kvatland

So I just put my truck back together it's an 87 5speed,SAS,22r with 35 tires. My issue is when I'm starting from a stop my whole truck vibrates at low speeds and also when I'm running highway speeds and let off the gas. I just put new u joints in and greased everything I'm not sure what it could be

thefishguy77

iTrader: (1)

If you just put a new U joint in and you know the drive shaft is straight. Could the SAS have lifted it enough to put a bad angle in the rear drive shaft? Just a random question. Is a tire out of balance? Front axle true. Aka not a warped housing if it got gussets. I have heard they can get warped pretty easy if you get them too hot while welding on gussets. Just asking not accusing. Hope this helps.

Edit: is it a 2 piece drive shaft. If so did you separate it? And if you did are you sure you got it perfect going back together? If not it will be out of balance.

kvatland

Tires just balanced. Sas done right no extra gussets. I got a used driveline might have to get it balanced

Teuf

Your problem is probably drive shaft angle as fishguy said. I went through the same issues after I added leafs and longer shackles in the rear to match my front SAS. I ended up adding a CV joint to the drive shaft. Shake 99% gone. [IMG][/IMG][IMG][/IMG]

Teuf

Rear DS with CV.

kvatland

yea i pretty sure its the driveline, i just to it off to go get it balanced, i did notice the rear third has play in it like the backlash is sloppy, i can rotate it 1/8 each direction before tires began to move, and also at highway speeds like 55-65 if i let off the gas it make weird vibration/grinding noise, does it with the clutch in/ in gear and in neutral, any info would be great thanks

thefishguy77

iTrader: (1)

Well that vibration still could be driveshaft. Regardless of neutral clutch or in gear the drive shaft is still spinning with the rear end. You are just disengaging the transmission with neutral or the clutch. Get your driveshaft fixed and see if that solves it. I find its easier to fix one thing at a time. That way you know what solves each problem.

Teuf

Along with the SAS what did you do to the rear suspension?

kvatland

63's with 3 inch blocks, checked my pinion and output angles and they are within 1 degree of being the same is that ok. and i also pulled my third to make sure it looked ok and i think my axle bearings are bad, with the axle shaft out i can wobble the backing plate, there is no in and out movement it just wobbles on the axle shaft is that normal?

Teuf

The 2 illustrations I posted, what does it match? There are 2 angles shown, anything in between will rear its ugly head. Each angle requires a specific u joint setup.

kvatland

the pinion angle is 96 degrees and the output is 96.5 degrees that is almost parallel so that should be fine with a 2 u joint setup right?

bewelch

As you're crossing Tire balance, Alignment, and shaft balance/play, off the list. You may want to consider transfer case bearing, chain slack in the transfer case, and wheel hub bearings.
I have been chasing a vibrating/grinding noise during a rebuild of an '87 4Runner. The noise occurs much more noticeable above 45mph just as I let off of the accelerator to coast or maintain speed.

Teuf

Is the driveshaft in phase?

bewelch

Phase? It has been balance and u joints replaced. We tried swapping end for end… vibration still occurs.

Teuf

In phase / out of phase, I don't have an illustration to show you. You'll need to google that one

Teuf

This shows a square DS. A splined shaft could be off a little and make a big difference. Mine was off 2 splines and shook.