Driveline problem

JACKED944RUNNER · Oct 1, 2007

I sas'ed my 94 4runner used 5" springs had the driveline lengthened and have a bad vibration between 35-60 mph ONLY when I let of the gas and coast.
I have shimmed the rear axle 8 degrees with shims, the blocks I had to use to level it out are angled as well. The driveshaft is in balance as well. I was told to have a C.V. added off the Transfercase to help with vibes. I welcome any input.

84Toyota4x4 · Oct 3, 2007

You need to tell us what type of driveline you have. Is it a single piece with single joints or single piece with CV joints, multi piece, etc? The angles vary from each type of driveline and how youre supposed to have it set up.

~T.J.

JThompson · Oct 3, 2007

I have 4" springs on my rig, and I kinda got the same story, though not as severe? No matter how you shimmed your rear axle, you still have pulled out the spline a little farther. Well, I notice that on an old/high-mileage d-shaft, it is kinda cavetating around inside the slip section....

But, yeah, it is mainly during coast and especially between coast and power...

BTW, does anybody know how a Toy rear shaft is supposed to be angled/shimmed? I swear every toy (especially stock) I look at has the rear (non-CV) shaft pointed a hair below the t-case output. Everybody tells me to have the rear pinion angle equal to the t-case angle, but that is not what I am seeing! My d-shaft, without any mods whatsoever, pointed at the t-case flange... Now that I have rotated it closer to equal angles, it vibrates alot more...?????????:wtf:

zig80toy · Oct 3, 2007

Ok, i ran into this problem as well. As green as i am i thought you could just aim the rear pinion at the t case and call it good. No.
On one hand you think your helping your driveline angle but then you run into these vib problems. I went the expensive route and fixed the problem with a new CV rear driveshaft.

In stock form the output on the t case is level with the ground (plus or minus a few degrees, whatever). Same goes for the rear pinion. Having both thses flanges on the exact same plain is what keeps the smooth ride. When you start angling one or the other you will run into vibs. It can take a little bit of angling without getting vibs but it sounds like you got your pinion pointed too far up.
8 degree shims plus shimmed blocks sounds like too much. how many degrees do you think those blocks are in addition?

zig80toy · Oct 3, 2007

Im not sure how much lift is too much lift for a stock toyota rear driveshaft. If you think you can get away with it i would be tempted to yank out that 8 degree shim and see what happens. I bet your vib problem will go away. However, then you have to worry about your driveshaft binding when your rear axle droops. But you can check that just by jacking it up and letting the axle hang.

The reason i went with a rear CV shaft is because i flatbellyed my 80 toyota as well as added 3" springs. It was about 7 inches different from stock and my t case flange was actually pointed up a little bit. When i put the stock driveshaft back on, holy hell, was there some bad vibrations. After cutting a huge hole in teh floor for the raised drivetrain, patching it, buying a new crossmember, etc.. i didn't really feel like undoing it. So i bought a new rear driveshaft. I'm glad i did though, cause all the vibrations went away.

JACKED944RUNNER · Oct 3, 2007

The driveshaft is flange flange type non CV. I was told by Jesse at High Angle to have the Pinion degrees lower than the Tranfersfer Case When I set my angle. I think the angle on the T-Case was 29 degrees.

zig80toy · Oct 5, 2007

As far as i know all toyota trucks and 4runners have standard non-CV type rear driveshafts.

So what happened? You fix it?

Jay W · Oct 7, 2007

The tc output and pinion flanges need to be parallel or pinion down a couple degrees. If that's too steep then get a CV and point the pinion at the tc.