Mr_president

iTrader: (38)

ok i have a vibration at 75 on gets harder as speed goes up .. in my car i have put a few differnt set of tires i have orderd a new drive shaft i have tried couple differnt u joints and if its not the pinion agle i dont no what it is please help......


also looking for good pinion agle for stip and everyday driving with no vibration!?

EPP

iTrader: (22)

-2 degrees is a great all around setting. Bob

chicane

First, measure your transmission (output shaft) angle..... and match the differential pinion angle to that.

So, lets say you measured 3.5* down..... then the differential pinion angle should be set to 3.5* down. It basically has to be equal and opposite in both angle to be vibration free.

Factory is 4*. If you have changed to poly mounts, engine and transmission, you can get away with less. On a manual transmission chassis I have gotten them to work with angles down to around 2-2.5*. With an automatic transmission, they tend to want a little-bit more.... around 3-3.5.

pla-tym

If you measure your driveshaft angle, it should be somewhere close to 1 1/2 degrees negative. If you set your pinion angle at 90 degrees, then your total pinion angle should be 1 1/2 degree negative. Your pinion angle is set in relation to the driveshaft angle.
Example: If driveshaft is 1 1/2 degree negative and rear end pinion angle is 1 degree negative, your total pinion angle is 2 1/2 degree negative.

CamTom12

iTrader: (1)

I've tried 5 or 6 different pinion angles from +3 to -3 and anywhere in between... This vibration isn't just driving me nuts, it's tearing my tranny apart... I can't pull the tranny out of 4th at the top end of the track, and now my. At least I'm not the only one that's got the problem. Might it be something wrong inside the center section? I know I've personally been having horrible luck with mine.

Mr_president

iTrader: (38)

well now my tranny is gone and now my rear end hits the top of my car and makes a loud banging noise ,when i let off and take off ... what the hecckkkkkk!!! however i do not have a adjustable pan hard, yet will that do the trick??

Mr_president

iTrader: (38)

pan hard is in still no luck ......... i absolutly hate the way my car drives , its got me on prozac!! i have changed the tires i have changed the drive shaft i have got a new trans what the heck is this crazy problem!

oange ss

iTrader: (50)

maybe wore out output shaft bushing in the tranny

01350ss

iTrader: (18)

thats what I was going to say, however, "new trans" kind of negates that idea

01350ss

iTrader: (18)

by the way i have the same damn problem. i'm still trying to figure it out myself.

peterock98

iTrader: (25)

If you have the spohn floor mounted tq arm that's the problem.Set the pinion @-1.

Mike2000Z28

I have the same problem, as time when on with replacing the same things that you have (aluminum DS, bearings in rear, gears, axles, and finally tire rebalancing) I still have the same problem. It has gone from not driveable to almost unnoticeable but still at 75mph I get a slight vibration. I'm hoping the vibration is left is that the new ujoints got messed up before I had the tires rebalanced. I dunno how new the rearend is but if the wheel bearings are bad or that the shafts are bent. I understand that it is a ford 9", once I replaced my wheel bearings and axles the car got noticeably better then before. My pinion angle was dead on where it needed to be, so I would start there and then start looking at the rearend itself.

I know that doesn't help all that much and is not that technical but I (like you) do not want to throw money and our daily ride time away at parts that are not working out.

mike#9

iTrader: (3)

I had the same type of vibration after breaking a driveshaft on the dyno. We found that I had a bent main shaft in the tranny. I would check that for the hell of it. My car started at about 55 mph or so and got progressively worse as I went faster. After 100 or so...it felt like my doors were going to fly off because all of the shaking and vibration.

Mr_president

iTrader: (38)

wouldnt they notice this stuff with the new tranny rebuild??!? also were is the output shaft bushing located because maybe ill buy a new one and have it put in

mike#9

iTrader: (3)

Were you getting this vibration before the tranny rebuild?

Mr_president

iTrader: (38)

yes before I had my tranny it vibrated

CAT3

iTrader: (9)

Are you using the poly trans bushing? I had a slight vibe at 75, then took the spacer plate out, as recommended was to have it in. Went for a ride and almost vibe free. Still a slight one around there, but oh well. I probably have bent every shaft in the trans and both axles, that'd be my luck.

Mr_president

iTrader: (38)

lol cat3 were in the same boat all that would be my luck

Mr_president

iTrader: (38)

soo does anyone like to race soo much and love to improve your car soo much you make your self sickk?? just curious

CAT3

iTrader: (9)

Everyday....more sick since I blew the trans for the second time, so no bullshitting this time... Rossler TH350 w/ Rossbrake, 4k Stall, Pro Ratchet shifter will be going in. Until it arrives, about another 6days hopefully, I'll be curled up like a 10y/o pimple faced geek with the flu! Good luck with the vibes. Hell, not I cant even say the spacer removal was an issue, as much as I recall. Its been two weeks already.