tranny/driveline help needed

[rebreath]

some history first...
Bought the car in may.had a bad center bearing,still driveable.drove slowly home from NJ to pittsburgh.did fine until last fiftyish miles,when vibration would not stop.so I had it towed the last bit home.changed center(support)bearing and shortly after both flex joints.seemed to fix all probs.drove to and from maine(i tend towards the 80 mark on the highway),problem free.to and from rochester,no prob.countless trips around the burgh(I love to fish) and surrounding area.again,no prob.had to go to syracuse last week and suddenly there is a problem.
Tooling along at about 75-80 when suddenly vibration similar to center bearing failure occurs.to shoulder and under immediately.all was tight and snug.slight play in driveshaft,but overall snug it seemed.back out on highway again,slower this time(50-60) about ten minutes later noise,only this time accompanied by a rhythmic metallic sound also.to shoulder and under again.all is same.parked car-rented car-to and from syracuse.then back to where car was stuck(wilkes-barre,pa).paid a shop to lift so i could get a better look,here is what three pairs of eyes saw.back left control arm bushing is loose(grab wheel at 3 and 9 and wheel moves about 3/8 inch or so.driveshat seemed solid and snug,output shaft on tranny seemed snug(no play)all mount bolts were wrench checked and were tight.decided to drive her home,drove 45 for about 6 hours and suddenly the thumping is back.shoulder,under,check all the same.back out and 10 mins or so back with metallic sound accompaniment.rent room for night.wake up next day,out to car,start her up,drive a bit.no noises.back to highway and make it back to pittsburgh without further event.any thoughts?what does the intermittance indicate?I have not had the car back up to any real speed since it happened last week.could the initial drive from jersey with a bad bearing have done lasting damage to something?I did not exceed 45 the whole way.It did not vibrate the whole time,only when slowing or going over 45mph.several thousand miles since then without any probs.I am gonna pull the shaft and have it checked at driveshaft shop,pondering chasing a good used tranny down if needed (hope not).thanks for your insights....

[Stevo]

I wonder if its possable the PO had the drive shaft out for some reason and separated it without marking it and just stuck it back together. Although they might be factory marked by 84.

You shouldn't be able to feel any for and aft "play' in the drive shaft.

[rebreath]

Originally Posted by Stevo

I wonder if its passable the PO had the drive shaft out for some reason and separated it without marking it and just stuck it back together. Although they might be factory marked by 84.

You shouldn't be able to feel any for and aft "play' in the drive shaft.

so does that mean that any play is an indicator...
also driveshaft seems to be in great condition.not a speck of rust.
what marks should be there?I did not see any marks at all

[Stevo]

To clarify, the "big' nut should be tight enough that you don't feel any play there.

These drive shafts need to be reassembled the way they were taken apart at the spines. My early W123s were not marked but I thought the later ones were. I accidentally separated one once and had too get another drive shaft.

Do a search, there should be plenty about that.

[rebreath]

Originally Posted by Stevo

To clarify, the "big' nut should be tight enough that you don't feel any play there.

These drive shafts need to be reassembled the way they were taken apart at the spines. My early W123s were not marked but I thought the later ones were. I accidentally separated one once and had too get another drive shaft.

Do a search, there should be plenty about that.

Lets assume for the moment that it has been reassembled "out of line" of the unseen marks....is this fixable w/o replacement?

[Stevo]

Originally Posted by rebreath

Lets assume for the moment that it has been reassembled "out of line" of the unseen marks....is this fixable w/o replacement?

I replaced mine because I didn't want to put it back together and have to do it again. There have been elaborate devices cleverly designed to be build a home to re balance the d/s but I wasn't up for that. The other option was sending it off to Portland Or where theres a good shop. Check for a qualified shop in your area, I may have the Portland shop #.

[Brian Carlton]

Originally Posted by rebreath

Lets assume for the moment that it has been reassembled "out of line" of the unseen marks....is this fixable w/o replacement?

That's not your issue. If it was assembled improperly, you'd have a slight buzzing vibration, at all times, that gets worse at higher speeds .........nothing like your current, intermittent symptoms.

What's the deal with the trailing arm bushings? Have you replaced those? It sounds like the entire wheel is free to occillate around the vertical axis by 3/8". I think you'll need to take care of this situation first.........if simply to rule it out.

I've got difficulty accepting another center bearing failure in such a short period of time........

[Stevo]

Originally Posted by Brian Carlton

I've got difficulty accepting another center bearing failure in such a short period of time........

You dont think a mis matched D/S could have caused this, vibration from that causing a bigger problem wrong track? seems a little odd.

[Brian Carlton]

Originally Posted by Stevo

You dont think a mis matched D/S could have caused this, vibration from that causing a bigger problem wrong track? seems a little odd.

It would have to be a severe vibration to trash the bearing in 10K. If it was that severe, you'd know it immediately.

[rebreath]

Originally Posted by Brian Carlton

That's not your issue. If it was assembled improperly, you'd have a slight buzzing vibration, at all times, that gets worse at higher speeds .........nothing like your current, intermittent symptoms.

What's the deal with the trailing arm bushings? Have you replaced those? It sounds like the entire wheel is free to occillate around the vertical axis by 3/8". I think you'll need to take care of this situation first.........if simply to rule it out.

I've got difficulty accepting another center bearing failure in such a short period of time........

gonna fix that as well.cant do that one myself though.so gotta take to an indy.noise always seemed to be coming from slightly behind and below me.why after driving for several hours only?why does it go away after stopping and starting(not the engine)?
Do you(brian) or anyone else for that matter think that having driveshaft checked at a shop would be unnecessary?aside from that control arm,what else could I check?tranny maybe?I am stuck....for the moment!

[Mercury]

Here is a picture of the index marks on my 1984 300d Unbalanced drivetrain?. With any luck, you can see the shop man page "Removal and installation of propeller shaft" here http://www.thesupper.net/kbl/41-050.pdf
In it you can see other indexing marks for earlier vehicles. (PM me if it does not show up)
Doubt that this is your issue, but you asked for the info. Good luck.

[Brian Carlton]

Originally Posted by rebreath

gonna fix that as well.cant do that one myself though.so gotta take to an indy.noise always seemed to be coming from slightly behind and below me.why after driving for several hours only?why does it go away after stopping and starting(not the engine)?
Do you(brian) or anyone else for that matter think that having driveshaft checked at a shop would be unnecessary?aside from that control arm,what else could I check?tranny maybe?I am stuck....for the moment!

I'm doubtful that the alignment of the two driveshaft halves is the culprit. Whether the center bearing has headed south is the real question........and.........why only 10K later.........improper installation.........poor quality bearing???

But, I'd get those trailing arm bushings fixed first. Strange vibrations are difficult to pinpoint, and, when you've got an obvious source of problems, why look elsewhere until that source is fixed?

[JimmyL]

Due to what you stated as the location of the vibration as you feel it, this is probably not the issue, but did you take a good look at both of your rear axle shafts?
Just a thought........

[rebreath]

she is art the shop now.since I am unable to do control arm bushings myself,I will wait and hope that they find nothing major.until the details are available, happy dieseling....

[Stevo]

Hay Thanks for the update, let us know how it is.