Help with Drive Line Vibration

Posted By: Mopar_Mudder

Help with Drive Line Vibration - 05/20/13 04:06 PM

I know I have read some post on firuring out what you need to change for pinion angle to fix vibration but I can't find it.

I have a TKO-600 in a 1971 Cuda. For initial set-up I have the tranny at 3-1/4 deg down the the pnion at 0

I have no vibration going down the road until about 70mph.
I have no vibration under decel
I don't think thier is any vibe under hard accell, but it is hard to tell as the power coming out of the Hemi seems a little violent making vibrations hard to pick out.

What I do have is a pretty good vibration when I push the clutch in and coast down the road. The same vibration when going down a hill and off the gas. Aslong as their is back pressure on the drive line it is gone.

I was going to get some shims to turn the pinion, any good guess on which way to go.

Posted By: stumpy

Re: Help with Drive Line Vibration - 05/20/13 04:45 PM

This from the tech archives might help.The tech Archives are a great place to get info. http://www.moparts.org/Tech/Archive/rearsusp/13.html

Posted By: RapidRobert

Re: Help with Drive Line Vibration - 05/20/13 08:09 PM

From prior posts I gathered if the trans is 3 &3/4 deg down then you want the pinion 3&3/4 up then lower it ~2 deg from there as the pinion will climb on accel so that'd be 1&3/4 up on the pinion. Maybe the trans being 3&3/4 down is too much to start with & it needs to be raised some for a starting point

. I'd wait for the Doc or someone that knows what they're doing to chime in. I had a 1/2 ton 77 dodge pickup used for hauling that would vibrate on decell ONLY when extremely loaded down with debris so yes it was the pinion angle that was changed from the spring load. 8&1/4 iirc. EDIT I reread your post & it might actually be the gearset

Posted By: loaderpro

Re: Help with Drive Line Vibration - 05/21/13 12:45 AM

never mind what the trans is doing...level the driveline to zero at ride height...then set the pinion at 6-8 degrees nose down for leaf springs.

Attached picture 7713123-pomona.jpg

Posted By: DAYCLONA

Re: Help with Drive Line Vibration - 05/21/13 01:55 AM

Quote:

I know I have read some post on firuring out what you need to change for pinion angle to fix vibration but I can't find it.

I have a TKO-600 in a 1971 Cuda. For initial set-up I have the tranny at 3-1/4 deg down the the pnion at 0

I have no vibration going down the road until about 70mph.
I have no vibration under decel
I don't think thier is any vibe under hard accell, but it is hard to tell as the power coming out of the Hemi seems a little violent making vibrations hard to pick out.

What I do have is a pretty good vibration when I push the clutch in and coast down the road. The same vibration when going down a hill and off the gas. Aslong as their is back pressure on the drive line it is gone.

I was going to get some shims to turn the pinion, any good guess on which way to go.

Generally the pinion rotates upward on acceleration anywhere from 2-4 degrees, with your pinion currently at 0, your dialed-in pretty close in your static "set-up", but seeing that your experiencing vibration in the DE-acceleration/coast mode, that indicates the pinion isn't rotating upward enough, buy the MP axle shim kit, add 1 to 2 degrees, rotating the pinion upward, your current spring set up may not allow the housing the rotation and or U joint phasing it needs to cancel out vibration,....FYI just make sure the pinion snubber isn't affecting the housing rotation....esp if the vehicle is lowered

Mike

Posted By: jbc426

Re: Help with Drive Line Vibration - 05/21/13 10:32 AM

Your pinion is -3 1/4 nose down relative to the engine/trans centerline. What type of rear suspension do you have?

Have you tried rotating your driveline 180 degrees and reinstalling it? Measure the runout of your axle flanges, try a different set of tires/rims and see if it changes?

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 05/21/13 03:07 PM

Rear suspension is all set-up as stock, now lowering of anyhting. The rear springs are from PST Suspension and are suppose to be reproductions of the original HEMI springs.

The rear axle is a new/converted truck Dana 60. Originally when I got it it was set-up with the pinion about 8 deg down but that just went against everything I know about drive lines, equal but opisite angles. I can see if for drag racing maybe but under normal driving down the road the pinion would have to rotate up 11.25 degs to equal out, that just isn't going to happen.

I haven't tried anything yet, my first though it rotate the pinion up another 2deg and see what happens. I can try swithing the drive shaft 180 also, good idea.

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 06/25/13 06:40 PM

Wanted to update what I have done and where I am at.

I thought I had fixed the bad vibes. Went to start shiming the rear pinion and noticed that the rear u-joint seems loose. Well seems I had a 1350 yoke and a 7290 joint

So I got a new yoke and the vibe I had went away totally and all seemed to be fine. So I thought I was vibration free, well atleast as much as I can tell above the drone and vib of the TTI exhaust

This weekend I got out on the freeway for the first time and found out that I have a vibration starting between 65-70, up to that point it seems smooth. If you let off the gas it goes away, and pushing in the clutch it is gone.

Guess it is time to start shiming, I must be close since it doesn't start until higher speeds.

Posted By: RapidRobert

Re: Help with Drive Line Vibration - 06/25/13 10:30 PM

Quote:

that the rear u-joint seems loose. Well seems I had a 1350 yoke and a 7290 joint

Are you saying that the 1350/7290 ain't compatible? Any possibility that the improper excessive clearance fubared the ujoint (in addition to the yoke you replaced)?

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 06/25/13 10:50 PM

I don't think so, only had about 20 miles on it that way. Was good and tight when I put it together with the correct yoke. I will double check it though when I jack it up to work on shims.

Posted By: Cab_Burge

Re: Help with Drive Line Vibration - 06/26/13 02:30 AM

Try putting the shims(2 or 4 degrees) under the rear of the saddles welded onto the axle tubes first

This subject, pinion angle and trans and driveshaft angles has been beat to death, bottom line, find out what works best on your car

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 06/26/13 02:13 PM

Quote:

Try putting the shims(2 or 4 degrees) under the rear of the saddles welded onto the axle tubes first This subject, pinion angle and trans and driveshaft angles has been beat to death, bottom line, find out what works best on your car

Yep, thats my plan

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 08/06/13 06:07 PM

Another update:

Added a 1 deg shim to the axle bringing the pinion up. Seemed to help, vibration less sever and at a little higher speed.

Added another 1 deg to the mix, vibration at a little higher speed again but still their. Now I am getting quiet a bit of vibration on hard accel also. So while moving it up seems to help at speed it is making it worse under acell.

Right now the tranny is 3.7 down, rear end is 2.5 up and the drive shaft is .5 deg going up toward the rear end.

Posted By: JohnRR

Re: Help with Drive Line Vibration - 08/06/13 09:21 PM

Quote:

Another update:

Added a 1 deg shim to the axle bringing the pinion up. Seemed to help, vibration less sever and at a little higher speed.

Added another 1 deg to the mix, vibration at a little higher speed again but still their. Now I am getting quiet a bit of vibration on hard accel also. So while moving it up seems to help at speed it is making it worse under acell.

Right now the tranny is 3.7 down, rear end is 2.5 up and the drive shaft is .5 deg going up toward the rear end.

before you said the trans was 3.25 down , why is it lower?

Posted By: DAYCLONA

Re: Help with Drive Line Vibration - 08/06/13 09:22 PM

How much "end play" do you have in the drive shaft?, make sure it has at least 3/4" travel on the yoke before it bottoms on the transmission's output shaft, hard acceleration will rotate the pinion higher as spring wrap up encourages it, plus sticky tires further increases it, as well as moving the driveshaft forward, compressing it inside the tailshaft, if it's bottoming out, this can be another source of driveline vibration, not to mention component failure as well...

Mike

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 08/06/13 09:52 PM

Quote:

Quote:

Another update:

Added a 1 deg shim to the axle bringing the pinion up. Seemed to help, vibration less sever and at a little higher speed.

Added another 1 deg to the mix, vibration at a little higher speed again but still their. Now I am getting quiet a bit of vibration on hard accel also. So while moving it up seems to help at speed it is making it worse under acell.

Right now the tranny is 3.7 down, rear end is 2.5 up and the drive shaft is .5 deg going up toward the rear end.

before you said the trans was 3.25 down , why is it lower?

Just a difference in how the car is sitting on stands. I didn't have it block up exactly the same as I did the first go around. The 3.25 is actually closer to a actaul angle with the car sitting level. When I did it this week end I had the car sitting a little lower in the back then the front.

Also the first measurement we with an analog swinging pointer type deal. I have a digital one now that is more acurate.

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 08/06/13 09:55 PM

Quote:

How much "end play" do you have in the drive shaft?, make sure it has at least 3/4" travel on the yoke before it bottoms on the transmission's output shaft, hard acceleration will rotate the pinion higher as spring wrap up encourages it, plus sticky tires further increases it, as well as moving the driveshaft forward, compressing it inside the tailshaft, if it's bottoming out, this can be another source of driveline vibration, not to mention component failure as well...

Mike

End play is fine. The drive shaft will actually hit the back of the shift linkage before it will bottom out. It is very noticable when it hit, the noise and the fact it will bump it out of gear. So I know that is not an issue.

I know the vibration under power is do to pinion wrap up, but if I lower the pinion it vibrate when driving normal.

Also forgot to mension the pinion snubber is only about 3/4" from hitting the floor, seems tight.

Sure is fun to chase these things

In my SRT-10 ram I know the pinion climbs a bunch under big power. But that thing is smooth as silk all the time. Don't know why the Cuda is so tuchy, maybe the shorter drive shaft????

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 10/28/13 03:02 PM

Another Update, I did some more testing this week end.

I tried something different and shimed the pinion down 3 deg instead of up. It is exactly the same as before. Smooth up to 65-70 then is vibrates, but if you let of the gas the vibration is gone.

So just to refresh memories the tranny is 3.7 down and I have tried the pinion at

+2.5
+1.5
0
-2
-3

All seem to act exactly the same, which make no sense. Guess I need to look into get the drive shaft checked next. It might have to wait until spring.

Posted By: RapidRobert

Re: Help with Drive Line Vibration - 10/28/13 03:12 PM

Quote:

I have tried the pinion at

+2.5
+1.5
0
-2
-3

& changing that angle is labor intensive, hopefully Mr Murphy will leave you be for awhile after you get this taken care of. yes I'd balance the shaft/check the ujoints/yoke

Posted By: DAYCLONA

Re: Help with Drive Line Vibration - 10/28/13 05:12 PM

Quote:

Another Update, I did some more testing this week end.

I tried something different and shimed the pinion down 3 deg instead of up. It is exactly the same as before. Smooth up to 65-70 then is vibrates, but if you let of the gas the vibration is gone.

So just to refresh memories the tranny is 3.7 down and I have tried the pinion at

+2.5
+1.5
0
-2
-3

All seem to act exactly the same, which make no sense. Guess I need to look into get the drive shaft checked next. It might have to wait until spring.

What's the "history" of the shaft?, isn't that part of the Hurst kit...or?

Posted By: Tom_440

Re: Help with Drive Line Vibration - 10/28/13 05:18 PM

Maybe double check the condition of the trans mount?

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 10/28/13 05:41 PM

Quote:

What's the "history" of the shaft?, isn't that part of the Hurst kit...or?

The shaft is brand new from Inland Empire Driveline.

The tranny mount is new polyuretheane, thinking about repacing it for a rubber one.

Posted By: DAYCLONA

Re: Help with Drive Line Vibration - 10/28/13 10:12 PM

Quote:

Quote:

What's the "history" of the shaft?, isn't that part of the Hurst kit...or?

The shaft is brand new from Inland Empire Driveline.

The tranny mount is new polyuretheane, thinking about repacing it for a rubber one.

I've always run the poly mount on TKO swaps, no issues...I'd ask Inland Empire what there balance speed is when they balance a shaft,...suprisingly most shops only balance up to 3500 RPM,....you want a shop that can balance up to 10,000 RPM shaft speed, for a TKO application

Mike

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 10/29/13 01:00 AM

I actually want to try the rubber mount to see if it will get rid of another RPM related vibration. Guess I would really call it a vibration maybe more of a harmonic thing. Starts about 3000 rpms in all gears or neutral even. But from out side the car things all seem pretty smooth.

I want to get the drive shaft checked. But I have been putting it off because I have to pull that exhaust apart to get the shaft out. And getting the exhaust apart is hell and then some

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 10/29/13 09:05 PM

Quote:

I'd ask Inland Empire what there balance speed is when they balance a shaft,...suprisingly most shops only balance up to 3500 RPM,....you want a shop that can balance up to 10,000 RPM shaft speed, for a TKO application

Mike

Inland maxes out at 3500 they said, not that they balanced it that high.

Called a couple shops around here and most balance at 500 maybe 2500. They never heard of balancing that high

Posted By: DAYCLONA

Re: Help with Drive Line Vibration - 10/29/13 10:00 PM

Quote:

Quote:

I'd ask Inland Empire what there balance speed is when they balance a shaft,...suprisingly most shops only balance up to 3500 RPM,....you want a shop that can balance up to 10,000 RPM shaft speed, for a TKO application

Mike

Inland maxes out at 3500 they said, not that they balanced it that high.

Called a couple shops around here and most balance at 500 maybe 2500. They never heard of balancing that high

Keisler balances all their shafts at 10,000 RPM, they are one of only a handful of shops with the capability, most shops are only using conventional lathes to balance their shafts, very few actually invest in dedicated balancing equipment

Mike

Posted By: Supercuda

Re: Help with Drive Line Vibration - 10/29/13 10:01 PM

Quote:

you want a shop that can balance up to 10,000 RPM shaft speed, for a TKO application

Mike

Why?

That would be 8200 rpm engine speed in 6th and there is no way your drive shaft will ever see 10000 rpm in any other gear (or in 6th for that matter).

Posted By: Supercuda

Re: Help with Drive Line Vibration - 10/29/13 10:03 PM

Quote:

Keisler balances all their shafts at 10,000 RPM, they are one of only a handful of shops with the capability

Yes and we all know that the Gospel according to Keisler is the truth, the whole truth and nothing but the truth.

I wouldn't believe Kiesler if they told me water was wet.

Posted By: DAYCLONA

Re: Help with Drive Line Vibration - 10/29/13 10:06 PM

Quote:

Quote:

you want a shop that can balance up to 10,000 RPM shaft speed, for a TKO application

Mike

Why?

That would be 8200 rpm engine speed in 6th and there is no way your drive shaft will ever see 10000 rpm in any other gear (or in 6th for that matter).

What about a .50 OD application?...

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 10/29/13 10:26 PM

Quote:

Quote:

Quote:

you want a shop that can balance up to 10,000 RPM shaft speed, for a TKO application

Mike

Why?

That would be 8200 rpm engine speed in 6th and there is no way your drive shaft will ever see 10000 rpm in any other gear (or in 6th for that matter).

What about a .50 OD application?...

Actually drive shaft speed is dictated by gear ratio and tire size.

Lets see 10,000 rpm with a 4:10 gear and my F60-15's would be 188 MPH and 6400 rpm on the engine. (this is baced on a .64 OD )

Yes the pucker factor would be HIGH

Posted By: Supercuda

Re: Help with Drive Line Vibration - 10/29/13 10:47 PM

Quote:

Quote:

Quote:

you want a shop that can balance up to 10,000 RPM shaft speed, for a TKO application

Mike

Why?

That would be 8200 rpm engine speed in 6th and there is no way your drive shaft will ever see 10000 rpm in any other gear (or in 6th for that matter).

What about a .50 OD application?...

Did the TKO600 come with a .5 OD ratio?

I see a .82 and a .64, no .50

What road speed would you be doing at 5000 engine rpm in OD? or 6400 engine rpm?

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 10/29/13 10:55 PM

Quote:

What road speed would you be doing at 5000 engine rpm in OD? or 6400 engine rpm?

My numbers in above post are based on a .64 OD

I know what you are saying that you will never see that speed. But it would stand to reason that faster you spin the shaft the more acuraccy you would see in balancing it.

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 11/04/13 04:46 PM

Another update.

I installed a stock rubber tranny mount yesterday. Looks wimpy compared to the poly one but I put it in anyways. It did seem to change the vibration some. It is not as high of pitch/frequency now, a little bit lower. I don't know that it help it or is just masking it so you don't feel it as much. Also in the past I have noticed that the vibration get worse as the further you drive and get stuff warmed up more. It was only 45 degs last night so I am sure things didn't get warmed up as much, but I was able to go 80 with out feeling like I was pushing it too hard.

I think I am going to work on exhaust next. I notice that a drone in the exhaust actually comes in about the same time as this vibration, wonder if the two could be related some how? Have to try an figure a way to get a resinator in the exaust, not much room to do it....

Also I checked the drive shaft for run out while I was at.

Rear = .014
Middle = .0075
Front = .009

Posted By: RapidRobert

Re: Help with Drive Line Vibration - 11/04/13 10:39 PM

Quote:

Also I checked the drive shaft for run out while I was at.

Rear = .014
Middle = .0075
Front = .009

the numbers APPEAR to be low but you might call a driveline specialty shop & run it past them what's going on & see what they say

Posted By: Mopar_Mudder

Re: Help with Drive Line Vibration - 11/04/13 11:12 PM

Quote:

Quote:

Also I checked the drive shaft for run out while I was at.

Rear = .014
Middle = .0075
Front = .009

the numbers APPEAR to be low but you might call a driveline specialty shop & run it past them what's going on & see what they say

Yea I am going to get rebalnced again. But they are talking 4-6" of snow tomarrow night. So I think I am done until spring now.....

Posted By: RapidRobert

Re: Help with Drive Line Vibration - 11/05/13 01:56 AM

they're all going to say bring it in & lets balance it. Hopefully you can find one that's honest about it otherwise you'll pay for another balance job & that wont fix the problem cuz it's balanced OK right now but people have reported on occaision in severe cases that it took several different shops till one of em got it right. Holler how it goes.