Author Topic: 1969 eldorado transmission shudder? (Read 3844 times)

dirtycustom40 · « **on:** December 11, 2012, 08:12:16 PM »

I recently installed new axles,bearings,idler arm and front shocks on my eldorado.I had a shake or shudder at speeds over 50mph that would come and go.It would last about 10 seconds and then go away,sometimes for quite awhile.I put new tires on the car last week but never got a chance to drive the car on the highway to see if all this work took care of it.I made the mistake of assuming it did.
I just came back from a 6 day trip to california and this shudder was still there.It seems the worst at between 70 and 75 mph and is almost non-existant at 80mph.All the rims are straight and tires are balanced properly and front end overall is tight.The steering wheel does not shake at all.Transmission shifts fine and there is no noise at all.It doesnt matter if the road is smooth or bumpy,straight away or a curve.Accelerating or decelerating doesnt matter either.It does this when it wants to and stops when it wants to.Its kind of weird.I had not trouble whatsoever in almost 3000 miles of driving.After several miles on the highway i determined the shudder was in the center of the car like the engine and trans were vibrating from side to side.Just looking under the hood i saw nothing visible but havent looked underneath yet.All that comes to mind right now is engine and trans mounts could be deteriorated.Car now has 76000 original miles.Has anyone had the same experience?This does not feel steering related at all to me.

TJ Hopland · « **Reply #1 on:** December 11, 2012, 09:52:32 PM »

My rambling story about my Eldorado and its vibration:

You are describing what I dealt with on with my car (the 73) for the last 15 years. Over that time I replaced the tires 4 times and a few rims when a shop told be they were bent. Done bearings, shocks, brakes, cv axles, ball joints, complete different engine and transmission. Even changed that short shaft and bearing under the engine. Always thought there was a slight improvement but it never seemed to last so I wonder if it was just me hoping it was better after spending money. It actually got to the point that with the vibration and other issues I just really was not enjoying the car anymore. I even thought about not getting the car out of storage this season. I did end up getting it out late in the season and long story short after 2 sudden catastrophic tire failures in 2 days I ended up with 4 new tires. Car runs smooth and straight and I am really looking forward to driving it and fixing a few more things next season.

There were times driving over the whole period where it was nice and smooth so I would literally just keep driving even if I drove right past my destination because I just wanted to enjoy it being smooth which usually did not last. It seemed that I would hit a slight curve and the vibration would be back. Sometimes it was so bad the keys on my key chain in the ignition would rattle.

When I got the car it had old bias ply tires on it and had been sitting, you can imagine how it drove with those. I swapped those out for some decent looking unknown age radials. If I recall correctly they were something like a Sears brand and looked like they hardly had any miles on them. I had the vibration with those tires so I had them balanced and new valve stems put on. I fixed a bunch of other things on the car and was driving it quite a bit and the vibration was bothering me. Shop said it had to be the tires so I started saving up for new ones. Got Goodyear Ragatas. Vibration still there. Shop said it was chassis stuff so I started saving and as I could afford it got that stuff replaced. Still had vibration. Many years, miles, and other repairs pass. Vibration is so bad can hardly drive on the highway. Take it to a tire shop and find the tread on one of the tires is got a zig zag thing going on. Not that many miles but old enough that I just decide to replace them but feeling cheap and not having a ton of cash I just replaced 2, this time with Regatta2's. Another couple years pass and more issues to deal with including my new rebuilt engine seizing up. Get to the point where the vibration is a big issue again and a shop tells me all 4 tires are junk. Found a shop that advertises with the local club and they actually have the correct CAX weights they improve things slightly but tell me all 4 are junk. All they can get me are tires from the vintage dealers which are not cheap so I sort of give up again and that brings us to this year. 4 new Mastercraft tires from my local Fleet and Farm store (Mills Fleet Farm for those in my area) installed by a bunch of 'kids' working the Saturday shift and its like a new car. They store by my house did not have all 4 tires or the CAX weights so I ended up driving to a sister store for the 4th tire and found they had the CAX weights. Had the local shop just put regular weights on and ran without the caps till I could get to the other place with the weights it ran fine but it seemed even better after I had the 2nd shop re do them with the right weights and it felt even better.

dirtycustom40 · « **Reply #2 on:** December 11, 2012, 10:55:12 PM »

It does get irritating with that vibration.I also did replace lower ball joints.The weights you are talking about i have never heard of but i will ask the firestone dealer about them where i got the tires.I ended up going with hankook brand tires.I asked a few guys around the shop and they all said they were a good tire.I had them installed the day before i left.Ive had a few of these eldorados but havent ever had this vibration with any of them.Ill get under it hopefully this weekend and see what i can find.

Glen · « **Reply #3 on:** December 12, 2012, 12:22:45 AM »

One source of vibration on these cars is the damper on the right drive axle. The way to check that is to put the front on jack stands. Caution: This is dangerous. Take precautions like blocking the rear wheels. With the engine running at idle the trans in gear watch the right axle. If it wobbles as it turns it is bad. This could apply to the left axle too as a clueless mechanic working on the front suspension could bend either axle. If both axles are bent it could explain the rise and fall of the vibrations as the axles add to or cancel the vibration.

TJ Hopland · « **Reply #4 on:** December 12, 2012, 12:42:21 AM »

The CAX weights are like normal clamp on weights except the clamp part is extended to allow room for the hubcap. Regular weights get in the way of the hubcaps. This style weights were only used in the 70's on some Cadillacs and Lincolns so they are pretty rare now days and apparently no one is making them now due to low demand and that many states don't allow lead anymore. I had mine done just using weights on the inside and that was terrible. Before I found the proper weights I was going to have them try the stick on weights they use on modern aluminum wheels. Some people have said the stick on ones would not work but I am not sure why.

dirtycustom40 · « **Reply #5 on:** December 12, 2012, 08:49:36 AM »

I going to get the car up to another shop here in town that has a different kind of lift than we do at work.They can raise the car by the suspension so its on its own weight while tires spin and hopefully we can see something.TJ if i can pinpoint this problem ill let you know.I wont give up till i find and correct this.

LeRoy DeVol · « **Reply #6 on:** December 18, 2012, 06:17:19 PM »

I bought a new 1967 Camaro in LA & from the get go had a bad vibration from the left rear of the car. I took the car to the dealer & they sent me to a tire shop. They balanced the tire, checked for a bent rim, & checked the runout on the tire. When they got done the car still vibrated the same. I went back & they installed a new tire, vibration still there. Went back a third time & they installed another tire. The vibration was still there. I had been silent thru the whole problem, but asked them to do something different. I asked them to install my spare tire in place of the one that was giving trouble. Guess what!! the problem went away. I asked the dealer to give me a new wheel & they refused. Then the dealers wondered why everybody started buying Japanese cars. I worked for Chevrolet for 2 years in 1965 & 1966 and there warrantee was terrible. The American cars have gotten much better since then, but other then the older Cadillacs i only buy Toyotas now. Even when i worked for Chevrolet i had other warrantee problems that i can't talk about now. The one thing i learned is not to take anything for Granted.

Lee DeVol

936CD69 · « **Reply #7 on:** December 18, 2012, 07:12:48 PM »

One other rotating assembly everyone overlooks is the brake drums, which are balanced at the factory. I've seen several "unfixable" vibrations cured when we put the drums on a balancer and watched them wobble!

bcroe · « **Reply #8 on:** December 18, 2012, 08:03:58 PM »

With lots of spare parts, my answer is just swap a different wheel & tire and see what
happens. No change, probably put things back and do the same on the other side. If
that doesn't find anything, change out EVERYTHING that turns on one corner, again
continue to the other side as needed. Most common problem is tires, next rims, then
maybe a bent axle or brake drum/disc. Locating the issue is a lot harder than a fix.
good luck, Bruce Roe

Gene Beaird · « **Reply #9 on:** December 19, 2012, 11:39:39 AM »

Quote from: TJ Hopland on December 12, 2012, 12:42:21 AM

The CAX weights are like normal clamp on weights except the clamp part is extended to allow room for the hubcap. Regular weights get in the way of the hubcaps. This style weights were only used in the 70's on some Cadillacs and Lincolns so they are pretty rare now days and apparently no one is making them now due to low demand and that many states don't allow lead anymore. I had mine done just using weights on the inside and that was terrible. Before I found the proper weights I was going to have them try the stick on weights they use on modern aluminum wheels. Some people have said the stick on ones would not work but I am not sure why.

TJ, the only issue I can see with the tape weights is if you have enough room between the wheel and drum/disc. You'll need about 1/4" to 3/8" space between the two. You'll need to clean the wheels of all dirt/grease rust and have decent paint on that part of the wheel so they stay stuck. Cover them with duct tape, if necessary.

I've used these weights on steel wheels and have had no problems. Weight is weight. I don't see how it would be a bad idea either.

As for the OP 'shudder' issue, does the shudder happen when the engine upshifts, or when you apply the accelerator? Our 79 Seville is in need of a transmission rebuild, as it will shudder going into second gear, and attempting to accelerate when in high gear. I'm suspecting the seals in the 2nd and high gear clutch drums are leaking.

If you have shudder when accelerating, or when the transmission shifts, I'd suspect the transmission, especially if the shudder goes away when you let off the gas. Otherwise, I'd start looking at the drive axles and suspension as others have suggested.

dirtycustom40 · « **Reply #10 on:** December 19, 2012, 07:24:45 PM »

Thankyou far all the recent posts it is all good information.The transmission goes into gear and shifts fine.This vibration does matter if i am accelorating or de-celerating.Smooth or bumpy road doesnt matter and neither do turns or straightaways.It comes and goes when it wants.It lasts for about 10 seconds then stops.It could go away for several minutes and then come back and only last a second or two.Please refer to very first post for more symptoms.I do have the spare rim which i dont think has ever even been on the car.It wouldnt hurt to swap it out though i cant tell where this vibration is coming from.It feels like it is right in the center of the car in front of the firewall but its very hard to pin point when im driving.I havent had time to do anything since returning from my trip.I never thought about the brake drums which i will pull and have them checked hopefully this weekend or next.I dont get much free time.I honestly cant say its the trans,a rim,a drum or anything else.I do know it hasnt improved since new,axles,bearings,idler arm,shocks,lower ball joints and tires.The steering wheel does not shake when this happens and never did and i dont feel anything abnormal in brake pedal.I do need to get it up off the ground and watch everything as its spinning.Thanks again guys your advice is greatly appreciated.I havent ever run across anything like this before where the problem wasnt obvious or quickly located.

Forgiven1989 · « **Reply #11 on:** December 19, 2012, 09:48:35 PM »

I have a 68 Eldorado that has a transmission shutter mostly when it is cold. It only happens going from 1st gear to 2nd. While it is shuttering you can manually shift it into low and it quits ever time. The transmission was rebuilt about 6 years ago with only about 4000 since then. Does anyone have any ideas on this one? Thanks.

Glen · « **Reply #12 on:** December 19, 2012, 11:58:17 PM »

Dave,

Did your trans have the shudder right after the overhaul? I seem to remember the clutch plates for the 68 are different in number than the 69 and later. I rebuilt the transmission in my 68 ELDO. When I took it apart I counted the clutch plates and found a different number (one too many?) than what the rebuild instructions said should be in a 68. I put in the correct number for a 68. It has since always had a shudder when shifting. I later found out the transmission is a 69, not a 68. I have a spare transmission I will rebuild and install.

dirtycustom40 · « **Reply #13 on:** December 21, 2012, 07:46:09 PM »

Got a chance at lunch today to get the car up on the lift and let it run in gear on its own weight and everything spun true.Pitman arm has just a little slack and right rear bearing has just a hair of play.Im going to replace pitman arm in a couple weeks,take it on the highway and see how it does.The bearing will get done after that.All drive train mounts look good as well.We ran motor up to 75 mph and of course it didnt vibrate.After wheel bearing ill do brakes all around just so i know their done.This is the last car i ever plan to buy and the only car i have so ill chip away at it one part at a time till i solve the problem.I dont have another long trip planned till nevada in april so ive got some time to sort it out.

bcroe · « **Reply #14 on:** December 21, 2012, 10:43:16 PM »

The original transmissions have a wavey steel plate next to the clutch piston.
I suppose the wavey plate cushions the shift. The rebuild kits never have a
wavey plate, they suggest using another flat plate. I expect GM knew what
they were doing with the wavey plate, and I always put it back. What is
in your transmission?

Sounds like next part to swap is the trans, easier said than done for most.

Bruce Roe

dirtycustom40 · « **Reply #15 on:** January 13, 2013, 07:20:26 AM »

Well after inspecting everything i could think of on the car and finding nothing out of sorts at all i ordered a box of the cax weights from all tire supply in houston texas.I had tires re balanced over new years weekend but didnt get a chance to really take it anywhere to drive at highway speed till friday and was able to drive at 65 mph and ride was smooth.So far so good.Im going to hit the express way later today and try it at 75 +.If it remains smooth as it should the problem was not having the correct weights.

TJ Hopland · « **Reply #16 on:** January 13, 2013, 05:44:39 PM »

I will be watching to see the results after the next test but that seems to match my experience. It does not really make that much sense but who knows maybe they made those weights that way for a reason other than the hubcap.

Mike Josephic CLC #3877 · « **Reply #17 on:** January 13, 2013, 06:08:41 PM »

I had this same problem with my '73 when it was new. These cars, for whatever reason, are
very sensitive to what's called "radial walk" caused by poor quality radial tires. The car was
ordered with factory radials, which were an option in '73. The quality of radials made then was
spotty at best.

After my original Uniroyal tires wore out I replaced them with Sears tires (made by Michelin)
in 1976 and that's when the vibration started. It was so bad that the steering wheel had a
noticable "side-to-side" movement and the whole front end would vibrate. These tires were
terrible and I took them off a few months later.

Replaced them with Dunlops later that year and the problem went away. The persent tire is
now a Firestone P235R-15 and those have been great. However, they are about ten years old
and Firestone (as most other manufactureres) no longer make that size and whitewall width.

I really dread trying to find a suitable replacement.

Mike

RobW · « **Reply #18 on:** January 13, 2013, 08:12:09 PM »

Mike
I think the American Classics use the old Firestone molds.

dirtycustom40 · « **Reply #19 on:** January 13, 2013, 09:18:34 PM »

Had too much to do today at my folks house so didnt get on expressway.Before tires were re balanced with cax weights there were no weights on outside of rim and i imagine compensating for the brass valve stems does seem necessary.The last time i had one of these was over 20 years ago and never gave weights any thought at all.Looks like its gonna be another 60 hour week so ill have to try for next weekend to get it out on the highway between albuquerque and santa fe.I will post results and hopefully this will help anyone experiencing the same problem.