I had a driveshaft made and with it fully pushed into the 727 it barely fit into the differential saddle. I know the shaft is too long. How much room should there be between the yoke fully pushed into the trans and the rear U-joint saddle?
Driveshaft: how much clearance?
- Thread starter Ricks70Duster340
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mopowers
Well-Known Member
My driveline shop advises .75" - 1".
mopowers
Well-Known Member
I put the yoke bottomed out in the transmission and slide it out .75" - 1". Then measure between u-joint centers (front and rear). That's the shaft length you want. I've bought my last four from a local driveline shop. The last one I got was 3" x .083 DOM tube and was right at $250 w/ new ends and spicer u-joints.
Professor Fate
Push the button, Max...
About 3/4".
Did you measure it with the weight of the car on the rear suspension, or with it hanging?
Were you trying to install it with the weight on the suspension, or with it hanging?
You may not get it in with suspension compressed even with the correct length shaft- depending on the yokes used, it's gonna be real tight. Let the suspension drop and it should pop right in.
Did you measure it with the weight of the car on the rear suspension, or with it hanging?
Were you trying to install it with the weight on the suspension, or with it hanging?
You may not get it in with suspension compressed even with the correct length shaft- depending on the yokes used, it's gonna be real tight. Let the suspension drop and it should pop right in.
MOPAROFFICIAL
If it has tits, it's a liabilititty.
You definitely want more than that, .75-1 is accurate.
Once you drop it down and that suspension starts moving that ****** is going to bottom out dude
Once you drop it down and that suspension starts moving that ****** is going to bottom out dude
mopar head
DoD nuisance Alien/Squatch extermination team
If U-joints included, that`s a steal for these days, especially Cali.
dennys,empire,ect,dont measure that way
with the suspenion loaded.they measure from the face of the yoke to the end of the output shaft.and also the depth of the spline.
MOPAROFFICIAL
If it has tits, it's a liabilititty.
My shop measures with the suspension loaded too, stationary. End of the output shaft to the flat of the yoke
mopowers
Well-Known Member
Plenty of ways to skin a cat for sure. I think if you have the yoke you want to use, measuring center to center of the u-joint is good. If you don't then the mail order places do the math for ya. Not a big deal either way.
In my cars, suspension loaded vs full droop is a difference of 1/8". So, not really enough to worry about with an inch of clearance built in.
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65TerrorCuda
Well-Known Member
Shop here wanted $100 just to balance check a shaft. I'd rather put that towards a brand new one.
TT5.9mag
Two atmospheres are better than one
It doesn’t matter how you measure. As long as you measure exactly how the the guy that is building the driveshaft asks you to measure. Just like pushrods. But you need more slip than basically zero for suspension movement or you’ll junk the trans.
mopar head
DoD nuisance Alien/Squatch extermination team
I shortened a shaft- custom length for the old Dodge I built, hoping to luck out. It talked to me above 60-65 mph, so I finally got it balanced, plus straightened for a little less than that. Soooo nice to get above 70 without cringing
65TerrorCuda
Well-Known Member
Sounds like you did a pretty dang good job. Mine gets fussy more like half that speedI shortened a shaft- custom length for the old Dodge I built, hoping to luck out. It talked to me above 60-65 mph, so I finally got it balanced, plus straightened for a little less than that. Soooo nice to get above 70 without cringing
thats a real bargain
Measured from the end of the tailshaft to the flat on the diff yoke (edit: with tires on the ground). Took the shaft back to the driveshaft place today so they could cut about 1/2" off. When the rear u-joint is in the saddle, the front yoke is only about 1/4" away from bottoming out. Not sure if I mismeasured or if the driveshaft place did. No biggie, they'll fix it. Thanks for all the replies.
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Also, consider the application. What are you doing with the car? Look up critical speed for driceshafts. For my Charger, due to length and RPM, I need to go to 4" aluminum in order to be in the safety range. Too many people do not consider intended use changes everything.
Mine is from PST. 1350 yokes from Cass at Dr Diff
Mine is from PST. 1350 yokes from Cass at Dr Diff
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^^^ this.
this. and i cannot stress is enough: ask them how they want it measured. and then be specific with who you're talking to.
i had a driveline place that one guy would want them measured one way, and the other would want them a completely different way.
Agree completely. I asked them how they wanted me to measure then I provided those measurements. Did that directly to the owner through a phone call, though don't know if he was the one to make the shaft... doubt it. Possibly something was lost in the translation.
Could be. PST, when talking with them, needed to know the manufacturer of the yokes, then had me send him the front yoke so that had it and installed it right away.
This local shop has been doing driveshafts for many decades & I've never had an issue until now. The owner is very knowledgeable and I've used them for many car projects. They supplied the front & rear parts of the driveshaft too.
I have always built my own . Always cut the rear to shorten. Less chances of vibration. Never had issues. Shortened one for my son's drag car that run in the 11s at 115 mph. Never had an issue.
Lots of variables. I went with 1350 u-joints and noticed that the slip yoke from Strange was shorter than the stock one, so less spline engagement. Of course the stock tailshaft seal had a boot on it, so I decided to go with a seal with no boot. Final clearance was 1 inch.
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