Drive Shaft Vibrations Solved Step-by-Step

I think when you go skinny side forward, you're actually angling it up. Because the fat side of the shim in the rear pushes the rear of the axle down, thus turning it counter clockwise and up (if looking from the side). Anyone correct me if I'm wrong. The funny thing is, in the updated OP's first post, he says to just face the shims forward. But later in the thread talks about installing them backwards.

 

I'm tempted to play with my shims and take angles with each orientation to see how it changes the driveline. I might test my spacer theory for the cb and shove a half inch of washers in there. If it drove vibration free before lifting it another inch, it would make sense to drop the cb close to that distance so it's back at the angle it previously was

 

Skinny side forward tilts your rear further up, not down. That's assuming your 2nd gen is the same as my 3rd gen, with your spring perch and leaf pack on top of your axle.

I feel like I'm following you around jewels....it seems to me there are 2 train of thoughts in work here. The first is to point the rear pinion towards the carrier, the other is to make sure that the rear pinion is equal to (or actually a bit pointed down) relative to your transfer flange. After measuring my truck and finding that the rear pinion is 3.4 degrees 'up' relative to the transfer flange, I'm going to do the latter, which is going to cause me to remove the factory shim (the one you already removed when you went dakar) and add a 3 degree shim fat side forward. After doing the math on it, I think that will put my rear pinion right at .7 degrees 'down' relative to my transfer flange. Then I'll play with aligning the two drive shafts after that.

Does that make sense? Did you get your inclinometer yet?

 

Yea makes sense, I'll have to take a pic, I swear it looks like it's doing the opposite but it could just be how I'm looking at it. I measured it a few days ago and I'm pretty sure the opinion is angled up about 0.7-1 degree

 

Yes logic makes sense. However what doesn’t make ANY sense is why on your lifted truck you’d have to install shims fat side forward which is the complete opposite of what most people do to get rid of vibes. Somethings not right and I would advise you to talk to an expert. All the companies including Toytec and HeadStrong says skinny side forward. I’m on a third gen. If you think about it... when you lift, you’re raising the angle so to match that higher angle you angle upwards, lessening the angle. Makes sense to me but I’m no expert.

 

Maybe its just my leaf pack that looks angled as hell, my pinion is definitely pointing up, perhaps even more than it should be

 

It looks pretty normal. I wish more experts chimes in on this thread as we’re both guessing with everything

 

This thread is confusing with a couple of different ways of tackling the issue, but I'm not sure why you're guessing or needing more expert advice. Both ways are laid out pretty well in the thread.

I chose to follow the pdf provided, you can view it on post 736. It's step by step instructions, very well laid out. It says you want your rear pinion "a few tenths" down from your transfer flange. Zero on the transfer flange, measure your rear pinion, there's your shim. This method will cause me to put the shim fat side forwards to bring down my rear pinion, and then adjust the CB. If this method doesn't work I'll try the other, it doesn't take long to spin the shim around.

I get that most are putting shims the other way, but that's just another way of doing it. Pick one and run with it.

I trust the knowledge of the dozens of people that tested/tried methods in this thread alone to the advice of someone selling me parts, but that's just me. I also don't have any parts to buy either so asking them would be just wasting their time.

Doing it this weekend, I'll post back how it goes. Based on this thread, it won't be correct on the first try.

 

Based on that PDF mine needs to come down as well, but who is the person stating it needs to come down? And why should we take one method over the other? Makes me wish I had taken measurements at stock ride height to see if the pinion points down when it's OEM.

 

Check out post #34, maybe that will answer some of your questions. I went with option 1.

 

That definitely seems the best so you don't have extra wear and tear. I actually have my angle finder and ruler in the truck, maybe I'll crawl under and measure real quick. Pretty sure when I zeroed on the transfer my rear pinion was 3.7 degrees off. If zeroed on the rear shaft, the pinion was only 0.7 degrees difference. I have 2 or 2.5 degree shims in right now, can't remember, so in that scenario rotating them around would actually bring it back to parallel.

 

UPDATE: Took it in to the 2 ASE cert master techs that originally installed the lift. They have a lot of experience with lifted trucks, and have done a few tacomas recently. They took it out, test drove it and said they didn't think it was driveline related. I remember reading on here that a way to test if its actual driveline vibes is to take the driveshaft out, then go ride around in 4Hi (essentially making it FWD). Well, they did just that and guess what? Still the same exact vibes. After inspecting everything, re-torquing and greasing... they concluded it was most likely my aggressive duratrac tires. I have had some balance issues with them recently, and in the back of my head I was wondering if it is the tires.

So, not sure if it was said in this thread or not already... but instead of messing around here and there with shims/angle finders and cb drops... take the whole damn drive shaft out and drive around in 4Hi. If the vibes are still there, you know its not the pinion angles.

I'm just gonna live with the very minor vibe I have. They looked at everything it could possibly be and I trust their judgement.

 

If is the vibration coming from the front end, it would be the needle bearing on the left side of the differential. Most vibrations after a Tacoma lift come from your pinion angles are off on the rear differential. The only way to tell is to put a factory style street tire on to see if it’s the Duratracs or not. Most people left the truck and put tires on at the same time, so you don’t know which one caused the issue then you chase yourself in circles trying to find it .

 

Thanks. I had the ECGS bushing installed. They pulled the driveshaft and drove it verifying the noise was still there... so they think it’s the tires. I’m already over it as it’s so slight

 

I put that shim on there fat side forwards and my rear pinion ended up 3 degrees down from the transfer flange, don't get that as the math doesn't work but whatever. Vibrated like an SOB. Turned them around and ended up 4.3 degrees up on the rear pinion relative to the transfer flange, all is good now. Final measurements... 0'd on transfer flange, 3.6 on first driveshaft, 4.2 on second driveshaft, 0'd on second driveshaft, .1 degrees on rear pinion.

Just as I was finishing up, my archive hangers arrived....so now I have to tear it all apart again!

This thread was awesome, thanks for it.

 

you are .6 degree difference .... .5 is what you try to get ...thats is why you should be vibe free

 

I’m assuming most people know it’s a driveline related vibe by the time they are shimming and all? Because the first troubleshooting thing should be to remove the drive shaft, drive around in 4Hi and if the vibe is still there it’s not your driveline.

 

1. Vibe can come from front, or back of driveline, (ex. Pinion angle wrong, or front needle bearing )

or

2. Tires

The trouble most people have is they lift and put all terrain or mud tires on at same time. - the easiest way to avoid some of these hassles is to, lift and align first, then test drive. If no vibes, then install tires. This will go along way in determine where any vibe would come from. If you are going with tire that could fit on truck before lifting, then you can put tires on 1st.

If you not sure where the vibes are coming from, then you are chasing your tail.

 

For me at least, my truck was already lifted and on all terrains so when I lifted it more I knew the issue was solely because I changed the angles more.

 

Did you have to do any CB shimming?