OME Light/Medium 2.5" Lift and driveline vibrations (1 Viewer)

[Mark Jennings]

I don’t know, maybe rear shaft in the picture then.

And this have to be 60-series:
View attachment 2534554

In newer Cruisers it’s in other way:View attachment 2534553

So, no matter.

Newer cruisers????? Under side of 2020 LC, both slip joints at T-Case, can’t get much newer....go figure? Kind of a head scratcher, eh??? (Lol)

 

[Crush 4]

I started with 2* and it reduced vibrations, but its still there at 30mph and over 50mph.
So went to 4* which caused the noise in front end described in post 1 but all the vibrations went away.
Went back to 2* and that noise is now gone....but back to vibrations from 28-34mph and over 50mph.

I thought you put shins in rear fat part facing forward, with a lift and extended shackles? No?

 

[AutaviaFJ40]

I thought you put shins in rear fat part facing forward, with a lift and extended shackles? No?

2* shim is in rear currently, but it is facing rear. I posted a photo in post #34
Springs are OME light/medium
rear shackles seen in post #21

 

[AutaviaFJ40]

I took the truck to a shop the specializes in drive shafts and alignment. They balanced the drive shaft, which helped...but vibrations persist. He then put the truck on a lift and tried to mimic the vibration at 50mph when he noticed that the vibration was occurring at the rear of the transfer case. any suggestions?
fluids ck
ujoints ck
no free play ck
driveshaft balanced ck

 

[Crush 4]

I took the truck to a shop the specializes in drive shafts and alignment. They balanced the drive shaft, which helped...but vibrations persist. He then put the truck on a lift and tried to mimic the vibration at 50mph when he noticed that the vibration was occurring at the rear of the transfer case. any suggestions?
fluids ck
ujoints ck
no free play ck
driveshaft balanced ck

I am far from an expert and may have missed this in your thread but here is my 2cents
If the shims are facing toward the back it would rotate the axle down, as such the pinion angle may be at the wrong angle to the TC. Again I may be way off but my understanding is shims face forward, rotating axle/ pinion upward. With your lift and shackles it would be 4 degrees.
If you do the search thing you May see more on shims

 

[AutaviaFJ40]

Thanks for the response.
I tried 2* shims both directions with no change. 4 degree shims caused a secondary issue described in my first post.
Multiple people have told me that OME 2.5" lift doesnt require any shims in the rear though.

but when the truck is on a lift, wouldn't it negate any effect the shim would offer? I still have a vibration with truck on lift.

 

[Mark Jennings]

Balance the e-brake drum or is it new enough that it has rear wheel parking brake....also maybe a bent drive shaft or the spline in the slide are warm and loose.

 

[AutaviaFJ40]

its an 81 with rear drum parking brake...drive shaft checked out throughly and balanced. vibration seems to be in the rear output of transfer case

 

[Crush 4]

its an 81 with rear drum parking brake...drive shaft checked out throughly and balanced. vibration seems to be in the rear output of transfer case

I know this stuff is frustrating and can drive us crazy!
I read this thread may be helpful if you haven’t seen it

Expert Advice Needed for Drive Line Angle Shims

Hey all, My rear drive line angle has been bad ever since I installed the new OME Medium Duty suspension, 2.5 inch lift, and I've been getting some vibration coming from the rear end. I had some time today so I checked the angles with all four wheels firmly on level ground, the results were...

forum.ih8mud.com

 

[DangerNoodle]

Is there any play if you try and wiggle the output shaft or push it up and down?

 

[AutaviaFJ40]

Is there any play if you try and wiggle the output shaft or push it up and down?

no, zero play. Could it be too tight?

 

[DangerNoodle]

no, zero play. Could it be too tight?

I doubt it. I was more wondering if there were any signs of bearing failure or bad tolerances in the tcase.

 

[AutaviaFJ40]

I doubt it. I was more wondering if there were any signs of bearing failure or bad tolerances in the tcase.

im going to check it again, thanks

 

[-MaTTi-]

I can see your bypass-hose. So the TC might have been too dry at some point before. I would check the output flange bearings too.

 

[AutaviaFJ40]

I did check levels again yesterday, and they were good on both sides...when we replaced the clutch we dropped the trans and replaced the seal. I left the hose in place just in case. Everything looked great, but will defiantly ck again.

 

[Blue77FJ40]

You don't/shouldn't need shims in the rear. The shim goes in the front axle and since you have stock sprung under configuration, the fat part of the wedge faces the front. This will get rid of any squirrely steering you may have experienced. Vibrations I have experienced after a lift were due to out of phase driveshafts. You may also want to check the ujoints themselves, if they are in good condition and properly lubed.

 

[AutaviaFJ40]

You don't/shouldn't need shims in the rear. The shim goes in the front axle and since you have stock sprung under configuration, the fat part of the wedge faces the front. This will get rid of any squirrely steering you may have experienced. Vibrations I have experienced after a lift were due to out of phase driveshafts. You may also want to check the ujoints themselves, if they are in good condition and properly lubed.

I have heard this from multiple sources, I currently have a 2* shim in rear which I planned on removing. Ive tried it both directions and dont notice any improvement. Whats odd is that when I went to 4* shim vibrations were gone completely, but I had the grinding sound from what sounded like the TC. Removed 4* and that sound is gone, but vibration back.

I tried 2* in front and didn't notice any improvement, so removed. My steering is fine...but I will go back to this once I can properly measure the caster angle on front. First priority is to solve this vibration. Driveshaft has been gone thru twice. Its in phase and balanced, new u-joints installed and properly lubed. This was just checked and balanced by a shop that specializes in driveshafts.

The PO had installed a shackle reversal, which I had removed when adding the OME Springs...I bought a set of Toyota spring perches and had a local shop replace the homemade perches. If the location of the new spring perches were installed slightly forward or back from spec, could this have any effect? I have a frame chart in the fsm, so ill check it out this weekend.

 

[AutaviaFJ40]

just did a quick check and all looks correct on location of spring mounts.

 

[Blue77FJ40]

Not sure what to tell you. I can only give you my experience. My '40 was bone stock, untouched. I initially added the OME 2.5" lift and installed steel 4 degree shims in the front. That fixed the squirrely steering I was having. I didn't have any vibration. I went to 4" HFS and used the same shims.

I did however have vibration on my '85 mini that I installed OME suspension kit on. I found the rear driveshaft was out of phase a small amount, fixed that, and that took care of the vibration. It never vibrated until the lift.

 

[-MaTTi-]

Whats odd is that when I went to 4° shim vibrations were gone completely, but I had the grinding sound from what sounded like the TC. Removed 4° and that sound is gone, but vibration back.

You should figure out that grinding sound. There should be any if everything is good.