: Possibly transmission or electronics

05-27-13, 12:15 AM
Hello my father has a 1995 Cadillac eldarado 2 door. Northstar 32valve V8. 116,000 miles .

He had drove home and it was working absolutely fine when he parked it , the next day he backed out of the driveway and put it in (D) and idled it to the mailbox approx 300' . Then turned right and proceeded down the hill somewhat coasting ,then slight acceleration to go up the next hill and when the engine Rpm's caught up with the ground speed it continued on down the road in (D) . He assumed it was in (D) only because the selector was in (D) . He has driven it 3 trips at approx 60 miles round trip and it shifts through first,second,third just fine but never goes into (OD) travels at approx 40mph without over winding the engine . There has been No indicator lights or any signs of damage. I would greatly appreciate any help with a possible causes for it not shifting into overdrive . Possible fuses or sylinoids that can cause this and their location . Him and my mom have always wanted a caddy and I just hate for them to not be able to enjoy it . So I thankyou all now for any help you possibly can lend . :)

05-30-13, 08:27 AM
The transmission is a 4-speed with TCC - Torque Converter Clutch - which is supposed to engage at light to moderate road loads above ~43 mph.

3rd gear is the 1.00:1 gear; 4th is a 0.68:1 gear - OD. The TCC removes the last 300 or so rpm of slip between the converter stator and rotor - it's a fuel savings feature.

Drive the car normally in D - you should feel it start in 1, then 3 shifts up to 4th above 40 or so (load/power dependent).

There are 3 shift solenoids - 1-2, 2-3, and TCC engagement. The 3>4 shift is speed/load/power/fluid pressure dependent.

Has the transmission ever had a GM dealership fluid exchange service performed ? (Not to say that will help anything - just a maintenance feeler)

A diagram of the transmission sensors and switches in my albums.

EDIT: PM question - ???Albums ??? Click a member's username and look at their profile. Albums and such in the left column. If an album is kept current, it (they) can be accessed through the Community tab up ^^^ there.

05-30-13, 11:13 AM
Thankyou very much , I will ask my father today these ?'s and let you know . Again thankyou

05-30-13, 12:28 PM
I spoke to him and he hasn't had the car very long and hasn't had the service performed and haa no knowledge of one being performed prior to him purchacing the car .