F0x Slaughter

I put a S60 in the rear and new driveshaft.

Had vibration at 80+ the other day with 0* pinion or so I thought.
So today I adjusted the u joint bolts and set it to -1*.
Vibration moved to 90+.

Well I was measuring off the driveshaft and the torque arm mount on the rear end.

Further reading says use the crank pulley.
So I looked at the crank pulley and it looks like 2*.
Meaning my trans is pointed up.
I have 109K and believe motor mounts are stock.
Could the mounts be sagging giving the engine a positive angle?

1toofastlt1

iTrader: (4)

How does the trans mount look.

F0x Slaughter

Stock and squishy haha.

Didn't even think about that when I put the trans back in.

I should probably change that, since its super easy.
If the engine goes back to -2* degrees then pinion angle should be also -2* correct?

unioncarpenter84

iTrader: (22)

ya thats what im thinking my problem is
is the motor mounts i think there factory

F0x Slaughter

Hm having thoughts. Transmission angle is suppose to be positive.
So I recorded a 2* on my transmission. The pinion is -2* degrees. Subtract the two makes 0*.

I will try setting the pinion to -4* giving me a -2* pinion angle.

ThoR294

iTrader: (6)

time to get my angle finder again... lol

SoxXpupPeT

iTrader: (34)

Definitely do yourself a favor and get a poly mount. Dont listen o people saying "oh itll increase interior noise" It doesnt matter. I bought a brand new rubber one and it lasted me all of 3 days before ripping in half. It was making all sorts of noises throughout my drive train. I would replace that first and then double check your measurements. Should be around -2* BMR has a nice video of how to set it

Monzsta

You want the pinion to be -2 to -4, even -6 if it's smooth. It should have to climb to -2 to 0 under full power and traction. Zero to positive pinion angles are bad. I'd get a stack of washers and put them under the trans mount s few at a time to get rid of the rumble. Or a tubular adjustable torque arm works too.

As a side note make sure your U joints are in good shape, and centered with the proper c clips. If the original driveshaft had the joints changed make sure someone didn't spread the yokes on the driveshaft. This will put the shaft off center causing an imbalance issue. (rumble at speed.)

To be clear on pinion angle, using an angle finder, hypothetically lets say the incline of the transmission output shaft is 90 degrees. Perfectly level. The incline of the pinion of the rear end is 92 degrees. Relative to the transmission, it's pointing down 2 degrees, so your pinion angle is -2. If it were 90 degrees also, then there's your 0 pinion angle. If say it were 88 degrees, it would be pointing up 2 degrees so it would be +2. Pointing the diff down would give you negative pinion angle. Pointing the transmission tail up (with shims under the mount) also gives you negative pinion angle. Bad pinion angles are more noticeable under acceleration and go away under deceleration. A poorly balanced or off center driveshaft just vibrates all the way around.

gjohnsonws6

iTrader: (12)

You are making this way over complicated. Pinion angle is pinion angle and that's it. Put the car on ramps at all four with at least a half tank of fuel and someone in the drivers seat. Also make sure the rear is centered with the frame.

F0x Slaughter

I should center the rear I have adjustable panhard bar, adjustable UMI torque arm, just ordered adjustable LCAs as I just have tubular ones.

ThoR294

iTrader: (6)

I have the same stuff you have. I have adj LCAs and relocation brackets for them sitting on my shelf

Low N Slow

iTrader: (4)

Sometimes a picture is worth a thousand words.

F0x Slaughter

That only makes sense on factory cars with 0*.

Say the trans is 2* positive you wouldnt want the pinion 2* positive, they would both be pointing up. One has to point up, the other down.

armyinfantry3id

[QUOTE=guppymech;17284185]Maybe this info will help.
http://www.hurst-drivelines.com/file...roc_111606.pdf


i just read this entire article, there is some awesome information there! thank you very much for posting that link

BALLSS

GM made spacers to put between trans & mount. washers would also work but these are 'slotted" and just slide in when ou losen the mount bolts and lift up rear of tranny.

I had one but added the 2nd to dial in my DL angle

ThoR294

iTrader: (6)

I have a spacer that came with my aftermarket poly mount.... hmmm

F0x Slaughter

I just got my poly mounts today.

Also Guppy thanks but I already read those articles and posted it in Thors thread.

My vibration only happens past 90mph now.
Going to put in poly trans (motor mounts later), adjust pinion angle more, check driveshaft run out.

unioncarpenter84

iTrader: (22)

my poly one came with that spacer but once i took the spacer out it wasnt as bad but still bad at 70

F0x Slaughter

Well today I correct the front ride height, coilover was low on the passenger side so matched it with driver side, centered the rear end with the panhard bar, tipped the pinion angle to -2 to -3.
Haven't put the poly mounts in yet.

The vibration is still at 90+. I can feel it in the shifter its not like the whole car shakes and but I can still feel it slightly. It also is while coasting.

Going to check the driveshaft for runout, flip it 180* check it again set if the driveshaft is messed up or if a yoke is.

armyinfantry3id

if your feeling the vibration while coasting i would say have your rear tires balanced and check the rims to make sure they are not bent or dented