Hey guys,
Just removed a pressure control solenoid from a 4L60E and I have a question. I was told by a person at O Reilly that you can increase the line pressure by turning the torx screw by 3/4 turn and it will help with shifting gears as I have removed the shift solenoids and they checked out at 22.5 ohms as did the TCC and PWM. No broken connections on the harness and the torx screw does not want to move freely. Is it maybe bad or should I try to force it to move? He told me that he talked to someone and it fixed his shifting problem. Does this sound normal? I wanted to get advice from the experts on here as I am a newbie when it comes to transmissions. Also since I am a newbie on the forum, should I go back to my original thread to edit and update or start a new one. I don't want to violate rules and such. Any help is much appreciated.

 

The PCS is calibrated to ensure that a particular input will yield a corresponding output. The pressure is altered by the PCM and shift adapts are learned. By altering the calibrated setting of the PCS, you could just mask problems or create others. There is a reason why you don't find much (if any) information about doing such a thing.

If you were to experiment with it, I wouldn't go beyond a 1/4 turn. A little change can make a big difference. Too much line pressure can cause harsh shifts that can potentially damage hard parts in the transmission. This is an experiment that can end up costing you a LOT if it doesn't pan out.

 

Thank you for the info. I took your advice and moved it 1/4 turn. It did not make a difference and I still have the same problem. I did some more research on the forum and I did buy some CRC MAF sensor cleaner and gave that a shot because of the advice that you gave and it turned out that it was dirty and needed to be cleaned but it didn't help the trans. I have a question about the 2-3 shift solenoid though. I understand the electrical part of it such as it seems to have power supplied and it is just waiting for the ground to be applied from the PCM when needed. I checked the coil with my DVOM and had 22.5 ohms on the coil so I didn't replace it BUT what about the mechanical workings of the coil. Should I have replaced it anyway since I had the pan dropped even though the coil checked out. Also I noticed when I test drove it that the fuel gauge is very erratic and travels forward until the voltmeter for the battery stops it movement. My wife has not mentioned that or has said anything about the speedometer. I was wondering if the TSS has anything to do with other gauges as it does for the speedometer and if that could also be responsible for the trans not wanting to go from 2nd to 3rd. So far I have not found any wiring problems or open fuses. Sorry for all these questions, just looking for help without wasting tons of money on something I don''t need.

 

If the coil resistance is in spec, the solenoid is likely fine. That doesn't mean that the 2-3 shift valve isn't stuck in it's bore, but before getting too deep on that, lets go over what the truck is actually doing...?

 

OK, Reverse 1 and 2 shift fine. When it is time for 3rd, it does not engage and revs like it is in neutral.

 

I hate to tell you this, but it sounds like your 3-4 clutch pack is gone.

A no 2-3 shift could be caused by a stuck 2-3 valve train as I indicated above. The only way to really diagnose that kind of problem is to drop the valve body and go through it.

 

Hi swartlkk,
Thanks for the quick response. You have me confused. Is the 2-3 solenoid also referred to as the 2-3 valve train or is the 3-4 clutch packs also referred to as the 2-3 valve train. Sorry I am a newbie on trans. and your professional jargon is new to me. I was told that the bottom of the pan didn't have any black goo or anything but I didn't change the filter and fluid myself so I was hoping the clutch packs and bands were still OK. You mentioned removing and inspecting the valve body to diagnose the problem. What would I be looking for or are you saying that I should get a Transgo kit or another shift kit and rebuild it? I thought about doing that when I had the pan dropped but I have never done it before and I watched some videos online and I was afraid about getting those 1/4" ***** back in the right place because I wanted to rebuild it without dropping the whole tranny.

 

If this is new, I don't recommend that you pull the valve body yourself unless you have hands on help from someone who knows what they are doing.

Nothing I have stated is referring to anything else. The solenoid is separate from the 2-3 valve train in the valve body and the 3-4 clutch pack is just that, a clutch pack.

You cannot rebuild a transmission without removing it from the vehicle. You can recondition the valve body with the trans in the truck.

If you are interested in trying to work on the valve body, I recommend a good reference manual. ATSG has some affordable books on the 4L60E and there are several good tutorials online that can be found through Google.

If the 3-4 clutch pack is fried, a valve body reconditioning won't have any affect on your problem.

 

Need help with my trans also,I have little to no 1st gear shift all the other gears are shifting fine though although it doesnt to have passing gear at times either..Should I replace the boost valve on the bottom of valve body and or change the 1 gear solinoid?The trans is a 94 4L60.I`ll be doing a complete trans fluid drain and replacing the filter in a couple of days.

 

I was told by a transmission builder you can adjust the pressure control sylinoid to increase firmer shifts.