Tremec vibration

[ChargerKen]

I have a 68 R/T I installed the tremec TKO 600 5 speed in. I have a bad vibration from about 60 mph up. Using Tremec's own  phone app I measured the driveline angles and they were out of  spec. I cut my tunnel and raised the transmission 1". Using the app it shows everything is corrected. I might add that everything underneath is much better as well. Z bar, exhaust, headers all tucked up nice. I drove it today only to find the vibration hasn't went away. Upon looking at the tailhousing with the slip yoke instslled there seems to be a goodbit of radial movement at the tailshaft. Does anyone know what an acceptable amount of radial play would be for this? Any other direction on how to solve my vibration dilemma? 440,tremec tko 600, new Strange Dana 60, 4th new driveshaft. New tires and wheels. Car has 1000 miles since complete rebuild.

[XH29N0G]

Do the vibrations change on accelleration vs decelleration vs coasting with clutch pedal in?  What gears are you running?

I had two cases.  In one it was driveline angles and I had to lift the tail of the transmission considerably.  It sounds like you have ruled that out.  I also had another case of vibrations when I went to 4.30 gears.  The driveshaft needed to be balanced better.  The possibility of play is a different issue than I had. Those are three of the suspects.  I spend a lot of time tracking it down for my car and will think some more.  I never did, but almost reached the point of putting a little camera in to see if I could see it happen.

[flyinlow]

Use a GoPRO camera. Mount it so you can film the driveshaft at 60 mph. See if its jumping around.

[Kern Dog]

I just finished a Tremec installation and the car runs along at every speed as smooth as ever. Is your tailshaft tucked up like this?

[XH29N0G]

I just finished a Tremec installation and the car runs along at every speed as smooth as ever. Is your tailshaft tucked up like this?

What Kern Dog says is important and as you are aware he just went thought this with a very nice install.  I also found the tail needed to be really tucked up.  More than my kit allowed.  I had to send my tremec off to silversport to have them notch the housing. I also had to shim the tail of the transmission up from what the kit crossmember gave and I also shimmed my K member. FWIW I found it difficult to measure angles correctly with my phone a phone and had better luck with a magnetic angle finder, but I also verified with physical measurements from the ground and used trigonometry.      

I have a thought I believe the angles depend on things like how the ride height is set and if the tires are bigger in the back. I wonder if some of this could be adjusted out by changing the ride height with adjusting the torsion bar height to raise the tail of the car a little and tilt the nose down a little.  You would need to know that it didn't create any other issues.  I think it will change castor and camber. Could be a stupid idea, but if it changed the vibration, it might point back again at driveline angles.


What are the angles that you measured?

my driveline angle issue did not come in until about 70 mph and changed with load (uphill/downhill/coasting/decellerating/accelerating).  When I had a misbalanced driveshaft it came in about 55 mph.  I do not if that was significant.

Good luck with this.  I know it is a pain in the ass.

[Kern Dog]

I'm sure that a  dude with some chassis experience will be able to clearly define at what point a misalignment would cause trouble.
I had a transmission crossmember in my car that was modified and sat way too low. The car has always had some type of vibration however slight. I just attributed it to old car standards of comfort. This put the header collectors about 3 inches below the floor. This Tremec swap resulted in a higher tail shaft angle than I had before. Now the headers are 2 1/4" from the floor. Zero vibrations. 3/4" difference and this much of a change? I am skeptical of that. I credit the transmission more than the angle.
It gets weirder though.
When I compared my modified 727 crossmember to a stock one with a new mount, there was a difference of 1 1/4"  Would the Charger have had smoother operation had I had a correct drive line angle with the 727?
Maybe. I still think that the tighter tolerances of the Tremec and the fresh U-joints and drive shaft get most of the credit.

[Kern Dog]

Oh, sorry....
I have ZERO slop in the yoke. In fact, I thought it was TOO tight of a fit. I even called the SST tech guys thinking that I had a problem. The man said that it fits tighter than the old style transmissions like the 727.

[XH29N0G]

No offense intended if I am responding to someone who knows more than I do.  Thanks KD for pointing it out.   

[Kern Dog]

With me, I appreciate all responses when someone is trying to help.
I even run some of my problems past the Wife. Sometimes a problem is being "over-thought" and a person with less experience can offer a simple solution that did NOT occur to me.

[ChargerKen]

My actual angles are 2.5°  down on the transmission, 1.5° Up at the pinion, driveshaft is 1.1°

[flyinlow]

With me, I appreciate all responses when someone is trying to help.
I even run some of my problems past the Wife. Sometimes a problem is being "over-thought" and a person with less experience can offer a simple solution that did NOT occur to me.

That's one of the wisest posts I have read on the Web.

[flyinlow]

Once I chased a drive train vibration after installing an OD trans for a month. No luck. Took the fan belts off . Drove briefly to 60MPH. Vibration gone. I had replaced the alternator with a higher amp one over the winter. Because of the weather I did drive it for a while afterwards and forgot about it. Bad alternator out of balance. I and others would have sworn the vibration was drive train.

Probably not your issue, but it's cheap and easy to check.

[ChargerKen]

Ha! That's amazing ! Mine is speed related not RPM.

[ChargerKen]

Ok. Put the car on jack stands. Ran up to road speed with no tires or drums. Same vibration.
I certainly appreciate all input I receive. Would love to road trip this car.