Another vibration thread.

I have a 96 ext cab 4wd and after installing OME lift and AAL I have an annoying vibration. The lift has been on th e truck for a little bit. But not driven much. It has been in the paint shop and I had to replace the heater core and some other things. I have shimmed the center bearing and got the vibe better but I want to do a real fix on this. The vibration was not there prior to lift. I am thinking take out the aal, remove the cb shims and check angles of the driveline to take it back stock that I can compare to the angles with the AAL installed and then order steel angled shims for the pinion angle. What are some of your thoughts on this approach? I did explore doing a one piece drive shaft and went to a well known and established driveline shop and they advised that a one piece drive shaft wouldn’t be a good idea for the weight put on the output of the trans. I know there are several out there running them but this is what they told me when I mentioned it will be a daily driver. Thanks in advance.

 

Anyone?

 

What is AAL? What center bearing are talking about that you shimmed? The driveshaft carrier bearing? I guess you're talking about shimming under the rear leaf springs to rotate the rear axle and get the pinion angle better?

It sounds like you're assuming it's a driveshaft issue when it could be a problem with your front differential. I think it's very possible the vibration is due to the driver side needle bearing that the CV shaft rides on. Check out the video.

https://www.youtube.com/embed/sXIfHArtvF8

 

Thanks for the input. I will try and clear some things up. By AAL I mean Add A Leaf. Center bearing is the center support bearing or carrier bearing on the rear two piece drive shaft. I did the front diff drop when I lifted the truck and I am not saying that it’s not the front drivers needle bearing but when I shimmed the carrier bearing, the vibrations almost all went away. My thoughts above in my original post are that I need to do some kind of angle shim under the rear axle to correct the pinion angle? Any input on that?

 

I only have a little experience with putting lifts on a Tacoma, but when I put a 3" lift on one, there was no need to do any of the things you're addressing. But, I'm wondering, do all Tacomas have a rear driveshaft that uses a carrier bearing or is it only for the long bed models? What you're addressing makes total sense now. The carrier bearing shims you installed went in between the frame and bearing support bringing it closer to the ground reducing the angle of the driveshaft and taking pressure of the u-joints.

It is fairly common that after a lift, u-joints can't handle the new angle because they were worn and on their way out already. It's kind of like when CV boots rip because the new angle of the CV shafts is too much for the boots to take and they rip. I suspect one of your u-joints is probably in rough shape and it's causing the vibration you're experiencing. Unless shimming the rear axle like you're talking about doing is common practice with these rigs, I'd say your fix might just be finding which u-joint is the offending joint and replacing it.

I'm guessing you've greased all your u-joint zerk fittings and the slip yoke? Just remember with the double cardan joint, there are 3 zerk fittings, one for each u-joint and one for the center ball.

 

When I carried my Shaft to the driveline shop they checked all of the joints while I was there checking on having a one piece made and they had no slack or any issues. I grease them pretty much each time I change oil. That’s what leads me to believe that the pinion angle is the culprit. FYI my tacoma is an extended cab regular bed. I can’t speak for the other first gens but I believe that any of the extended cabs or the double cabs all have carrier bearings.

With all that being said, how does my approach to getting back the stock angle in my original post sound? Maybe? Lol

thanks for your input @Timmah!

 

I'm thinking your lift changed the pinion angle. I have same issue chasing out (next on list) after we did a leaf replacement with General HDs. The height change was more than expected and the vibration was new. Get a digital angle level from HD and place on output flange and pinion flange. Google the internet on pinion angle and most all say these should be parallel to prevent the ujoints from rotating at different speeds or oscillating. I'm going to add a wedge shim when I get back which should take care of the issue. Spicer had a really good video that showed oscillation and difference in speed from bad pinion angles.

 

when does it vibrate? At idle at 30mph?

 

I had to shim my axle 3 degrees with only a 2" lift. Had an annoying vibe around 45 mph, new carrier bearing didnt fix it and dropping it only changes the angle at the front of the driveshaft. Some people get post lift vibes and some dont, nothing you can really do except install shims while youre installing an add a leaf.

 

Best bet is to always shim a Taco axle while lifting it. Beats having to tear it back apart.

 

I am wondering if you could take the rear half of the rear driveshaft off put her in 4 wheel drive and take her for a spin an see if the vibration diappears.

 

There were no vibrations prior to the lift. The vibrations are at take off and at highway speeds. Around 65mph. The vibration is still there with the carrier bearing shimmed but not as bad. I am just trying to figure out a way to know exactly the degree shim I need to only have to do this one time and get the carrier bearing and front half of the rear drive shaft back to the original operating angles.

 

1 degree for each inch of lift. But doing slightly more wont hurt. Most here do 3 degree, including myself.

 

Sweet! So with about 1.5” from the AAL that should be a 2* shim.

 

Id go with 3. Thats what I have with my 1.5" AAL.

 

And no vibrations throughout any speeds?

 

nope

 

Thanks for the input @Blue92 i was thinking 2.5 or 3 from the multitude of other posts I read on the subject. Seems like those are the most common with that amount of lift.

 

I am having nearly identical problems to the OP. The difference for me is that I put in a brand new two piece rear shaft after the original
got torn up on some rocks. I added the lift, then the new shaft, but vibes are persistent at 65-75 and at around 30-40. I believe the shim is the answer, but which direction does the skinny end point? If we are trying to make the pinion and transcase output more or less close to parallel, I'd think that the shim should go fat side forward...right??

 

1Fine40 I thought the same thing the first time I installed my shims wrong the first time with the lift but only made my problem worse. You have to keep reading, in a single u-Joint application you would make the pinion parallel to the T-case but these Tacomas have the double U-Joint at the intermediate which negates reference the T-Case. The T-case is parallel to the first u-joint just due to the OEM hard mount of the carrier bearing (meaning the first half is done.) The pinion needs to come up to become parallel with the rear u-joint at the carrier bearing. Easiest check is to simply put a socket on the cap then protractor on on socket to get angle reading (socket just used as parallel gauge from reference) - roll driveshaft till cap is at bottom center then measure angle.