: '99 El Dorado Tranaxle Modulator Location and Replacement

05-26-08, 12:47 PM
I have taken the advice of a former post and purchased the trans modulator for the '99 El Dorado transaxle ($14.00). Now the big question is where exactly it this located on the vehicle (trans) and what is the best, most effective way to replace it? I have been looking and have not been able to locate it yet. Any advice and guidance is greatly appreciated.

05-26-08, 06:06 PM
Renoah, there is no modulator valve on the transmission of a 99 Eldorado, the 4T80E transmission uses a Pressure control solenoid valve, which is located in the sidecase, a 4T60 E transmission like the ones on the older Sevilles and Devilles which use the 4.9 liter motor does have one.

05-26-08, 07:12 PM
I have a '99 El Dorado with 110,000 miles. It has been problem free and maintained. Recently when going 70 mph or greater it will begin to smoke white out of the exhaust. When I drop below 70 this will stop. It does not do this everytime above 70, I will say 50% of the time. The oil is not milky and the coolant does not appear to have signs of oil in it.
I have also noticed lately that I have had to add trans fluid quite often. Recently on a 350 mile trip I crept up above 70 mph and had the cruise set. After approx 45 min I noticed that it began to smoke white. At the same time the "Trans Hot Idle Engine" code 112 indicator came on, this is the one and only time this has came on. I pulled to the side of the highway. When I popped the hood I noticed that it looked like trans fluid had come out of the black tube that comes up on top of the engine that has a silver cap on it. You can move the cap up and down without it coming off (appears to be a relief valve). At this time I also had to add more fluid. I have not seen any indication of any fluids leaking under the car (there is no fluid found on the ground when parked). The "service transmission" indicator code 100 has never came on. The car has been driven 5-7 times since this with no issues. What are your suggestions as to what this could be and what should I do now to prevent a major occurance from happening soon?

05-26-08, 09:48 PM
Replace your Transmission!

You have a major failure! The Trans is getting SOOOOOOOOO hot that the fluid is boiling or burning! It sound like a bigger problem than a 4th gear band slipping. It sound like it is now JUNK!