This is my first Lightning and I got it in February of this year. I have looked through several forums and have not found an answer to the issue I am having with my truck.
A little information on the truck. 1993 with 157,000 miles. Stock except for under drive pulleys (done by previous owner), smog pump deleted, and Bassani exhaust system.
Since I have owned it I have replace the spark plugs and wires, distributor cap, ignition coil, upper and lower intake manifold gaskets, oil pan gasket, water pump, rear main seal, fan blade and clutch, belt, all hoses, master cylinder, brake lines, brake pads, changed all transmission fluid (including torque converter), transmission filter, installed larger transmission drain pan with drain plug, changed fuel filter, fuel pressure regulator, MAP sensor, TPS, cleaned throttle body and IAC, changed thermostat, replaced vapor canister solenoid, set timing, rebuilt the A/C system and upgraded the alternator to 130 amp.
I was having some transmission issues with very hard shifting, going into neutral while driving, weird double shifts into each gear and things like that. I checked ECU and found all 3 capacitors were leaking so sent it to ECU Exchange and they repaired and sent it back. Installed it and the transmission was MUCH better. The only two issues I have after the ECU was rebuilt is when the truck shifts into 4th gear, it feels like a "double shift". Two distinct shifts less than a second apart and the other issue is while driving on the interstate over 55 MPH (after everything is warm) the transmission feels like it slightly shifts to lower gear and back again but it is not shifting to 3rd. The RPM drop by 200 RPM and then will go back up. It is not a gradual change, feels like something engages and then disengages. Sometimes it will stay 200 RPM higher for 2 seconds or can stay for 20 seconds. Doesn't seem to matter if I am going up an incline or down a decline. It may not do it for 3-4 miles straight and then wont stop doing it for the next 3-4 miles.
The last time I drove it, it seemed like if I stayed under 55 MPH it didn't happen but I only tried it for a few miles. I have checked the electrical connections at the transmission and everything is very clean and the wires are in great shape. Everything is tight and sealed. I traced the wires up and over the transmission and everything looks good all the way back to the main harness. Fluid level is correct. I also sent the PSOM to Module Mechanics to have it rebuilt and see if that helped but it did not change anything.
Any suggestions on what to check next? I dont know much about how the solenoids work, the valve body or the torque converter clutch but I am hoping someone has some experience with this transmission and can point me in the right direction.
Oh, and I did at the very beginning of everything, and have several times since, pulled the codes and there are no codes now and have never had any that have any relation to the transmission. Only had one for the MAP sensor before I replaced it and the vapor canister solenoid before I replace that.
Any help would be appreciated.
A little information on the truck. 1993 with 157,000 miles. Stock except for under drive pulleys (done by previous owner), smog pump deleted, and Bassani exhaust system.
Since I have owned it I have replace the spark plugs and wires, distributor cap, ignition coil, upper and lower intake manifold gaskets, oil pan gasket, water pump, rear main seal, fan blade and clutch, belt, all hoses, master cylinder, brake lines, brake pads, changed all transmission fluid (including torque converter), transmission filter, installed larger transmission drain pan with drain plug, changed fuel filter, fuel pressure regulator, MAP sensor, TPS, cleaned throttle body and IAC, changed thermostat, replaced vapor canister solenoid, set timing, rebuilt the A/C system and upgraded the alternator to 130 amp.
I was having some transmission issues with very hard shifting, going into neutral while driving, weird double shifts into each gear and things like that. I checked ECU and found all 3 capacitors were leaking so sent it to ECU Exchange and they repaired and sent it back. Installed it and the transmission was MUCH better. The only two issues I have after the ECU was rebuilt is when the truck shifts into 4th gear, it feels like a "double shift". Two distinct shifts less than a second apart and the other issue is while driving on the interstate over 55 MPH (after everything is warm) the transmission feels like it slightly shifts to lower gear and back again but it is not shifting to 3rd. The RPM drop by 200 RPM and then will go back up. It is not a gradual change, feels like something engages and then disengages. Sometimes it will stay 200 RPM higher for 2 seconds or can stay for 20 seconds. Doesn't seem to matter if I am going up an incline or down a decline. It may not do it for 3-4 miles straight and then wont stop doing it for the next 3-4 miles.
The last time I drove it, it seemed like if I stayed under 55 MPH it didn't happen but I only tried it for a few miles. I have checked the electrical connections at the transmission and everything is very clean and the wires are in great shape. Everything is tight and sealed. I traced the wires up and over the transmission and everything looks good all the way back to the main harness. Fluid level is correct. I also sent the PSOM to Module Mechanics to have it rebuilt and see if that helped but it did not change anything.
Any suggestions on what to check next? I dont know much about how the solenoids work, the valve body or the torque converter clutch but I am hoping someone has some experience with this transmission and can point me in the right direction.
Oh, and I did at the very beginning of everything, and have several times since, pulled the codes and there are no codes now and have never had any that have any relation to the transmission. Only had one for the MAP sensor before I replaced it and the vapor canister solenoid before I replace that.
Any help would be appreciated.