Jump to content
Ultimate Subaru Message Board

Driveshaft? noise after Brat 5-speed swap


Recommended Posts

Since no one caught this in the pictures, I will point it out. First, you have a straight line down the drive shaft out of the tranny. By this, I mean if you drew a line down the tranny main shaft and continued it out, the drive shaft itself is inline with the tranny. No good. U-joints are designed to operate at an angle. Second, you have a different angle at the pinion. The output shaft and pinion angles must be within 1 degree of each other. How 'steep' they are is irrelevant up to a point. Go to Ace hardware and get a magnetic angle meter. They're like $6. Stick it to the pinion flange and record the angle. Stick it to the output shaft housing and measure that. They should be no more then 1 degree apart. If they are (and I can see they are in the pics) raise or lower the pinion or tail shaft until they are close. Remember, no straight lines.

Link to comment
Share on other sites

Since no one caught this in the pictures, I will point it out. First, you have a straight line down the drive shaft out of the tranny. By this, I mean if you drew a line down the tranny main shaft and continued it out, the drive shaft itself is inline with the tranny. No good. U-joints are designed to operate at an angle. Second, you have a different angle at the pinion. The output shaft and pinion angles must be within 1 degree of each other. How 'steep' they are is irrelevant up to a point. Go to Ace hardware and get a magnetic angle meter. They're like $6. Stick it to the pinion flange and record the angle. Stick it to the output shaft housing and measure that. They should be no more then 1 degree apart. If they are (and I can see they are in the pics) raise or lower the pinion or tail shaft until they are close. Remember, no straight lines.

 

Sorry but the "Angles within One degree stuff" is absolute miss information have a good look under many a rear axle vehicle the angles are never anywhere near equal at either end,Alignment of the cross yokes for the Uni's must be exactly the same and that is often a problem with retubed Tailshafts.

Link to comment
Share on other sites

No need to be sorry if you are incorrect. One piece drive line output and pinion angles have to be within 1 degree and the yokes must be timed properly. The angles on a two piece do not. There is a cancellation effect. Been building custom 4wds, rock crawlers and rods for 20 years. Can't tell you how many times I fixed someone else's mistakes. Get the angles wrong on a one piece and you'll get a vibration anywhere over the 40mph mark. Sorry, but reality and physics trump your misinformation theory.....

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...