. He insisted on a fresh 3" shaft.
I watched one spit out while standing next to a car on a chassis dyno... The front U-joint caps hit my boots.

If I recall correctly, the 9" has different length yokes available, and the pinion snout is a tad shorter than a conventional style rear. You may get away without having to cut anything if you trust the stock shaft enough to re-use it.

Im running a 3.5" aluminum driveshaft, I just read that it might not need to be cut

 

[yullose]

The trannys are almost exactly the same length, but the problem is,TH400 yokes are so much beefier, they tend to push the U-joints further back.

Here's a good example... I took this pic of my two shafts side by side.
The difference is pretty obvious.

 

[turbodave231]

Don't order your driveshaft until you have the axle installed. The yoke on the center section can vary in length depending on brand.

You want to measure with the car at the ride height you plan to use. Adjustable upper control arms will also change the driveshaft lenght.

I got my driveshaft from DynoTech. They specialize in driveshafts. I got a
3.5" chromoly shaft with 1350 solid u-joints and a yoke for just under $400.

DynoTech will supply a form with measuring instructions. If you follow the instructions, its kinda hard to frick it up.

 

[KevinB]

Thanks guys! Sounds like a good idea to wait.

 

[MIB]

I can tell you this, I had to cut mine when I replaced my 200 w/400 using the 9 inch rear. Make sure you measure on the ground at ride height. Place the yoke you are going use in the tailshaft all the way then measure from the center of your yokes. I then removed 1/2" from measurement no more 3/4" for slip.