:? Recently changed over to parabolic springs and am getting an irritating vibration that really doesn't go away right up to 55 mph. The springs have changed the height of the rear of the vehicle by approxematly 2 inches. Is it possible that I need to shim the rear springs to bring the nose of the diff up.
I've had the drive shaft out and there is no free play or any other problem with it that I can detect. Any worthwhile advice would be appreciated.
Cheers
Derek
'82 Airportable.
Lots of vibration.
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DaveB
- Defender of the World
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- Joined: Mon Feb 09, 2004 7:45 pm
- Location: Vernon, BC
Hi Derek,
Does it make any difference if you freshly grease the yolk of the rear driveshaft? I found that my height increase put a bit of extra stress on the yolk, and when its freshly greased it doesn't vibrate, but when the grease has worked its way out it begins to vibrate a little, but only immediately when I'm on or off the throttle.
I took it to Pat's Driveline over here. They have a laser levelling tool for checking drivetrain components. They told me that the shaft will continue to have the vibration until I drop the back of the transmission down by one inch as this is where the angle is too steep. I also put in 4degree shims between the asle and the springs, which didn't hurt either. Next time I'd go 6 degrees though as 4 doesn't make a huge difference.
Dave
Does it make any difference if you freshly grease the yolk of the rear driveshaft? I found that my height increase put a bit of extra stress on the yolk, and when its freshly greased it doesn't vibrate, but when the grease has worked its way out it begins to vibrate a little, but only immediately when I'm on or off the throttle.
I took it to Pat's Driveline over here. They have a laser levelling tool for checking drivetrain components. They told me that the shaft will continue to have the vibration until I drop the back of the transmission down by one inch as this is where the angle is too steep. I also put in 4degree shims between the asle and the springs, which didn't hurt either. Next time I'd go 6 degrees though as 4 doesn't make a huge difference.
Dave
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derek n
same as post
Thanks Dave. Freshly greasing the driveshaft doesn't change anything. The vibration is constant right up to 55 mph. There is no change on acceleration or deceleration. I took some measurements tonight with the help of a degree wheel. There is 2 degrees difference between the transmission and the diff. The drive shaft is sitting at 14 degees. So if I'm thinking in the right direction, and please bare with me, I should shim the front of the diff to bring up the nose and therefore reduce the angle of the drive shaft, therefore allowing the joints to move more freely. And hopefully reduce vibration. To actually put the faces of the transmission and diff in parrallel I would have to shim the nose of the diff down. This would increase the angle of the drive shaft therefore increasing the binding on the joint and increase vibration. I hope this is making sense.
You stated that you used 4 degrees of shims. Did this reduce any of the vibration?. You also said you would go 6 degrees. Is this a recomendation from the drive line shop?
I actually took the rear drive shaft out and went for a drive just to make sure that I'm looking in the right direction. Crystal!!! Absolutely no vibration at all. So now I know that there is no vibration when the rear drive shaft is absent.(whoopdee!!!) Along with the shims would it be prudent to change the u-joints even though they apear to be in good shape?
Cheers
Derek
'82 Airportable :?
You stated that you used 4 degrees of shims. Did this reduce any of the vibration?. You also said you would go 6 degrees. Is this a recomendation from the drive line shop?
I actually took the rear drive shaft out and went for a drive just to make sure that I'm looking in the right direction. Crystal!!! Absolutely no vibration at all. So now I know that there is no vibration when the rear drive shaft is absent.(whoopdee!!!) Along with the shims would it be prudent to change the u-joints even though they apear to be in good shape?
Cheers
Derek
'82 Airportable :?
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ANDYD
- Defender of the World
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- Location: Sunny Steveston BC
Vibration from the driveshaft.
This may be an obvious observation, but just thought I'd mention it;
Was the driveshaft removed & replaced before the vibration started?
If yes, did you re-install the driveshaft the right way around? If they have been worn in for many years one way around, then they are put in the other way around that they can vibrate?
Just a thought,
Andy :D
Was the driveshaft removed & replaced before the vibration started?
If yes, did you re-install the driveshaft the right way around? If they have been worn in for many years one way around, then they are put in the other way around that they can vibrate?
Just a thought,
Andy :D
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bclandrover
- Out of Africa
- Posts: 401
- Joined: Wed Feb 25, 2004 11:21 pm
- Location: North Vancouver
- Contact:
Driveshaft phasing and angles
Hello,
A standard universal joint driveshaft must have transmission output flange face absolutely parallel to the different input flange. As a u-joint driveshaft turns the shaft speeds up and slows down and one u-joint cancels out the other.
So, being parallel is way more important than less total angle. If you cannot stay parallel while keeping the u-joints from binding than you may have to get a driveshaft with better u-joint clearance, get a constant velosity (CV) joint type driveshaft or as a last result lower the transmission.
I have parabolics and a stock driveshaft without much vibration. :D :D I go through u-joints every couple years because of the extra strain. If I were you, I'd look at overall driveshaft condition before messing about with diff angles or transmission angles.
Are the splines wornout and being stretched slightly longer excentuating the wear?
Is the driveshaft phased correctly?
Do the u-joints only seem ok when tested by hand?
Is the driveshaft still balanced?
Later,
Don MacDonald
A standard universal joint driveshaft must have transmission output flange face absolutely parallel to the different input flange. As a u-joint driveshaft turns the shaft speeds up and slows down and one u-joint cancels out the other.
So, being parallel is way more important than less total angle. If you cannot stay parallel while keeping the u-joints from binding than you may have to get a driveshaft with better u-joint clearance, get a constant velosity (CV) joint type driveshaft or as a last result lower the transmission.
I have parabolics and a stock driveshaft without much vibration. :D :D I go through u-joints every couple years because of the extra strain. If I were you, I'd look at overall driveshaft condition before messing about with diff angles or transmission angles.
Are the splines wornout and being stretched slightly longer excentuating the wear?
Is the driveshaft phased correctly?
Do the u-joints only seem ok when tested by hand?
Is the driveshaft still balanced?
Later,
Don MacDonald