Rear driveline angle Q

heep70 · Oct 23, 2006

I have an 80 shortbed Toy. It has the dual cases and the rear axle is moved 1" back. 6" lift. The rear driveline is 43.5" long from flange to flange.

This angle reading are as close as I can get.

The rear pinion angle is +12 degrees (pointing up).
The driveline is +16 degrees (towards t-case).
The T-case is 2 - 3 degrees negetive (rear flange pointing down).

Do I need to improve theses angles? Which ones and how much?

I also have a thread started on getting a CV put into the rear shaft.

I am getting extreme vibrations. The sound is simular to the sound of the manual tranny when starting off in to high of a gear. Or when slowing down and then accelerating without downshifting. Gears chatter(?). Everything is rebuilt, so I am, as of right now, not blaming the tranny.

zig80toy · Oct 23, 2006

The vibs are coming from your driveline angle. All you have to do is get a CV driveline and all the vibs go away. I went through the exact same thing. I changed the t case angle and when i put the driveline back on i could not go over 5 mph without the truck shaking violently. When i bought a new CV rear driveshaft all the vibs went away. I responded to your other thread as well...

heep70 · Oct 23, 2006

So the angles I posted are fine?

If adding a CV shaft is all I need, I am all over it.

My daughter won't even ride with me now

skrause · Oct 23, 2006

Ya, it should take care of most of your vibes. Also check your ujoints for problems, I had one that was nice and tight on the truck but later once the needles failed and it got loose I found it to be the cause of a TON of vibes that had been getting worse over time.

zig80toy · Oct 23, 2006

I dont know about "all your angles" being fine or not. We need crash or someone in here to explain more...
I do know that the stock toyota transfer case rear output is exactly parallel with the pinion flange on the rear diff. When you change one of those angles without compensating at the other end you will get vibs with the stock driveline. Best solution in my opinion is to buy a CV type driveshaft. I was told this eliminates the need to worry about "any" angles. Now i know some angles would be considered to extreme, some better than others, or whatever, and thats where i'm kind of lost.

heep70 · Oct 23, 2006

Thanks. I am hearing the same answer about just adding a CV from some shops.

skrause · Oct 23, 2006

zig80toy said:
I do know that the stock toyota transfer case rear output is exactly parallel with the pinion flange on the rear diff.

No it's not.

zig80toy said:
Best solution in my opinion is to buy a CV type driveshaft. I was told this eliminates the need to worry about "any" angles.

No it doesn't. Not unless you put a CV at both ends. Two entirely different setups. With two single cardans you want them to be parallel UNDER LOAD. with a double-cardan at the tranny end you want the pinion to point directly at the output UNDER LOAD. To do this you simply shoot for a couple degrees under at rest, it'll wrap up into alignment with a leaf suspension when you hit the gas and be vibe free.

heep70 · Oct 23, 2006

skrause said:
No it's not.

No it doesn't. Not unless you put a CV at both ends. Two entirely different setups. With two single cardans you want them to be parallel UNDER LOAD. with a double-cardan at the tranny end you want the pinion to point directly at the output UNDER LOAD. To do this you simply shoot for a couple degrees under at rest, it'll wrap up into alignment with a leaf suspension when you hit the gas and be vibe free.

Two of them, wouldn't that be a bit extreme for what I have as far as angles?

skrause · Oct 23, 2006

heep70 said:
Two of them, wouldn't that be a bit extreme for what I have as far as angles?

A bit silly perhaps, just trying to prove a point with what he said. Put a CV at the top, your driveline angle may go up about a degree. Then test it out, if it still vibes a bit you can get a set of steel shims from Roger Brown for the axle, 4* should do it.

zig80toy · Oct 23, 2006

skrause said:
No it's not.

Actually, thats the only thing i'm sure about. Also notice the proper geometry is to have the transfer case output and axle exactly parallel...

zig80toy · Oct 23, 2006

Rather than just that little picture here is the link. This will explain...
http://www.4x4wire.com/toyota/tech/driveline/

heep70 · Oct 23, 2006

I talked to Highangle and he said the only angle with a CV shaft to be conserned about is that the rear pinion be in line with the driveshaft as close as possible.

skrause · Oct 23, 2006

zig80toy said:
Actually, thats the only thing i'm sure about.

Did you even read your own post???

zig80toy said:
I do know that the stock toyota transfer case rear output is exactly parallel with the pinion flange on the rear diff.

It's not bang on exactly parallel. Leaf suspensions flex under acceleration and decelleration, it will never be ideal 100% of the time. It is best IMO to shoot for it being as close as possible when under load. There is theory, and there is real world. I think you need to spend some time trying things out before preaching to the choir, I speak from personal experience not links.

skrause · Oct 23, 2006

heep70 said:
I talked to Highangle and he said the only angle with a CV shaft to be conserned about is that the rear pinion be in line with the driveshaft as close as possible.

Exactly.

For local check with Aukeen, they may also be able to do it for you but you may have to take care of clearancing the joint yourself. There's a writeup on both pirate and 4x4wire with pics of what to do, very easy job.