89 Cadillac Eldorado Transmission O.Drive

Hello All,
Question regarding a 89 Cadillac Eldorado 4.5 V8 FWD, Transmission - 260,000 miles on car, runs great. Last couple of months, I have noticed that it will only shift into O.Drive when the car is cold, sat overnight. It will shift 4 or 5 times into O.Drive no problem. When car warms up, then it will not shift into O.Drive ever again, and I will get a 39 error code. Are there solenoids that I can replace, if so where are they? I’m not sure where to start with this problem?
Thanks Everyone
Todd K

I can tell you that the Allante was plagued with the same transmission and getting them rebuilt properly is very difficult because several of the plastic shift solenoids are simply unavailable…These transmissions were somewhat unique and most transmission shops have learned to avoid them…So before you commit to a repair, be SURE the technician knows exactly what he is dealing with and will stand behind his work…

Thank you for the advice. Figures I would have the “Problem Child” unit & extinct parts. Ugg.
Let’s try another question regarding a 89 Cadillac Fleetwood, same engine 4.5 V8, I would presume the same transmission. Approx180,000 miles. Runs fine, shifts fine, with the exception of; any speed below 60mph no problem at all, all gears shift fine including O.Drive. At 65MPH, you can feel the engine make a very slight movement/vibration, then the Check Engine Light comes on. I know this has something to do with the transmission, but not sure as to what this is or means. Advice is appreciated.

Is the Fleetwood FWD?? Ah, yes it was GM’s “C” body. The Fleetwood Broug, the “D” body was RWD…

here are the transmissions used in the FWD cars


1985–1986 THM440 T4
1987–1989 4T60
1990–1992 4T60E

As you can see, they changed them every 2 years…Perhaps your 4T60 is not the nightmare I think it is…The Allante may have used a variant because of the electronic controls for everything…

These were Dark Years for Cadillac…The power-trains were problematic…The introduction of the Northstar in '92 did not help matters much, except those cars were pretty quick but even MORE fragile than the engines it replaced…

If your Eldo is the same as my Allante, the “Engine Cradle” must be removed from the car (the body is lifted off the engine/transmission unit) before the transmission can be worked on…All of these transmissions are chain-driven from the engine and as the chain wears, it can start flopping around and doing some very strange things…As you can imagine, repairing any of this stuff is very, very expensive because of the labor involved…Getting it done RIGHT is another issue all by itself…

I don’t know that I’d be calling a transmission that’s acting up at 260K miles a “problem child” - though I guess it seems to be for repair.

The 39 is an issue with the torque converter clutch lockup. Typically the only thing that joins the engine rotation to the transmission rotation is fluid inside of the torque converter. However, under certain conditions such as highway speed cruising there is a clutch that will “lock up” and basically make a mechanical connection. It improves fuel economy.

This lockup depends on the operation of a solenoid (TCC solenoid), and it could be that solenoid is acting up once it gets hot. This would not be an uncommon failure mode. If you can find one, I believe it would be located under the side cover of the transmission. However, you might not be able to remove the side cover without dropping the transmission - at least part of the way - out of the car. I’m not sure. You’d have to look into it more.

However, if the fault is electrical it could also be in the wiring outside of the transmission, including something as simple as a bad ground. These things can be checked and verified. If you get a pinout for the transmission connector, and track down the normal resistance specs for the TCC solenoid you can at least check the solenoid’s resistance while its still in the car with nothing but an ohmeter. You’d obviously want to look at it both hot and cold.

One more “however” though, which is that I think I think this code is just triggered by a higher than expected RPM signal. As such it doesn’t tell you whether the problem is electrical or mechanical. The TCC clutch itself could be slipping, or internal wear may make it so that the transmission fluid pressure can’t be maintained well enough to keep the TCC applied. Has this transmission ever been serviced? New filter/fluid?

As for the '89 Fleetwood, its hard to know where to start without a code. But it wouldn’t surprise me if that’s also a TCC issue.

MORE info…The Eldo should fixable. It’s the Allante with it’s TH440-F7 that’s the problem…

GM Automatic Transmission

Cadillac Vehicle Models With Transmission Info.
Model Year Engine Trans Type Transmission
Allante 1987-1990 F7
Allante 1991-1992 4T60
Allante 1993 4T80-E
Cimarron 1982-1988 TH125C
Concours DeVille 1994 - Up 4T80-E
DeVille 1973-1984 TH400
DeVille 1994 - Up 4T60E
Eldorado 1967-1978 TH425
Eldorado 1979-1981 TH325
Eldorado 1982-1985 TH325-4L
Eldorado 1986-1990 TH440-T4/4T60
Eldorado 1991-1992 4T60-E
Eldorado 1993 - Up 4T80-E
Fleetwood - 3 speed RWD 1974-1984 TH400
Fleetwood - 3 speed RWD 1980-1981 TH200C
Fleetwood - 3 speed RWD 1982 TH350
Fleetwood - 4 speed RWD 1981-1989 TH200-4R
Fleetwood - 4 speed RWD 1990-1992 4L60
Fleetwood - 4 speed RWD 1994 - Up 4L60-E
Fleetwood - 4 speed FWD 1984-1990 TH440-T4/4T60
Fleetwood - 4 speed FWD 1991-1993 4T60-E
Seville - 3 speed FWD 1980-1981 TH325
Seville - 4 speed FWD 1982-1985 TH325-4L
Seville - 4 speed FWD 1986-1990 TH440-T4/4T60
Seville - 4 speed FWD 1991-1993 4T60-E
Seville - 4 speed FWD 1993 - Up 4T80-E

Hello All,
Again, Thank you for your replies.
I am not sure what to do first. The obvious & simple thing would be to change fluid/filter. Then I can trace down the wiring harness, make sure there are no broken, cracked wires.
I do have the GM Service Manual for both vehicles, and it does mention the TCC Solinoid through it’s criptic explanations. I will change fluid/filter, but till the weather breaks here in Ohio, I’m not going to do more. I have several Salvage Yards that I frequent. When it does get warmer, I will take a weekend, find a donor car, take the transmission apart and see what I can find. Maybe a better solinoid than what I have.
Normally, with the age/miles my vehicles have, I would not mess with it. Both cars are in excellent shape, ride and drive nicely, and I intend on keeping them. Value wise they are not worth much anymore. I still like them.
PS…The 89Fleetwood 60 Special Edition and 89Eldorado Barritz are both FWD vehicles.