Correct Axle shim direction

I'm just going to say this. Fixing this issue is a BITCH. I think some trucks are worse than others and mine is a finicky one. There's only so much you can do with the stock driveshaft configuration, and for some, they get it. Others go through tons of combinations, trying to account for wrap and don't get quite lucky enough.

 

Yeah, makes sense....I didn’t mean to use both though, I was saying it’s better to use leaf springs instead of blocks to reduce wrap.....
Is there a maximum amount of lift on the 3rd Gen’s you can go before needing to change the pinion angle or is it recommended to shim for any height suspension lift?

 

It seems most kits for 2"+ of lift include shims or carrier bearing spacers. 2" blocks and higher are usually tapered, like a built in shim.

That said I just threw in 1" blocks and I'm having the slightest of vibrations around 20mph (which to be completely honest may have been there before, I just never paid attention to it). I'm playing around with dropping the carrier bearing to correct for the small change in driveline angles, but it doesn't seem to be helping yet...

 

Ignorance does not equate to luck or lack of.

Thousands of posts across many forums all crying the blues because they can’t figure out their vibrations / oscillations. Finicky ones means exactly what? You can’t figure it out so it must be finicky. I bet when your doctor can’t figure out your illness in 5 seconds or less your malady must be finicky.

In each and every situation the solution is based in math. Angles, oscillations, forces being cancelled by equal and opposite forces. Tacoma’s are plagued by something so simple that makes each and every change handcuffed right from the start. Tacoma’s are SOA (spring over axle) which is unlike MOST other leaf spring vehicles and for a reason. A SOA vehicle has a longer lever acting on the leaf spring which puts more force into the springs vs a SUA (spring under axle) setup. Adding a block further exacerbates the situation with a SOA.

Tacoma’s start with SOA with it’s inherent spring wrap handicap. Add larger tires which increase the forces required to turn them and the opposite forces required to keep the axle from wrapping. Add a block into the mix and the issue keeps putting more and more force into the leaf spring. All of this is why I talk about ignorance. Ignorance of these forces and their effects on axle wrap and oscillations does not mean that you have a finicky truck. It means you don’t understand what is going on so you are chasing your tail. You throw parts at the problem and when you don’t get instant results you want to throw more parts at the problem. You must understand what is going on first. Only then will you know if you are winning or losing after each attempt to remedy the problem.

I previously owned a Jeep with a SOA lift which had massive issues with axle wrap and vibrations. The solution was a Tom Woods double cardan shaft with a slip yoke eliminator kit (ignore if you don’t know Jeep transfer cases) and heavier leaf springs designed specifically for a SOA Jeep. The DS was longer thanks to the SYE which helped with angles and the double cardan DS helped further with angles. The heavier springs helped eliminate axle wrap. Now all is good and vibes are gone. A couple months later the issue is back. Go back and check my angles (always check and recheck and then repeat) and I realize that as the new springs broke in and settled slightly my pinion angle was now off slightly resulting in the new vibes. My option was cut off and reweld the spring perches or use an angle shim. I used a small angle shim and got my angles back to where I wanted them. Never had an issue again. Now we are talking a DS that is insanely short compared to a Tacoma. So why is it that such a short driveshaft can be made to be vibration free yet a longer one in a Tacoma is such an issue? Lack of understanding of what is actually going on. Simple as that. This isn’t a situation where one person posts for help and everyone else just buys part# 123456 from XYZ company. Read through all of the posts on TW for vibration issues and that is the expectation. No one is willing to do the real work in identifying their exact issue they just want someone to post part numbers. That is why some are successful and others feel their truck is finicky. Now to add to the story my vibrations / oscillations were so bad on that Jeep that I would literally melt the u-joints out of the DS in under a couple thousand km. That was reduced to under 100km if I travelled the highway. So think about that for a second when you claim your issue is unsolvable. And I do mean I melted the crosses off of a u-joint to the point the DS came apart and looked like the cross was torched off.

 

I refuse to answer this as a general lift amount.

The answer is in the measurements. A stock truck with weak springs could have the same issues as a heavily modified truck with every part thrown at it. It all depends on the angles and the spring wrap. Two trucks side by side on the lot brand new could behave differently regarding driveline vibrations. Same parts right? Same truck right? Same mileage (or lack of). So what is different? Check the angles. Every single solution starts with checking the angles and identifying what goes on (angles) when accelerating or decelerating. Have I said angles enough yet?

 

Couldn't have said it better myself

 

I know I can come off pretty harsh when discussing driveline vibrations. Been explaining it on different forums for ages. Same story, different vehicle bla, bla, bla....... It always is solved by math / measurements. Problem is caused by issues with angles and is solved by understanding and rectifying the issues with those angles.

I have even mounted a backup camera under a vehicle to see what was happening as I drove to better analyze a vibration problem once. That was a bent axle housing but it was identified by eliminating all other common sources of vibration.

 

I've been under my truck over 70 times screwing with this since doing a very modest 1.5" lift. Changed leaf springs, measured angles, shimmed, measured, shimmed. Rinse and repeat. Ultimately I had to replace the driveshaft with a custom double cardan unit to resolve the problems. I tried every variation of shims in both directions, carrier bearing drop, carrier bearing flip and pretty much everything in between with the stock driveshaft. It would never clear up to my satisfaction. I'm OCD about stuff like this, so what bugs me may not bother most people. All I was saying is getting it right is a bitch. Measuring once and nailing it straight away doesn't seem to be most folks experience. Some get lucky with a CB drop, others suffer. Hell, even the 3rd Gens are vibrating stock, like the 2nd Gens did as well.

 

The article you're referencing is:
http://www.4xshaft.com/JR7_TW_Driveshaft.pdf

But I think the Spicer document has more relevant information for our two-piece driveline system (page 5, 13, 14):

https://www.waterousco.com/media/wysiwyg/pdfs/content/J3311-1-DSSP.pdf

It sounds to me like OP is making a good effort to understand what needs to happen.

 

No one has ever said measure once and you will get it first time. Problem is people don’t understand what is going on so they chase their tails. Add 1000lbs of load to the bed and it changes the DS angles. Pull a trailer and the added load may contribute to axle wrap. Larger tires may create axle wrap.

Measuring the angles while stopped only gives part of the information. What will the axle do under load from acceleration or stopping? What additional load did you introduce by adding larger tires?

YOU DONT TAKE MEDICATION UNTIL YOU UNDERSTAND YOUR AILMENTS. So why do we start throwing parts at something until we understand what is going on?

 

I know what's going on because I fixed my problem, but you seem to be really passionate about this topic. As you've pointed out, the variables make solving it more difficult. What works for one person, may not work for another. Two trucks with the same exact configuration, may behave differently due to manufacturing variances. I never said throw parts at it, I just said it's a bitch to get right on these trucks.

I'm going to move along, so that perhaps you won't need blood pressure medication. lol

 

More attempts at trying to overcomplicate a simple situation. Two angles or 37 the same procedure applies. As one joint moves out of square it applies forces that oscillate and vibrate as the speed increases. Usually you have an equal angle / joint to offset and cancel out these oscillations. When they are unequal they don’t cancel out and you feel the vibrations. In a double shaft with a center carrier bearing the EXACT same procedure of making the joint angles equal and the oscillations cancelling out is the same.

In every single instance that there is a vibration there is an imbalance of forces (and sometimes just a huge swing from one extreme to the other “amplitude” which becomes harder and harder to equalize). Every single time. Could be a dented and bent DS. Could be a u-joint that is starting to sieze in one direction more than the other. Could be inequal angles. But there is always an imbalance in forces.

This is exactly why I usually avoid this topic. Manufacturing variances? Call it what it is. It is unequal forces which usually are from inequal angles. We muddy the waters by making shit overcomplicated and not calling things what they really are. Joke about blood pressure medication. Maybe I will pass next time a driveline thread comes up. Let the experts stub their dicks all day long and empty their wallets.

I am trying to beat it into people heads that the cause and solution are simple. Small vibes or large ones the situation is the same. People get all caught up in part numbers. Do I buy shims? Do I drop the carrier bearing? TC drop? Each of these “solutions” are doing the same thing which is matching angles.

When you keep the process simple the solution becomes just as easy. This is where everyone screws it up. People overthink this shit. They think they have a special or finicky problem. Just because it took a lot of effort to fix a problem doesn’t mean the problem was complicated. Make it simple and stick to it. Don’t overthink it because then you become the problem.

How many times does one say angles only to have others add their complexities that simply don’t need to be part of the discussion? If you want complicated then make it complicated and figure it out yourself. I have swapped axles, done lifts, cut and rewelded spring perches, torn apart and rebuilt transfers cases to shorten their overall length, cut and rewelded stock driveshafts and measured and spec’d out custom length driveshafts. Each time I either had no vibes or quickly identified and addressed the oscillations. This shit isn’t complicated because I keep it simple. If time and time again this is complicated for you either you aren’t as smart as you think you are or you aren’t keeping stuff simple.

 

LOL

 

Hay so I'm familiar with doing the math and figuring out what degree shim I need , so with that being said . My math showed me that I need a 1° shim. Now having difficulties finding that specific 1° shim curious if I would be ok with 2° shim . I have no vibrations till I get to about 65 to 70mph . I did upgrade to a tw double cardan read driveshaft eliminating the carrier bearing. Let me know what you think.