Measuring drive shaft
- Thread starter Johnny
- Start date
Keeper
Active Member
I cheated. When I did mine, I took pictures of mine with the tape measure. Then i printed them and took them to the driveshaft shop!
Of course your measurements will be different, but it sure helped the guying making my driveshaft!
As for weight, you could always pile some weight on the back of the frame to see how much it changes, don't think it will be much.
Of course your measurements will be different, but it sure helped the guying making my driveshaft!
As for weight, you could always pile some weight on the back of the frame to see how much it changes, don't think it will be much.
Screaming Metal
Active Member
As your rear springs compress, your trans yoke will slide into the transmission. If your gonna have a driveshaft made, measure from the centerline of the rear universal to the tailshaft seal or the output shaft.
The way I do it is lay on the creeper, slide the yoke into trans in all the way, hold the rear of the driveshaft up, measure from the cross to where it bolts up to the front, that cl dimension. If its too short, I measure CL to CL, then subtract 3/4.
If its too long, I measure where the rear yoke CL is compared to where the CL of the rear cross on the driveshaft, write down that dimension, MINUS 3/4".
Both these measurements are with the trans. slip yoke all the way up into the trans.
YOU DO NOT WANT THINGS STACKING UP SOLID AS YOUR REAR SUSPENSION COMPRESSES!
The way I do it is lay on the creeper, slide the yoke into trans in all the way, hold the rear of the driveshaft up, measure from the cross to where it bolts up to the front, that cl dimension. If its too short, I measure CL to CL, then subtract 3/4.
If its too long, I measure where the rear yoke CL is compared to where the CL of the rear cross on the driveshaft, write down that dimension, MINUS 3/4".
Both these measurements are with the trans. slip yoke all the way up into the trans.
YOU DO NOT WANT THINGS STACKING UP SOLID AS YOUR REAR SUSPENSION COMPRESSES!
Screaming Metal
Active Member
Its usually OK to do it while the car has its weight on it. just make sure your not bottomed out.
Screaming Metal
Active Member
As long as the drive shaft installs and you can pull it back to seat it in the rear yoke....your good.... if your body and other stuff is over several hundred pound, I'd say install it before you measure....better to be safe than sorry.
I've seen some dimensions hardly change then go to a 4 link w/panhard bar and really nice coilovers,and it'd change about 5/8's to 11/16's.
I've seen some dimensions hardly change then go to a 4 link w/panhard bar and really nice coilovers,and it'd change about 5/8's to 11/16's.
2old2fast
Active Member
In saying that the trans. to pinion distance will decrease as the rear of the car lowers is ASSuming that the trans is higher than the pinion to start. If the trans is below or even w/ the pinion to start , then the distance will increase as the rear of the car lowers.. just to be clear... dave
donsrods
Member
I laughed at a buddy of mine who had to have a driveshaft cut for his Olds 3 times because he measured wrong twice. Then I had one built for my Jeep pickup that I swapped a 5.0 Mustang into and it was up on jackstands with the wheels hanging free. Yep, when I got the new shaft back it was too long and I had to have it cut again. 
Now the driveline shop just tells me to set the car down on the ground with all the weight on it and measure from the tip of the tailshaft to the inside of the round spot where the yoke goes and he takes it from there. The last 5 or 6 shafts have been right, so that is what I will do from now on.
Don
Now the driveline shop just tells me to set the car down on the ground with all the weight on it and measure from the tip of the tailshaft to the inside of the round spot where the yoke goes and he takes it from there. The last 5 or 6 shafts have been right, so that is what I will do from now on.
Don
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