Driveshaft & Pinion Angle Adjustment

So on my '03 extended cab, I upgraded to OME Dakar springs years ago as my OEM springs were flat and maybe going negative. when I put the put them on i was rocking a ARE mid height cap on the bed. about a month and half ago, I took the cap off and intended on leaving it that for the foreseeable future. ever since then I've had a decently annoying driveline vibration that I'm assuming is from losing that weight off the bed and therefore changing the pinion angle to one that has never been seen since the cap has been on before the springs. I'm thinking that its been bad for a while though because I had my driveshaft completely rebuilt & balanced by a dedicated driveshaft shop maybe 40k ago (definitely closer to 30k since I've only personally put 50K on the truck) and the carrier bearing bushing is already shot. I would say there's probably an inch of play in the bushing itself.
When this vibration is occurring, I can step on he accelerator and make it go away as I'm climbing speed regardless of what speed I'm at which leads me to believe one (or both) of the following two things, 1) the acceleration is causing enough axle wrap that is self adjusting the pinion angle and therefor temporarily fixing the issue, or 2) the carrier bearing has enough play in it that its finding its optimal position and effectively doing the same thing in self adjusting the pinion angle and fixing the problem temporarily.


Can anybody point me in the right direction of how to figure out which degree shims I should use if I were to go that route or would it be better to use a carrier baring drop kit, or both for that matter? where would you start? also, what are the acceptable parts for the carrier bearing and u joints? I have to believe the pinion angle is what has caused the driveshaft to go to shit this quickly considering the original lasted over 100k

 

If you are going to run that way you could remove a leaf or a couple from that Dakar pack. Do you have the HD ones? That might help. Or run around with sand bags in there for the time being.

 

i would rather just fix it right instead of toting around useless weight. Even with the cap, its obviously been taking a toll on the driveshaft since the carrier bearing is shot in well under 50k. probably closer to 30k

 

Put spacers in between the Carrier, bearing and frame. That will change the angle. Depends on how much of a lift but half inch to three-quarter inch spacers
Also, replace the carrier bearing if it is bad.

 

The only way to do it right is to check the angles. Harbor freight sells a cheap one for like $5 that works but you can find better digital ones out there. You need to measure multiple surfaces and find the delta of each which should tell you what degree you need at the pinion. It can be adjusted either with axle shims or washers under the CB...or both. I would do the axle shims first then the washer under the CB to fine tune. I believe ideally you want the delta to be 1 degree or less. Having said that, every truck is different and if you have a double cardan, in my experience it will be more forgiving to "extreme" angles.

 

you either need a 1, 2, or 3 degree shim. You can probably get a 2 degree shim and be fine. New u bolts. Thick end towards the rear of the truck. Don't go full torque on the new u bolts, maybe 1/2 way... take it for a short drive and see if it solves your issue.

 

I have a digital angle finder. I also have an analog one somewhere too, but I guess what I need to know is what the end goal is. I can take angles off everything in the drive train but then what do I do with that information? Is the ultimate goal for the pinion to be completely straight with the rear section of the driveshaft? Would that technically make the flange on the pinion exactly perpendicular to the drive shaft? I guess I should probably get the driveshaft repaired and everything tightened up for and then go from there? I just don't wanna be driving the truck too long after getting the driveshaft repaired nd end up with the same problem. When this vibration is occurring, I can step on he accelerator and make it go away as I'm climbing speed regardless of what speed I'm at which leads me to believe one (or both) of the following two things, 1) the acceleration is causing enough axle wrap that is self adjusting the pinion angle and therefor temporarily fixing the issue, or 2) the carrier bearing has enough play in it that its finding its optimal position and effectively doing the same thing in self adjusting the pinion angle and fixing the problem temporarily.

 

Before you go down this rabbit hole, here is a thread I started a while back: https://www.tacomaworld.com/threads/driveline-angles-sanity-check.764885/ It has a good diagram on how the measured angles should be calculated into operating angles. And another thread here: https://www.tacomaworld.com/threads/which-axle-shim-would-i-need-here.765576/#post-27323637

That thread references a calculator here: https://4xshaft.com/blogs/general-tech-info-articles/slopes-vs-angles

All that said- I strongly stand behind my previous post (#6 above). Just get some shims and go for it.

 

Yup, I totally understand the frustration because I had to go down this rabbit hole about a year ago and I wish my memory was better. I lifted my rear by 2.5" but it ended up closer to 2.75" because of the shim I added. So needless to say, that's quite a large lift that will cause problems for most people. I'm assuming that you have a double cardan because you have an extended cab. With a DC shaft, you want the pinion to point at the double cardan. So essentially it is perpendicular to the shaft. If it is not a DC, then the goal is to get the degree on each side of the shaft to match. I think the confusion is that most of the material that I was able to find was for the latter. You may want to check to make sure that your carrier bearing is still in good order and that the u-joints aren't shot which might be the problem to begin with. As another member mention, you can try and shim down the CB to see if it goes away since it's the easiest thing to do.


I forgot to mention. If you have a gopro, you can buy one of those magnet mounts and put it under the truck and go for a drive. That's what I did and you can see how bad your axle wrap is if you have it and how bad your carrier bearing is moving around and if it smooths out at speed.

 

Justin, did you ever get this resolved? I have the exact truck and setup and have piggybacked onto a similar thread for advice. My progression including detailed angle diagrams can be found here: https://www.tacomaworld.com/threads/driveshaft-angle-question.842913/

 

I used bushings like this and longer bolts between the carrier bearing and frame when I installed my ome springs.

 

@Parkvisitor do you happen to remember what size those are? Did you change your pinion anlge with shims at all? What was the result?

 

Stevo I used M10x1.25 70mm length bolts and the bushings from Ace Hardware. I have OME springs the extra leaf and probably a 2 1/2” rear lift. No driveline vibrations.

 

Thanks Juan, I made my own out of some 1/4" aluminum flat bar. Doubled up for a 1/2" drop. Maybe the 3 degree axle shims were overkill? Anyway, here is was my current angles look like:

 

Looks good, drive it, if no noise, it’s all good!!

 

That's the problem, I still have a shake over 65 and a noise that starts above 20 and just increases with speed. Sounds like a bad carrier bearing would sound but its a brand new 2-piece shaft from USA Standard gear that came pre-assembled with the CB in the middle. Everything should be in phase and balanced from the factory.

 

Pretty easy to inspect the C/B. If you replace I recommend the spicer.

The carrier bearing in your photo looks ok. I mean when they’re worn the D/S is noticeably dropped in the rubber donut.

 

It's a brand new carrier bearing that came with the pre-assembled two-piece shaft.

 

Andy, I've read through a bunch of those threads. What was your final resolution? Any thoughts here?