1972 Cadillac Eldorado Transmission

[Bill Young]

Hello, I recently bought a '72 eldo and will be using it as a daily driver. Would anyone suggest what would be best to do to increase the longevity and reliability of the Cars transmission?
Thank You in advance.

[The Tassie Devil(le)]

These transmissions, like the TH400 are virtually indestructible.

The big thing for longevity is Service, and that includes Oil Change and Filter change at the prescribed intervals.

But, seeing as most times, Transmission Services are the last thing on owners minds, and they hardly ever get done, they do last virtually forever.

If you are doing any heavy duty driving/towing, it is adviseable to install an extra oil cooler, as the cooler one can keep the oil, the longer the internal parts will last.

Correct fluid level is a must.

Bruce.

[mgbeda]

Assuming you don't know how long it's been since the last tranny fluid and filter change, I'd say you should change them now.

DON'T have it done at the quicky oil change place.  Most of the time they will not actually open up the transmission, but just pump the oil out of the dipstick hole.  I've also heard they now offer a transmission "flush" at these places that can do more harm than good... something about running the oil though the wrong direction, but I'm not exactly sure.  Make sure to ask if they are changing the filter too.  If they say no, look puzzled, or say "What filter?" don't let them do it.

On my DeVille I've been running an increased depth pan that increases the fluid capacity on the TH400.  I'm not sure if it matters, and unfortunately I don't think they make these for Eldorados (The DeVille TH400 shares a pan with many muscle cars).

Overall these transmissions are pretty tough, especially if you don't do much drag racing.

-mB

[Bill Young]

Thank you Gentleman. I will schedule the transmission fluid replacement and filter replacement with a reputable Garage soon.
Sincerely , Bill Young

[TJ Hopland]

They do make deep pans for the 425 trans, they were made for the GMC RV's that used the same drive line.   I'm not sure if there is more than one company making them or not.  The one I have was kinda mediocre quality wise and was not especially cheap.   It took a lot of fitting and grinding to even get it to fully seat.   Also appears to be a fairly pours casting.  I don't even remember where I got it, it sat on the shelf for a couple years before I finally got around to installing it then the rebuilt motor crapped out so there was more delay before I got around to dealing with the leaking pan.  I tried to contact the place I got it and never got any replies to email or by phone.   

[The Tassie Devil(le)]

I wouldn't be running a deeper pan as the ground clearance will be even less.

Bruce.

[Bill Young]

Right Bruce. I don't plan on replacing the Pan , Where I Live they don't flatten anything out before paving they just pave so there is a lot of up and down. Not a good idea for low clearance.

[bcroe]

Right Bruce. I don't plan on replacing the Pan , Where I Live they don't flatten anything out before paving they just pave so there is a lot of up and down. Not a good idea for low clearance.   

If you are serious about it being reliable, check if its ever been apart.  The rubber seals at this
age get hard or frayed at this age, which can cause a leaking clutch piste seal, a burned up
clutch pack, and poison the rest of the trans.  Every trans I have is that old, and they all have
new "soft" kits in them, only around $30.  Unfortunately if you pay to have it done, the labor
is about the same as an overhaul. 

And I hope the car has a replacement timing chain.  Bruce Roe