Cutting Driveshaft

[Rmoore45]

I'm installing a T-5 into my '67 coupe, I got to the point where I have to put in the driveshaft. Its too long How do I go about measuring so that I can get it cut?

 

[2+2GT]

Interesting. At least 90% of the time no cutting is required. Welcome to that 10%.

Put the back end of the car on jack stands with the axle hanging all the way down, tires in the air. insert the slip yoke all the way in the trans, then pull back out 1/4". Measure the center of the front U joint cap to the center of the rear joint cap.

 

[Rmoore45]

I put it on my lift and had the yoke stick out 1/4", from center to center it was 50 and 3/8". My driveshaft is 51", 5/8" too big.

 

[zookeeper]

Interesting. At least 90% of the time no cutting is required. Welcome to that 10%.

Put the back end of the car on jack stands with the axle hanging all the way down, tires in the air. insert the slip yoke all the way in the trans, then pull back out 1/4". Measure the center of the front U joint cap to the center of the rear joint cap.

If you measure it that way (full droop) when the suspension compresses, you're drive shaft is quite likely to go into the trans too far, bottoming it out and damaging the trans. I always measure it with the axle stands under the axle so the springs support the car's weight. BTW, the T5 is about 3/4" longer from block to seal, so while you may be safe with 5/8" off your stocker, better measure at least twice.

 

[Rmoore45]

If you measure it that way (full droop) when the suspension compresses, you're drive shaft is quite likely to go into the trans too far, bottoming it out and damaging the trans. I always measure it with the axle stands under the axle so the springs support the car's weight. BTW, the T5 is about 3/4" longer from block to seal, so while you may be safe with 5/8" off your stocker, better measure at least twice.

I also thought that if I measure with full droop that when its back on the ground the driveshaft would actually go into the trans, however that's not the case. With the car on the lift (full droop), I measured the distance between the T-5 seal and the pinion yoke and got 53". Then I put the car on the ground and bounced it around and let it settle down, I took the same measurement and got 53 and 1/2". So the axle actually moves further away from the trans as the suspension compresses because of how the leaf springs are attached to the car. I thought that was pretty cool when I measured it and figured out how it worked.

I was thinking about just rounding up to make it easier and just cut 3/4", now that I know the trans is 3/4" longer I probably will. Thanks

 

[2+2GT]

If you measure it that way (full droop) when the suspension compresses, you're drive shaft is quite likely to go into the trans too far, bottoming it out and damaging the trans. I always measure it with the axle stands under the axle so the springs support the car's weight. BTW, the T5 is about 3/4" longer from block to seal, so while you may be safe with 5/8" off your stocker, better measure at least twice.

Rmoore is right, the yoke slides OUT of the trans as the suspension compresses.