gavanm01

Have posted on and off for 19 months on vibration problem with tremec 5 speed. Everythingfrom the driveshaft to new tires (and all the stuff between those components) has been replaced, rebalanced and reblessed by the local parish priest. The rythmic humming at 68 mph and higher and vibration in various parts of the body/steering wheel have been tended to by three good shops. The typical fix will last 100 to 200 miles and then return. Even made it to 130 mph with the latest solution of a 3 inch driveshaft only to have the problem resurface again. I give up; costs too much money to make this work. Want to put the old muncie back in but was thinking of something instead of the 3:08 in the rear end. Someone suggested a 2:73 but sounds too much for taking off in first. Looking for other ideas out there so fourth speed doesn't burn up the engine or gas. Help!

spedaleden

Did you put a Keisler or someone elses kit in?

Did you get a trans and install it your self?

If it was a keisler, I would run it to them in TN. They'll get it right.

b71vette

What pressure plate are you running, not by chance a Centerforce is it? sometimes those counter weights get out of whack, it's odd that it comes and goes, sounds like something is moving around and that came to mind.

72LS1Vette

I'd suggest checking the driveline angles at the trans and the differential to see if something is out of whack. There are some recent threads on driveline angles. I don't remember the specifics offhand but there should be a few degrees of angle for the u-joints to work right and the total shouldn't exceed 7 or 8 degrees from the trans to the diff or you will get vibration.



Rick B.

Retro78

I was also just going to suggest that. They can seem like a driveline related problem and also come and go. If you dont want to spend any more money...just pull the weights off. Centerforce told me directly that the weights dont do anything below 3000 RPM.. and even with weights off the clamping force is still much higher than a stock unit. They also said that the application that gets the most benefit from the weights are rock-crawlers....very low gearing at high RPM's. Wont cost you anything except some time to pull the weights off and try it....assuming you have a CF unit.

I'm Batman

Were your tires ever balanced on a GSP9700 road-force balancer? If not, they haven't been eliminated as an issue.

FB007

He changed trannys and now has a vibration. What does that have to do with tire balancing?

OzzyTom

I am in a similar situation tracking down a vibration at 45~50 mph.
Just as stated here.... a slow rhythmic repetitive vibration.
Always at 45~50 mph, irrespective of what gear it's in.
But if I push the clutch pedal in, or coast in neutral, it disappears at those speeds ???
BUT I also have a vibration at elevated rpm, above 4500 it gets very noisy.

I'm still waiting for a proper response from vendor of trans and clutch and flywheel.

In the meantime, I have checked for clearance issues and found a few trans and bellhousing contact points to body, and have addressed them.
Also found left engine mount was not providing proper isolation... fixed that. Rotated balanced and rotated tyres to eliminate that as an issue.
Re-balanced the tailshaft (at 3500 rpm) which was out, but that did not solve the vibration issues.
Horizontal gearbox alignment is good, vertical alignment could be better, but I have insufficient trans tunnel clearance to improve the angle. Improved slightly by lifting floor using high density rubber strip packed between trans crossmember and floor.
Isolating contact points has attenuated the noise level, but the fundamental vibration is still there.

I now have pulled the gearbox clutch and flywheel out to check everything again....
I have now sent out my flywheel to get checked for correct counterweight.... I have an externally balance motor which was supplied with a flex plate (externally balanced)
The flywheel was supplied by the gearbox vendor, and suspicions regarding the vibration at elevated rpm are pointing at either the flywheel or clutch pressure plate.
I wasn't sure how this could be done without pulling the motor apart...
Apparently the balance shop has several cranks setup for both internally balanced and externally balanced motors.

My flex plate will be attached to the balance machine, and instrumentation will be zeroed. Then my flywheel will be put on, and checked for correct balance. If it's out of spec, it can be drilled accordingly. Hopefully that will overcome my elevated rpm vibration.

It's ironic I guess, we go through all the exercises of researching all our parts, crosschecking with suppliers, asking all the questions, excitement building with the anticipation of all those components providing the ultimate buzz when you get it all together....
.....
but reality sinks in when you end up trying to overcome one bug after another. I could go on and on about some of my electrical woes....
but that's off topic.

I feel for you Gavin, as I'm in the same pickle.
Hopefully I can solve my issues and it may provide some insight for you.

cheers

I'm Batman

Because the source of the vibration might not be the transmission. The tires have been replaced, and the vibration shows up at one speed, not one RPM range. That can indicate a problem with a harmonic vibration in a tire.

You seem to have an issue with me, making snide comments and the like. I really don't care. I used to work for one of the largest manufacturers of alignment and wheel balancing equipment - I have a bit of knowledge on the subject. The guy who designed the GSP9700 was in the cube across the hall from mine - I got to know a bit about harmonic vibrations in tires. Try actually reading the description of the problem before making your pathetic swipes at me.

For the reading comprehension impaired:
In fact, considering the fact that the vibration is only showing up at a certain speed rather than a certain RPM range almost guarantees that the problem ISN'T in the transmission or engine. If it was, it would almost certainly show up at the same RPM range regardless of vehicle speed. I can say with near certainty that the problem is located somewhere behind the tailshaft of the transmission or in one of the tires.

Stroker-427

If I have well understud, te problem (vibration) is related to the speed of the car (+68 mph) and not to the engine speed!

First of all, we must exclude any part that can have asimilar condition of rotation at different speed:
Engine,
Clutch,
Transmission..

and anything before the slip-joke!

The oly parts allways related to the wheel speed at the same manner are:
Wheels
U-joints
Half-shafts
Differential
Driveshaft
related U-joints

The things that was replaced may are the transmission, the driveshaft, the U-joints and the slip-joke..... correct?

At 68 mph with near stock wheels the driveshaft is rotatind nearly at 2650 RPM and an out-of-balance condition will generate a vibration in the range of 45-50 Hz...... very low frequency sound which is able to start all the tipical resonances (harmonics) of the body and of the frame.

My opinion is that the problem should be in the driveshaft area..... or a misalignementin the vertical plane or bad horizontal allignement.

The angle between the slip-joke and the diveshaft must be the same than the angle between the driveshaft and the differential joke.
I other words slip-joke and differential joke must be parallel in both planes.

It is this condition verified?

OzzyTom

In my situation with vibration at 45~50 mph..... I do have a vertical mis-alignment which I am trying to overcome.
It will most likely require placing more shims on the body mounts to raise the body higher on the frame, so as to provide clearance to raise the rear of the gearbox.
I measured angles as best I could, and have 4* down from vertical at the trans, and 2* down at the diff.....
If I understand the info I've read regarding tailshaft alignment, I need to raise my trans through 6* to provide a parallel alignment with the diff. There simply is not enough room to do that at present, so how much misalignment is acceptable? After all, the diff is fixed in position.... it's not like a solid axle car where the angles change as suspension compresses.

Other option I guess might be to raise the diff at the front mount?
Is this feasible? or would I be compounding my problems more?

dohh! maybe I should've stuck with the auto

Stroker-427

So you mean the tranny is downward at the tail and the diff is downward at the joke?


......like a very wide "U" ???

FB007

I have no issue with you. I did not even ask you. He replaced the tires and had them balanced after the fact, and it made no improvement. I believe his issue lies elsewhere, therefore the question.

Stroker-427

One question....

Didi you have some free end-play at te slip-joke?

In other words, it is your slip-joke at the end of the stroke and the drive shaft compressed between the tranny and the differential?

6° is quite a lot..... may your plobem is binding of the u-joint?

68 NJConv 454

I'm going to have to agree with Stroker and Batman.
I have no professional experience in the engineering world but common sense tells me if the vibration is related to speed and not RPM (check this by running thru the gears) then it is, like stated, after the trans tailshaft. If the vibration does happen in 2nd or 3rd gear up to redline under 68 mph then you know its not the engine, trans or clutch.
Therefore, could be...
-as mentioned, driveline angles on the yokes and u-joints
-driveshaft & half shaft balancing
-tire balancing (not all shops do a perfect job) I've taken my gf's PT cruiser to three STS shops and they have yet to do it right. They even put the wrong weights on the wheel. Might just fork out the extra $ and take it to a non-sts shop.
-Are you sure its in the driveline? not suspension or steering? Cars have been known to get squirly or vibrate at a high speed due to loose steering components or front supsension. Make sure the front wheels are balanced correctly too.
-If still nothing, then make sure your cell phone/beeper is not on vibrate and your passenger isn't messing with you or your not hitting those bump strips on the shoulder as you stare at the shifter handle at 68mph.
-Could be anything after the tailshaft then, something in your differential or TA setup/bearings. All of that has to be balanced to eliminate all rotational vibration. Generally they come balanced unless your missing a chunk of metal.
All possibilities.
Good luck.

TopGunn

I had 3:36's iin back of my Muncie and it was a pretty good combination. Still a little steep (high) in 1st but not too bad. I wouldn't want any higher than 3:36 myself, it would really be a dog like you stated. Shifting that combo at 3k with good throttle control I could almost make it feel like an auto.

There have been some threads about driveline vibration being eliminated by cutting the thickness of the rubber mount on the rearend that effectively changes the vertical angle.

Good luck,

Bill

PROSOUTH

I haven't been here in a while guys and I'm not up on the subject of Tremec Transmissions of late. I am resuming my project after a 2 year problem I've been dealing with and you can miss a lot in 2 years.

I have a Tremec TKO for my '80 project and have the center force clutch setup to go into it. so I'm interested in all of the foreseeable problems I may encounter.

I also have a 2003 Dodge Ram 3500 Cummins Truck. Mine runs great and is smooth and sweet as can be, others created such a problem for Dodge that thousands were bought back as Lemons. Dodge went through the same trials and tribulations as you describe in search of the vibration cause. I believe they finally found that the cummins engine was at a harmonic level that conflicted with the tubes the frame was constructed from. I believe they were in the process of applying weights to the frame to cure the problem. I'm not up to date on that either but is an idea of harmonics.

I to agree with the RPM vs MPH vibration theory and have a suggestion that may seem simple. Have you pulled the drive shaft and run it up through the RPM range without the drive shaft in the car to see if it vibrates? If it does it should be an issue with something from the transmission forward and if it doesn't it should be from the front yoke back through the drive train.

Other questions also, did you use a divorced front yoke and is it a correct fit as far as travel and depth? Also check your front yoke to see if it is smooth or has any ridges worn into it, check the rear bushing in the trans for like wear that is caused by incorrect yoke bushing alignment. These conditions will cause vibrations but should be RPM related.Taking the drive shaft out may isolate the vibration or point to the area of problem to address.

My next area of attention would be put it on jack stands and pull the rear wheels then again run it up to the MPH /RPM of vibration using different gears ratios of the transmission, this will eliminate tires and wheels and some suspension issues. I would try to maintain the T-arm at ride height to keep the halfshafts at proper degree.

As a last resort I'd pull the transmission taking care to maintain the engines position in the chassis and again start the engine and run it up to the problem RPM range.

Process of elimination, something should show up or it just wasn't meant to be........

68 NJConv 454

Awsome suggestion Prosouth...as long as you could run it up to speed and be safe.
-I would first remove the driveshaft and run it thru the RPM's and feel for a vibration. The front slip yoke should have no wavey feel to the surface that fits on the bearing and seal.
-If no vibration then i would reinstall the driveshaft and remove the half shafts.
-If no vibration then reinstall the half shafts and remove the wheels with the car on jackstands and trying to get the half shafts to their proper geometry as if the car was on the ground.
-If no vibration then put the wheels back on and if there IS a vibration then you know its the wheels.
-If no vibration with the wheels on and the car in the air then you know its something in the front of the car like steering or suspension vibration that only occurs when the car is up to speed and the air is slamming against it.
BE VERY SAFE WHEN THE CAR IS IN THE AIR AND YOUR RUNNING IT THRU THE RPMS.

PROSOUTH

68 NJConv 454 Awsome suggestion Prosouth...as long as you could run it up to speed and be safe.

Thefront slip yoke should have no wavey feel to the surface that fits on the bearing and seal.

There is a bearing/bushing inside the tailhousing should be attended if the yoke shows wear

-If no vibration then I would reinstall the driveshaft and remove the half shafts.
-If no vibration then reinstall the half shafts and remove the wheels with the car on jackstands and trying to get the half shafts to their proper geometry as if the car was on the ground.

I'd reverse the previous two steps, may save some work , and yes the halfshaft removal is an incremental step of elimination

-If no vibration then put the wheels back on and if there IS a vibration then you know its the wheels. While maintaining halfshaft angles

-If no vibration with the wheels on and the car in the air then you know its something in the front of the car like steering or suspension vibration that only occurs when the car is up to speed and the air is slamming against it.

BE VERY SAFE WHEN THE CAR IS IN THE AIR AND YOUR RUNNING IT THRU THE RPMS.

Hope this gets resolved before I install mine PROSOUTH

I'm Batman

Unless it's already been done, I think checking the tires on a road-force balancer should be the first step. Sometimes vibrations show up when the sidewall is under load. After that, the more radical disassemblies should lead to the problem...but it's always easiest to start with the easiest parts to remove.