You could have bad motor mounts. They are poor and fail often. With the raising and lowering the transmission to gain access to the bell housing bolts and for realignment when installing the motor mounts are tortured. With the hood open push the brake hard and push the gas with the trans in drive while watching the motor. If it looks like the motor is going to raise up out of the engine compartment before you start spinning the tires you have broken mounts. Or your harmonic balancer could have spun, but that shouldn't be worse in reverse.

 

well took it back to the shop and he replaced some solenoid for the hard shifting after highway miles. after he had it for 2 weeks it still does everything I said in this thread. nothing has changed. also what is your guys 4.3s rpm running at 55mph. mine is 1900-2000 2100 at 60

 

ok guys took it back to the shop again and he road in it with me when it was shifting hard. he hooked up his scan tool. for some reason the computer is NOT commanding lockup. and the scan tool doesn't show anything out of whack. when it doesn't command lockup line pressure is sent to max. the computer is expecting a certain line pressure number but its getting a different one. or something like that he told me. the only thing the scan tool shows is that the TPS is "out of range". but no codes . no engine light. and when tested with scan tool the tps acts normal. shows .8% when throttle closed. not sure if that's right or not.

 

Tps effects line pressure. Helps vcm estimate torque. Tranny increases line pressure to prevent slips during shifts when more torque is being used. If the valve body on the tranny wasn't gone through and had the worn valve chambers rebored and new oversized valves put in the tranny will also pick up the leakage and compensate by jacking up line pressure to prevent clutch pack failure. The TCC valve "torque converter clutch lock up apply feel valve" is a common culprit. This is one of the must fix valves on any rebuild. A phantom miss fire may also be appearing and cause the vcm to prevent torque converter from locking up. The vcm thinks you need more torque due to a poor running engine and kicks out lock up. A crankshaft position relearn procedure can often cure this if your engine is intact running smoothly. High line pressure is caused by leakage in the trans or the vcms interepretation of all sensor data. If tps data was out of sack I'd change it. If the shop certified this all blame will be put on that. Fix that IF its not working. If it is and there are no codes on the engine have the relearn procedure done if problem persists take it back to the shop and be more persistent. If all was fine before I sure would suspect tranny shop did an incomplete job. It is possible your other problems were present before and contributed to trans failure. The torque converted not working properly because of bad cm data causes heat and heat in excess destroys transsmisions.

 

Spell checker killed that last post. Lol.

 

so should I replace the tps sensor or leave it since its working. should I try unplugging it and see if it shifts better or what. the mechanics 3000 buck scan tool is saying the tps out of range when he is scanning the transmission, lookin at line pressure, rpm slippage, tranny temp, ect.... but no engine light and no codes come up for the tps. I still haven't checked voltage at the connector yet. will today if I have time. I don't know what to do and the tranny mechanic doesn't know what to do. right off the highway it hits 2nd and 3rd so hard you almost get whip lash. drove it all around today in town and no problems. its only when you get on the highway for about 10min then get into town it shifts hard after stop lights. my warranty is running out need to get it fixed asap.

 

why is the warranty only being extended as
"best effort"? I would ask that they keep the truck and give it to the assigned mechanic assigned to the tranny to drive home and get a courtesy car from them. So what is their suggestion if they can't fix it? The customer service seems to be lacking, almost like the guy test driving it doesn't have the power to request the tranny to come out again and be re-investigated.


I've had a friend take the tranny back three times once, on the third time the valve body had a small crack in a vein. impossible to see... go figure...

 

so I went and checked the voltages from the tps connector and its all reading good. 5v reference, signal wire, and ground all good. also good sweep from .70 volts to 4.60v. remind you its a new sensor. about 2 years old. vibrations still there as well. so does anybody have any idea on what to check next? also the mechanic said he would check into the case relearn procedure in a few days.

 

well its been awhile now and both problems still here. mechanic says its not the transmission. the computer is commanding the highline pressure. and he pretty much said that a crack in the valve body is a stupid idea and he said I don't know who told you that. wow. also the vibration he said is not the transmission either. but it started right when I got into it at the shop to bring it home. also no lockup at all on the highway. rpms at 2000-2100 at 55mph


so far to fix the vibration since the pro told me it wasn't in the tranny, I have put in new fuel pump, injectors, regulator, fuel filter, plugs, wires, cap, and rotor, tps sensor, cleaned entire top plenum until sparkly clean inside, also did valve cover gaskets.


the idle doesn't seem to fluctuate anymore. the rpm needle stays steady. nice and smooth. but still a vibration in the steering wheel and seat at idle not moving.


he also said he could put in a transmission line regulator to regulate the line pressure. but that would only mask the real problem and cause the tranny to fail sooner, right???


also haven't done the case relearn procedure yet. but will it work on an old 95 with obd1.5 and the ecm on the fender well?


Im going back to the shop this Monday to have him disconnect the torque converter and prove to me that the vibration is not in the tranny.


any other ideas guys? im at a total loss right now.

 

Bottom line is… No TCC apply the shop needs to fix it. I am a transmission rebuilder and no TCC will cause the computer to raise line pressure. It will command HI-Capacity mode to protect itself from failure. TPS and MAP are the two main inputs from the motor to the ECM for pressure rise. TPS should give a sweep from .5-4.5V without a drop out. MAP should give a similar reading depending on how it is looked at. A good map sensor will read .5 under hard decal and 3.8v (might be backwards, its been awhile) under hard accel. But if the computer sees either as out of spec you should get a code. Is this a OBD I or OBD II vehicle? The rebuilder himself should be freakin’ out because no TCC is a sure fired comeback.
Ask the shop if he put a shelf unit in it??? What year??? Did they rebuild your transmission??? 95 is all on its own for ECM purposes. 93-94 will not work in a 95 vehicle. One piece case 93-95. 96 and up with a bolt on B/H will not work either. All of these units will bolt into a 95 vehicle. I get a lot of work from interchanges that don’t work out. Trust me the solenoids for TCC are different. PWM came into play for 1996. This could be a why no tcc command!!! ECM sees a PWM instead of an On/OFF solenoid.
As far as the vibration, unbolting the convertor doesn’t always tell the story. If it is out of balance it will cause a vibration like described. Who built the convertor??? CVS (Consolidated Vehicle Systems) and Precision of New Hampton balance their converters, a mom and pop may not. Did they put a different flywheel in??? Maybe the balance weight is missing…
Ask the shop owner to back up his work with a whole different unit. I have had to do it before myself. Parts would only cost him $300 (my cost on parts are; Convertor $75, kit $95 w/o steels, band $10, filter $6, shift kit $50 [yes every 4L60E I do gets a gil younger sk] shift plate $27, incidentals $25, total $288) for the peace of mind on both ends. If it still does it after a whole new unit you know it’s the vehicle for sure and he still has a transmission he can sell to somebody else. WIN WIN. If its fixed YEE HAA!!!
PM me for more direct help
Tranzman