For the first time in two weeks,I've had a chance to go over 60mph,and around 60 or so,the rear feels like it's vibrating.I'll re-check the fluid .I did lose a little with a loose fill plug,but I don't think very much,I could be wrong.The rear has been in for two weeks.I'll also check the driveshaft bolts tomorrow as well.Any other ideas?I'm tired and don't feel like thinking.Long day.
Definately check them bolts.
First thing tomorrow,I'm all under that car.
check your slop for the yoke. If the tailshaft bushing is worn, vibration will transfer. If you do have slight up and down play in the yoke,, look at my diy link and in there, tom has a neat trick for installing a new tail shaft bushing. Last i remember, they are very cheap.
heck, it might be as simple as ujoints to.
just to verify it it is/is not the d/s, mark your d/s at the 12 , 3 , 6 and 9 oclock with a marker up near the yoke and back at the rear.
install a hose clamp up near the yoke with the buckle at the 12 position. drive and if vibs go up, locate buckle to the 3 and re test. Move on to the 6 and 9. If vibs still go up, move the clamp to the rear and repeat.
I'll try the clamp method and check everything when it warms up a bit today,and,the sun comes out.I'll post the results.I didn't have ANY vibration problems with the 2.73 rear at all.
I noticed the leak in the diff cover is worse than I thought.I bought a new gasket,Mobil 1 gear oil,and additive.More news as it happens.
I've had vibration issues to some extent since installing the 3.73 TC rear. I've done every trick in the book and I've only been able to minimise the issue.
Things I've done:
1. New Supercoupe driveshaft - shortened, balanced with new u-joints.
2. Installed new TKO output shaft in the Tremec 3550. Bored tailshaft for new bushing and installed new bushing.
3. Did the rotate driveshaft 90 deg. thing 'till I found minimal vibration position - still bad @ 65-70 MPH.
4. Installed new TKO 500 tranny.
5. Installed new carbon fiber driveshaft
6. Re-shimmed rear gears when Eaton E-Locker was installed
7. Axels are new 31 spline units.
There is nothing left to replace with something new - vibration is still there in shifter/miror @ 73 MPH. I've spent $2500 in new parts (mostly for racing) but vibration issue still persists to an extent that it shouldn't with a carbon fiber driveshaft and new TKO & tight rear gears & new u-joints.
Why does everyone think it's the rear?
Hey vinnie you did check it out before you put it in?
I guess I need to PM you again!
How could I check it out before I put it in?I helped the guy pull it out from under his Cougar.Nice car as well.He did top notch work.I know that doesn't necessarily mean anything,but,he used good stuff.Tomorrow before I go to the boneyard and get a replacement hood latch,I'm going to replace the gear lube and cover gasket on the differential.It may just be low on fluid.Maybe.I wanted to do that today,but time didn't allow it.Tomorrow is my last day off til next week,and I have to get a lot done.Deal with the rear,install my stereo (I'm going CRAZY witout tunes !!!),replace my noisy belt tensioner,and a the cs around the house.I'll post my findings.
check your tires
Tires are good.I JUST got the time to change the diff. fluid.I'm getting ready to get my boy from school and I'll see how she does (the Sport).If this didn't fix it,I'll reposition the driveshaft,then the hose clamp method,and so on.One fix at a time so I'll know exactly what the problem is.Thanks guys.
How are your shocks?
Have the rims been checked for roundness?
Are there weights installed on all rims?
Is there any weight (for balancing) at all on your current driveshaft?
The key to solving the problem is the speed issue. If you get no vibrations before or after a certain speed, but can reproduce it regularly at a particular speed, then usually that indicates a rotating shaft imbalance. I had a shimmy on the convertible when I bought it that could be reproduced at 25-32 mph. Before and after those speeds, never an issue. When I had to get my driveshaft shortened due to the longer Lincoln AOD tailshaft, the shop asked me if I'd had a shimmy. I told them, "Yeah, sure did," and he brought out the old driveshaft tube. There were 3 counterweights of different sizes attached to it. He said, "Well, that was your problem." I've never had an issue with the new driveshaft.
And for the record...it is entirely possible that an axle shaft is ever-so-slightly bent. I've seen it happen. Remember, rotating shaft imbalance...
Well,I have yet to test the car.I can't get away from other "stuff" at the moment.It's pretty sad when it takes 2 days or more to find a chance to drive over 65mph.I'll double check the wheel weights.The wheels are great.before the rear swap a couple of weeks ago,no vibrations at any speed.Only after the rear was installed.I'll be checking everything else after I see if the new fluid fixed the problem.