22 389 w low air suspension. 285” wb
With about 20-25 k on drives I’m measuring trans -1, front -1, and rear -9 degrees. ride height 8.75”.
Empty I’m -1, -2, -10 with 9.25” ride height.
Decal on frame says unladen rh should be 8.75.
Im noticing a slight roar/vibration under power that goes away if I slap it in nuetral.
Just fyi This is truck originally had a Cummins and now has a cat. Not sure if that would change trans angle any. I did measure angles off housings and not unjoints/shafts. Not sure if that would matter too much
22 389 Driveline angles/ ride height
Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by tnc110, Sep 24, 2022.
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Have you tried lowering the ride height to 8.75 unladen? Half an inch should not make much of a difference but its worth a try. The dealer should be able to tell you what the component angles and the drive line angles should be. The working angles of the U-joints should be the same on both ends of the drive shafts give or take half a degree. Swapping the engine could have changed the angle which could be corrected by shimming the front or rear engine mounts.
spsauerland and BoxCarKidd Thank this. -
Most all Paccar I have worked on is 2 or 4 degree engine angle vs frame angle. Last six of VIN and I can tell you factory angles.
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Did it have the vibration issue with the cummins also?
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If the vibration goes away in neutral I think we can rule out angles. Driveline spins the same regardless of in gear or neutral.
tnc110 and Diesel Dave Thank this. -
Glider? or your own creation?
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Did I read that correctly?
That is a 2022 truck with an older Caterpillar engine that does not have the correct emissions for that year truck?
That sounds more concerning than a little vibration.
As far as drive shaft angles and all that kind of thing whoever did the swap should have checked all of those angles and the angle that the engine sits in the frame before they pulled the old engine out.
Then you don't have to go back and scratch your head and not know where to begin or what happened or where to start from. That's as simple as just putting a little shim in if it's needed when you put the engine in it. Simple easy peasy instantly done no problem. I don't know that the newer mounts on the frame are in any different position than the older ones, but without any information that's just a question mark. Who did the swap? Unknown mystery mechanic?
Also I think the drive shaft angles themselves are supposed to be measured with the shaft and the joint not the housings. Your ride height has to be exactly wherever they tell you it needs to be.
With that being said make sure the ride height is correct and I would check your U-joints, carrier bearing, trans output shaft, pinion bearings, wheel bearings, and all suspension fasteners and I would check your tires. One time I had a vibration like that and it was the tire.
Good luck.Last edited: Sep 26, 2022
TheLoadOut Thanks this. -
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