High 3rd gear, low 4th gear vibration (2 Viewers)

[pb4ugo]

Ok so as far as I can see from the photos, your drive shaft looks out of sync - I'm not an expert so please anyone else weigh in here!
This could be the whole problem, or just a part of it.

See photos below.
Firstly, I've circled the grease nipples. Buy a grease gun and lithium grease. You'll also need moly grease for the steering joints - look at the front of your rig - anything that moves has a nipple on it.
Pump clean grease in until it comes out of the joint.

Secondly the green lines should be oriented the same (if the prop shaft is sync'd).
You'll see that your front joint is vertical, while the back joint is at 45 degrees. (I assume that you didn't move the truck in between photos).

You'll need to remove the 4 front bolts, pull the shaft backwards off the handbrake, and then slip the front half of the shaft forwards until it separates from the rear half.
You then need to turn it until both ends are aligned. Turn the hand brake drum to match, and reassemble.

Then pump the slip joint and universal joint with grease.

View attachment 3417946

View attachment 3417948

Good catch. The only thing I would suggest is it probably easier to remove the d/s end from the pinion end, sometimes its difficult to compress the d/s. There's no studs to contend with. You need to align the yokes. This is most likely your issue.

 

[peesalot]

First off, are the hubs unlocked & the tcase in 2wd ? The rear driveshaft is out of phase. You see in the pic the tcase end of the driveshaft is 12 & 6 ( straight up & dowm more or less) the axle end is clocked what looks like 2 teeth to me, remove shaft, pull slip spline apart, rotate so the ears of slip yoke & the ears of the long tube are in the same plane, slide spli yoke back in, reinstall driveshaft, put axle end on, put tcase in nuetral and spin ebrake yoke to line up. Thats probably the majority of the issue and the other issue that causes this is worn slip spline and you'll have a chance to check those out as you reset the phasing to proper.

 

[45Dougal]

Fair enough. I've never removed the back end. My front joint came off easily enough, but maybe it's harder with your short trucks

Tbf its hard to tell the alignment in the photos - I'd go check it in the flesh, but they should definitely be aligned, and if they're not then you get bad vibration.
And yes it's an easy job to fix but you do need a fairly narrow socket to get to the nuts (14mm socket - a 3/8" drive should do it, but 1/2" drive are too chunky) and you'll probably get a bit dirty from the old grease.

 

[truckfighter]

Fair enough. I've never removed the back end. My front joint came off easily enough, but maybe it's harder with your short trucks

Tbf its hard to tell the alignment in the photos - I'd go check it in the flesh, but they should definitely be aligned, and if they're not then you get bad vibration.
And yes it's an easy job to fix but you do need a fairly narrow socket to get to the nuts and you'll probably get a bit dirty from the old grease.

You guys are awesome, thank you so much for the help.

I don't mind getting dirty at all, and any excuse to buy more tools is ok with me!

 

[peesalot]

if you search out of phase driveshaft or phasing you will find pics & descriptions on here for clarity. FWIW with hubs unlocked and tcase in 2wd you should be able to spin front shaft easily by hand.

 

[45Dougal]

First off, are the hubs unlocked & the tcase in 2wd ? The rear driveshaft is out of phase. You see in the pic the tcase end of the driveshaft is 12 & 6 ( straight up & dowm more or less) the axle end is clocked what looks like 2 teeth to me, remove shaft, pull slip spline apart, rotate so the ears of slip yoke & the ears of the long tube are in the same plane, slide spli yoke back in, reinstall driveshaft, put axle end on, put tcase in nuetral and spin ebrake yoke to line up. Thats probably the majority of the issue and the other issue that causes this is worn slip spline and you'll have a chance to check those out as you reset the phasing to proper.

Yea greasing the slip splines will probably help dampen out whatever wear you have there too. Hope that fixes it all!

 

[Casey E]

Ok so as far as I can see from the photos, your drive shaft looks out of sync - I'm not an expert so please anyone else weigh in here!
This could be the whole problem, or just a part of it.

See photos below.
Firstly, I've circled the grease nipples. Buy a grease gun and lithium grease. You'll also need moly grease for the steering joints - look at the front of your rig - anything that moves has a nipple on it.
Pump clean grease in until it comes out of the joint.

Secondly the green lines should be oriented the same (if the prop shaft is sync'd).
You'll see that your front joint is vertical, while the back joint is at 45 degrees. (I assume that you didn't move the truck in between photos).

You'll need to remove the 4 front bolts, pull the shaft backwards off the handbrake, and then slip the front half of the shaft forwards until it separates from the rear half.
You then need to turn it until both ends are aligned. Turn the hand brake drum to match, and reassemble.

Then pump the slip joint and universal joint with grease.

View attachment 3417946

View attachment 3417948

The first pic is rear shaft and the second is a photo of front drive shaft. FYI

So the pics don’t tell if it’s in sync or not.

 

[Casey E]

Looks fine to me. I believe everyone is looking at the wrong pics.

 

[Casey E]

First off, are the hubs unlocked & the tcase in 2wd ? The rear driveshaft is out of phase. You see in the pic the tcase end of the driveshaft is 12 & 6 ( straight up & dowm more or less) the axle end is clocked what looks like 2 teeth to me, remove shaft, pull slip spline apart, rotate so the ears of slip yoke & the ears of the long tube are in the same plane, slide spli yoke back in, reinstall driveshaft, put axle end on, put tcase in nuetral and spin ebrake yoke to line up. Thats probably the majority of the issue and the other issue that causes this is worn slip spline and you'll have a chance to check those out as you reset the phasing to proper.

I’m about 90% sure you’re looking at two different drive shafts. His pictures are out of order.

 

[45Dougal]

I’m about 90% sure you’re looking at two different drive shafts. His pictures are out of order.

The exhaust is at the back of the truck, right?
Maybe you're right. The angle is hard to tell for me at least.
Yea I posted the wrong pic

 

[Casey E]

The exhaust is at the back of the truck, right?
Maybe you're right. The angle is hard to tell for me at least.
Yea I posted the wrong pic

View attachment 3418028

Yes it’s at the back. Hopefully the poor fella hasn’t already removed the shaft to find out folks are looking at the wrong pics. Lol

 

[peesalot]

I dont care what order the pics are in I am familiar enough with cruisers to know what I am looking at.

 

[Casey E]

I dont care what order the pics are in I am familiar enough with cruisers to know what I am looking at.

Can you show where it’s out of phase ? Looks fine to me. You are describing two different pictures in your stamens above. The driveshaft is phased correctly in the pics.

 

[45Dougal]

Still looks off to me, but hard to tell from this angle despite the flowery language

Any other suggestions for a cause?

 

[Casey E]

Still looks off to me, but hard to tell from this angle despite the flowery language

Any other suggestions for a cause?

I’d grease it and take it for a spin first thing. Then if that doesn’t work he should remove the shaft and check the phase on the ground and at the same time check the transfer case and rear axle angles. My eye says it has a small lift so he might need a shim in back. While it’s off you can feel for the spline wear, def could be bad joints and spline wear from lack of grease.

I doubt this is it but he should also check to make sure he’s running the correct bolts in the drive shaft, I’ve seen someone accidentally running the smaller early bolts, the shaft will bolt up but you won’t get it perfectly square since the shank is smaller.

 

[45Dougal]

Greasing it is quick, easy, and cheap, so gets a vote from me.

 

[truckfighter]

if you search out of phase driveshaft or phasing you will find pics & descriptions on here for clarity. FWIW with hubs unlocked and tcase in 2wd you should be able to spin front shaft easily by hand.

I’d grease it and take it for a spin first thing. Then if that doesn’t work he should remove the shaft and check the phase on the ground and at the same time check the transfer case and rear axle angles. My eye says it has a small lift so he might need a shim in back. While it’s off you can feel for the spline wear, def could be bad joints and spline wear from lack of grease.

I doubt this is it but he should also check to make sure he’s running the correct bolts in the drive shaft, I’ve seen someone accidentally running the smaller early bolts, the shaft will bolt up but you won’t get it perfectly square since the shank is smaller.

Definitely has a lift, I think I calculated it's close to 2" but you're talking to an amateur so I'm not positive...

 

[45Dougal]

Any luck determining if the prop shaft was correctly aligned?
I remember noticing that my hand brake drum was heavily drilled around the rim (factory I assume) to balance it.
Possible that a worn drum might cause some vibration too I guess.
You could try applying a bit of drag on the handbrake to see if it stops the vibration.

 

[truckfighter]

Any luck determining if the prop shaft was correctly aligned?
I remember noticing that my hand brake drum was heavily drilled around the rim (factory I assume) to balance it.
Possible that a worn drum might cause some vibration too I guess.
You could try applying a bit of drag on the handbrake to see if it stops the vibration.

I'm trying to educate myself on what everyone has suggested here - there's a lot of terminology that is WAY over my head at the moment and some of the things suggested seem pretty daunting. But I did have a friend stop by Saturday and according to him, the drive shaft is correctly phased. I'm trying to comb the forums and google to see how I can check and verify that myself before I go wrenching on the flux capacitor and get brakelight fluid everywhere. I DID get the grease gun out and hit all the zerk fittings I could get to along the driveshaft - seems like the one inside the u-joint at the very front and the one in the very back are in such a tight spot I can't get my gun on those, so I either need a different fitting on my gun or figure something else out. I'll take it for a spin later and try the handbrake trick!

 

[charliemeyer007]

They sell attachments for grease gun tips to get into tight places - most of the time it getting the zirk in exactly the place so the regular tip will go on. For the rear shaft, jack up a wheel(s) to spin the shaft or just push the truck.