Transmission Drive Chain for 68 Eldorado

Forgiven1989 · January 26, 2013, 11:52:11 AM

Does anyone know where I can buy a new transmission drive chain for a 68 Eldorado? Thanks.

TJ Hopland · January 26, 2013, 02:41:55 PM

I have had those transmissions worked on before and never needed a chain. I wonder if its a rare to fail part that may be a little difficult to find a new replacement for? I don't ever recall hearing about one needing to be replaced before. I suspect it would be the same for the 66-78 toros as well as the 73-78 GMC motorhomes. If anyone was going to wear out one of those chains I bet it would be the GMC folks so I would try looking at some of their sites and sources.

Forgiven1989 · January 26, 2013, 09:03:49 PM

I have tried several sources. I was told that the chains are not made anymore. Thanks.

The Tassie Devil(le) · January 26, 2013, 09:27:51 PM

Probably because they never need replacing. I heard years ago that these chains were so over-designed and over-built, that they were almost guaranteed for life.

Has anyone ever heard of one of these Morse Chains requiring replacing?

Bruce.

Dave Shepherd · January 27, 2013, 10:11:02 AM

Looks like everone is hinting at what is wrong with the old one , working at Cadillac for 25 years from 62-87, never knew of one failing.

Forgiven1989 · January 27, 2013, 01:36:31 PM

Well, someone is buying them. I checked with several suppliers and none of them had any left and said that they could not get any more. My 68 Eldorado has a lot of play in the drivetrain. You can feel it when you excelerate and decelerate. Years ago I owned a high mileage 71 Toronado. The chain was so loose in it that it accually slipped past the sprocket if you excelerated too hard. I just want to have one in case I need it. Thanks.

Dave Shepherd · January 27, 2013, 05:31:07 PM

Make sure the rubbler coupling on the axle shaft is not causing this.

Forgiven1989 · January 27, 2013, 06:23:47 PM

I just had both CV axle joints replaced. Would this take care of that? Thanks.

TJ Hopland · January 27, 2013, 06:35:15 PM

If it still had a damper in a shaft replacing them would have solved it since no one has made shafts with dampers for a long time.

How are the motor and trans mounts? I can't remember if it was my 73 or an 80 I was pulling the engine out of but one of them the trans mount had completely disinterested. The motor mounts on the earlier cars are the fairly typical design that cant move much even if the rubber is gone but I think the trans did leave some room to move.

Forgiven1989 · January 27, 2013, 08:33:13 PM

I just had the front motor mount revulcanized by Steele Rubber. The transmission mounts are both OK. Thanks.

Glen · January 28, 2013, 12:40:13 AM

How was your experience with getting your engine mount revulcanized? I need to do my spare.

Thanks

TJ Hopland · January 28, 2013, 09:48:56 AM

68-70 mounts must be different than the 71-78? I was able to buy new ones a couple years ago for mine but it would not be a surprise that they design changed with the other body changes for the later cars.

Forgiven1989 · January 28, 2013, 09:41:33 PM

Glen, The revulcanized motor mount turned out great. It looks like a new one.

Glen · January 29, 2013, 01:08:21 AM

Thanks Dave, Iâ€™ll send mine out soon.

TJ, yes the â€™67 â€" â€™70 Eldorado engine mounts are different. There is one large one in front below the harmonic balancer. There are two smaller ones on the transmission.

TJ Hopland · January 29, 2013, 09:03:18 AM

Interesting that they are different and also interesting that it sounds like the way the 79-85 E's were too.

Anyone know if the 66-70 Toro used the same mount? Or did those perhaps use the the 71-78 style?

Aaron Hudacky · January 29, 2013, 11:06:02 AM

Dave,

When you had the CV joints replaced, were they done on both left and right axles? I'm not sure if the joints can be done without replacing the axle, but if they were, you could still have the damper in the original axle. My 70 Eldorado had the original right side drive axle when I bought it and the damper was shot, making the drive train clunk and feel very sloppy. I replaced the right axle/joint assembly and it completely eliminated the clunk and slack. The left side had already been replaced. From what I've read, only the right side axle had the damper.

Aaron

Dave Shepherd · January 29, 2013, 11:26:39 AM

Lots of intersting info, but in the final frame what is actually wrong with the car? Diagnose 1st, fix 2cnd.

The Tassie Devil(le) · January 29, 2013, 05:22:20 PM

Isn't the "Damper" just a simple Harmonic Balancer? Or is the Right Shaft actually two pieces, joined in the middle of the damper?

I don't have a spare axle to cut up to satisfy my curiosity.

Bruce.

Forgiven1989 · January 29, 2013, 06:38:32 PM

Aaron, I had both CV axle joints replaced. There is still lots of play in the drivetrain especially when you play with the gas peddle. I also at times have a transmission shutter from 1st to 2nd gear. Dave Sheppard, I have taken this car to two different shops. They are both telling me that they are not sure what is causing the play in the drivetrain. One said that it could be that the big nut in the differential could be loose. I sometimes feel like the big nut for buying a car with so many problems. But what can you expect with a 45 year old car? Dave

Glen · January 30, 2013, 01:38:38 AM

The CV joints can be changed without replacing the axels.

In the attached picture from the shop manual you can see the damper on the axel. The axel is a two piece and they are connected in the damper with a rubber piece. I have heard of them breaking completely and the engine side spinning in the damper with no movement at the wheel. If that happens you also lose the locking effect of putting the transmission in park.

When they get that loose they can also wobble causing vibration.

I also see a problem in the photo. The toe-in adjustment should be in the ears up position because it can in some situations hit the sway bar interfering with steering.

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Transmission Drive Chain for 68 Eldorado