Driveshaft Angle Help?

Try measuring the t.c. pinion severely times and rock the level a bit to see where flat feels.
I feel like it should read in the 5's

 

Hey all, wanted to give a quick update. Took the axle shims out and wanted to give an update:

TC angle: 4 deg
Front Shaft: 7.8 deg
Rear Shaft: 10.1 deg
Pinion: 5.0 deg

1st working angle: 3.8 deg (7.8-4)
2nd working angle 2.3 deg (10.1-7.8)
3rd working angle 5.1 deg (10.1-5.0)


Here are the new angles, what would you guys reccomend? So from how most people judge it, I would need about a 3 degree shim. However I’m still tripped up on seeing the first two angles added to be equal to the 3rd working angle for no vibes.

I also should note that I had a bunch of axle wrap after the shims, but it went away most of the way, though there a little. Still think there’s some sort of vibes though, especially at highway speeds. I should also note that the toytec shim I had seemed to have deformed a degree because it was almost as if the threads of the centering pin were pressed into the shim’s hole lol. If I get another one it’ll definitely be a Tom woods steel one or something to that degree.


Would you guys recommend maybe trying a 2.5 degree shim based on these measurements? Is that likely to fix a lot of the vibes and axle wrap being only 0.7 deg apart, and accounting for pinion rise? Or should I put the carrier bearing drop kit I have back in to see what that does? I just feel like it would increase my first working angle, though i don’t know how much.

thanks for your input thus far!

 

Not really sure how you are measuring these. Forget about measuring the TC angle. If it is all stock angles, there is nothing wrong with it.

The difference in angle between the front half of the rear driveshaft is your first angle. Using a phone level, just measure the front and the rear driveshafts. The difference is your first angle. The difference between the rear driveshaft and the pinion is the second which is a little harder to get. You can use a square held against the flange and then measure the bottom of that.

I'm assuming that your 2nd and 3rd listed above reflect those 2 angles. So a 3 degree shim should make the difference 2.3 to 2.1, which should be good.

 

So I measured these with a magnetic angle cube. Measured on the machined surface on the yoke connected to the transfer case. Then on each half of the driveshaft, making sure they were centered, then measured the pinion on that machined part of the yoke connected to the pinion. I almost wonder if it was the shim or something, I’m confused as to why I had vibes and axle wrap with a 3 degree shim if that’s what it seems like I should have.

 

I guess I'd need a drawing of what you are measuring. You don't have a carrier bearing drop, do you? That 2.8 degree difference in the rear angles is way too much. The 3.8 degree at the front looks high to me.

 

Yeah I mean I think I understand how it’s supposed to be, but hearing conflicting information is always confusing.

I’ll see what I can whip up. My understanding was that since the yoke is a continuation of the transfer case, using it as a reference point to measure angle, in conjunction with the pinion was acceptable. I don’t have a carrier bearing drop in at the moment to answer your question, though I do have the kit. Just took it off when experimenting. I also agree 3.8 does sound pretty high for a factory determined angle…

 

For what it is worth, my lift seems to be about the same and my symptoms were similar. I tried the CB drop first, then added the 3 degree shim, then removed the CB drop to get my angles even in the rear. I didn't even measure at the transfer case since I didn't change anything there. That joint doesn't really move much since the front driveshaft is held in a relatively static position. I drive lightly and have no vibes. If I get on it hard from a light, there seems to be a little vibe just briefly, but I can't say that is due to the driveline.

I'd personally put the shim back in and measure. That seems like it would get you within 0.2 degrees. If you still have vibes, start looking at other things.

 

Thanks for your input. So you have around 3 in the front 2.25 in the back? And found that a three degree worked the best for you? Did you use a steel or aluminum shim?

I may try remeasuring on a different surface again this weekend before I get another shim kit. I definitely think that when I’d put another shim in, it’ll be a steel one. But I agree with you, those angles would be pretty darn close to zero. Or would it be better to keep the pinion at 0.7 degrees different with a 2.5 deg shim in order to account for the pinion rising under torque?

 

Out of curiosity, what are your hub to fender flare measurements? And/or base of bumpstop to frame?

 

this tsb may help as it has examples of how to measure various angles. numbers are for unlifted so ignore that.
https://static.nhtsa.gov/odi/tsbs/2020/MC-10187246-9999.pdf

 

I’ll have to wait till I get my measuring tape, but I’ve got 255/80/R17 tires and 3 inch ish front lift and 2.25 inch ish lift back… if that helps any. Lol

 

The lift height advertised by manufacturers is just a rule of thumb at best. You have to actually measure it to know. I’m curious because I have a similar lift, a OME carrier bearing spacer, and no vibration issues.

FYI: These are my rear hub to fender measurements:

RL 23
RR 23.5

 

Yup you're exactly right. I'll definitely measure as soon as I'm able.

Do you have RXT leaves?

I have that same carrier bearing spacer but it's currently off. I may put it back on and remeasure angles. Did you ever measure your angles? The only thing about doing the CB drop is that it increases the first joint's working angle...

 

I have OME Dakar medium leafs. I never measured my driveshaft angles.

 

It's hard to say what I would have with no weight -- I have about 500 lbs. over the rear axle. I was already sagging a bit. I got about 3" rear and 2.5" front.

I'd just try to get them as close to even as possible. Remember that under engine braking, you have the opposite going on. My vibes were actually more noticeable when coming to a stop.

 

Thanks for all your input, I really do appreciate it. I wanted to ask- how many of you guys with the same amount of rear lift height ended up running axle shims with the carrier bearing drop kit? From how my angles look it seems like I’d want to just do shims because my 1st working angle would probably be 5 or more degrees, wearing out the joint faster… right?

Perhaps I’ll measure again this weekend and park somewhere else to take measurements. Also, I’ll try measuring the flanges instead of the yoke to see if that yields any difference.

In the end, I’ll probably end up with some kind of steel shin back there…

 

With all do respect, unless I missed it, you haven’t told us how much lift you have. You only mentioned the type of leaf pack you have.

 

I said it up a little bit, in case you missed it, i have 3” front and 2.25” in the rear without any kind of shim. That’s advertised lift, probably this weekend when I have time I’ll get some hub to fender measurements

 

Like I said, you didn’t tell us how much lift you have. You told us what type of leaf pack you have. Sorry, but it’s true that advertised lift heights are highly inaccurate in general (33-40% off). It’s not all their fault. The actual lift height depends on a number of factors, for example the weight of the truck. You estimate could be decently accurate, but it only takes 10m to verify it.