Symptoms of a failing GL1500 u-joint

[grumpy]

I recently pulled the drive shaft in my GL1500 Lehman trike in order to replace the pinion seal. There is now a slight vibration, which was not present before the repair, which can be felt during acceleration but not deceleration. It is also present under constant throttle at speeds above 65-70 mph. This is a very subtle vibration, almost like a "buzzing" and is felt more through the handlebars than the floorboards. It is not the same as was felt when the front u-joint in my Valkyrie trike went bad. That was much more pronounced and was felt almost completely through the pegs and only went away at constant throttle.

The front u-joint had no slop/play in it but was very easy to move. Almost no resistance. I am 99 % sure that all the "rollers" in the rear u-joint were correctly placed and undamaged. I indexed the drive shaft upon installation. I hate to start throwing parts at this, especially at the cost of a front u-joint these days. So my question is does anyone have any suggestions as to what this could be? And any tips for diagnosing would also be appreciated. TIA, Stan

Oh, BTW I did manage to destroy the front u-joint boot & did not replace it as I didn't have time to wait for a new one to ship. Don't see how that could be relevant, but you never know.

 

[Solidbob]

I recently pulled the drive shaft in my GL1500 Lehman trike in order to replace the pinion seal. There is now a slight vibration, which was not present before the repair, which can be felt during acceleration but not deceleration. It is also present under constant throttle at speeds above 65-70 mph. This is a very subtle vibration, almost like a "buzzing" and is felt more through the handlebars than the floorboards. It is not the same as was felt when the front u-joint in my Valkyrie trike went bad. That was much more pronounced and was felt almost completely through the pegs and only went away at constant throttle. The front u-joint had no slop/play in it but was very easy to move. Almost no resistance. I am 99 % sure that all the "rollers" in the rear u-joint were correctly placed and undamaged. I indexed the drive shaft upon installation. I hate to start throwing parts at this, especially at the cost of a front u-joint these days. So my question is does anyone have any suggestions as to what this could be? And any tips for diagnosing would also be appreciated. TIA, Stan

When you pulled the drive shaft did you put it back in the exact same direction / on the same U-Joint Straps ..... Drive shafts are generally balanced, but not balanced with U-Joints... if you changed out U-Joints with ones with Zerk Ftgs that will cause a minor out of balance situation sometimes even the side of Nuts vs Straps on the U-Joints.... the pinion seal doesn't move. So its something you removed and replaced...... Just my guess.....

 

[grumpy]

Solidbob-
I didn't replace any parts of the drive line, only the pinion seal. I don't know if I assembled the rear u-joint with the straps/nuts on the same side. Also don't know if the cross was put back exactly the way it came out. Guess I didn't think it mattered that much. Another thought that has crossed my mind, could improper/uneven torque on the strap nuts be a possibility?

 

[Solidbob]

Solidbob-
I didn't replace any parts of the drive line, only the pinion seal. I don't know if I assembled the rear u-joint with the straps/nuts on the same side. Also don't know if the cross was put back exactly the way it came out. Guess I didn't think it mattered that much. Another thought that has crossed my mind, could improper/uneven torque on the strap nuts be a possibility?

Torque would not matter, but you might try moving the straps 180 degrees and see if that changes anything..... as long as torque is at recommended settings and tighten in a criss-cross pattern until tight then torque down in the same pattern just a little all the way around / usually U-Joints are not a problem but on a trike as we feel everything that vibrates it could be and if everything feels tight I'm at a loss...... sorry...

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[eastkytriker]

I don't know if your Lehman is like a Motortrike but on my motortrike the front yoke always falls off when you slide the driveshaft out and when it goes back together it has to be lined up in reference with the rear joint. If not aligned properly you will have a very bad vibration (dont ask me how I know) There used to be a thread on here showing a pic of a motortrike driveline with proper line up. Just a thought.

 

[grumpy]

easytriker
Thanks for the reply. I did line up the two u-joints, but they could be 180* out from their original position. I will pull the drive shaft & rotate the front joint 180 & swap the straps on the rear joint as Solidbob suggested & see if that makes it go away. If that doesn't do it, I guess a new front u-joint is the next thing unless someone else comes up with another possibility.

 

[Ozarkryder]

The u-joints should be lined up with each other, but they dont always exactly balance that way. On the tranny end of the driveshaft the splines into the trans could be off one spline in one direction or another and cause a vibration as you described.

 

[cantom]

A pinion seal is what the Lehman Goldwing 1500 I'm buying needs.

Is this a high failure item?

I can't find anyone at all that will change it out.

If overtightened you can destroy the rear end.

I recently pulled the drive shaft in my GL1500 Lehman trike in order to replace the pinion seal. There is now a slight vibration, which was not present before the repair, which can be felt during acceleration but not deceleration. It is also present under constant throttle at speeds above 65-70 mph. This is a very subtle vibration, almost like a "buzzing" and is felt more through the handlebars than the floorboards. It is not the same as was felt when the front u-joint in my Valkyrie trike went bad. That was much more pronounced and was felt almost completely through the pegs and only went away at constant throttle.

The front u-joint had no slop/play in it but was very easy to move. Almost no resistance. I am 99 % sure that all the "rollers" in the rear u-joint were correctly placed and undamaged. I indexed the drive shaft upon installation. I hate to start throwing parts at this, especially at the cost of a front u-joint these days. So my question is does anyone have any suggestions as to what this could be? And any tips for diagnosing would also be appreciated. TIA, Stan

Oh, BTW I did manage to destroy the front u-joint boot & did not replace it as I didn't have time to wait for a new one to ship. Don't see how that could be relevant, but you never know.