Will the car still function if I remove the shift interlock solenoid?

[showme]

I'm working on my grandson's '08 GP and I need some advice. He was starting to have problems shifting out of park and was also having 'reduced power' (limp mode) until it got so bad he called me for help. From what I've learned, the possible culprits for the shifting problem are the brake pedal position sensor, the shift interlock solenoid, and that the accelerator pedal may be one reason for the limp mode. I know the throttle body might cause this too, but I replaced that about 2 years ago with a GM OEM part.

I've put a new brake pedal position sensor on, and a new accelerator pedal/sensor just in case. I have a new scan tool arriving today to calibrate the brake pedal sensor. As of now, after putting those parts in, the car starts, the shifter moves (sometimes), but when I put it in any gear it revs but doesn't kick into gear. I'm hoping this will clear up after I re-set the brake sensor. 

My question is about the shift interlock solenoid. After not finding new ones anywhere, I ordered a used complete shifter with a solenoid on it after asking the seller if the solenoid was for sure good. He said it was, and it's on the way. But if I remove the interlock solenoid from the shifter, would everything still work as normal (aside from the fact that the shifter would no longer need to be in park to complete the start up? Is there anything in the circuit between the brake pedal sensor and the shift interlock solenoid that would keep the car from starting or running correctly? I've already pulled the solenoid but didn't try to start it and check it yet. The car is sitting in the high school parking lot where my grandkids are students. 

 Anyway, the scanner comes in today and the "new" shifter assembly will be here in a few days. I'm wondering if I get the brake sensor calibrated and can get it running and shifting if it would be safe (me driving) to drive back to my house to finish the job. Also, if anyone has any suggestions about troubleshooting the reduced engine power/limp mode, I'd appreciate any help or comments on that. Thanks for any help on this. Lee

Edited Monday at 07:00 PM by showme

[showme]

Update- So the new scanner didn't perform as expected, so i had my mechanic come out and recalibrate the brake pedal position sensor and he told me the car is starting (which it did already), and the shifter is moving into gear but it isn't engaging and he thinks it may be the transmission. I'm not sure how the transmission can cause reduced power, but it makes since that it's causing shifting and gear engaging problems. I just don't want to pay to have the transmission rebuilt and then have it turn out to be something else, i.e., more simple and less expensive. 

  My daughter is a single working mom with 3 teenage kids, one in his first year of college and the other two in high school. I should be finishing up on the grandson's car repair today. (He went off the road and I've replaced his radiator, condensor, fan, low pressure AC hose and a new compressor is coming in today.) Hopefully I'll have it back on the road by this evening. But with my daughter working full time as a nurse, and the 3 kids all in school and working, they are all depending on her Ford Expedition and its' wearing them all out. Any help or ideas on this will be appreciated. 

[55trucker]

Are you absolutely sure that the shifter mechanism on top of the case is properly aligned?

It is an electro/mechanical device that has to properly positioned.

The engine is the 3.8 or 5.3?

The trans IS the 4T65e?

Edited Wednesday at 08:16 PM by 55trucker

[showme]

No i'm not absolutely sure it's alligned. I wasn't aware it needed to be. It's my grandkids car, and I'm an Ironworker, not an auto mechanic. It's a 3.8. No idea what transmission is in it. 

[55trucker]

The *Neutral Safety Switch* doesn't have a single *install & forget it* position, the switch can be rotated.

The switch slides down over the selector lever that extends above the trans casing, one has to rotate the switch assembly into the correct position & lock it down for accurate trans shifting.

One usually does so from the park position. If it's been moved it can cause what you're experiencing.

 

 

 

Edited Friday at 02:26 AM by 55trucker

[showme]

Ok, thanks. I will attempt to check that. The shift interlock solenoid and maf sensor came in yesterday, and I have a pcv valve and hose coming in today. To be honest, I'm ready to have it towed to the transmission shop. I've been working on another grandson's '13 vw passat for weeks after he tore up his front end. I'm getting worn down with all these unexpected problems. And I've decided it's my last run as family mechanic. For me, anyway, it's one thing to confront a problem I'm familiar with and fix it, but the constant sinking new parts and time into things that seem to have unexplainable reasons to not work has burned me out. I take my Silverado 3500 diesel to my mechanic when the problems are over my skill level. But I still like working on my '51 Chevy 3100 since it doesn't have lots of unnecessary electrical details. 

[showme]

Ok, yes, it does still function without it. I installed the new shift interlock solenoid, and it worked great. Too great. When i tried running the shifter through the gears, it worked fine. Until I tried to pull the key out of the ignition. It was stuck like glue. I tried every trick I knew and a few other people knew. Key wiggling, shifter pushing, steering wheel cranking to the far sides, disconnecting the battery, pushing on the interlock cable, pulling on the interlock cable, and a few more I can't remember right now. After leaving the car in the parking lot with its key in it last night (hung a roll of black gorilla tape over the key. It wouldn't go anywhere if they did get in and start it, anyway). Today I pulled the dash apart to try to get to the ignition switch so I could pull the tumbler cylinder out and work on it that way. As I was triggering the cable, I watched it as i pulled the shifter trigger button that releases the shift interlock solenoid. I reached down and grabbed the dead end of the cable on the back of the rocker that pulls it, I found that there was enough slack in the cable that i could pull it another 3/32" more cable past the point of where the rocker pulled it to. I tried pulling the key out and it came out! Apparently, the cable/wirehas stretched. I tried to figure out a way to crimp something on or adjust the rocker that pulls the cable, thinking maybe a lead fishing sinker crimped on there may work. But then I thought about the grandkids having it come uncrimped or slide up and going back to square one, so I disconnected the ignition switch end of the cable from its housing and it worked. I then thought, well, if that works, I wonder if it even needs the solenoid on there, so I tried it with the solenoid off. Still works. I checked for dash warning lights, went through the gears and it still functions fine. So the $80 solenoid is going back for a refund. I was a little worried about the car starting in gear, but it won't. It will start in park and neutral, but not in any of the driving gears, including reverse. I'm going to get them a new cable and install it sometime, but for now, it's fixed. Sort of. At least I don't have to buy a $200 ignition tumbler and have it recoded. Now, I just have to figure out what's wrong with the tranny. The shift cable is good and is switching through all the positions at the arm on top of the transmission, but it's not engaging in any gears and neutral isn't letting me role any. But at least the key isn't stuck anymore and I think I've fixed the problem with the shifter. Onward, to the next problem!

[55trucker]

Moving the trans selector into any gear gets you no vehicle movement?

When in any selected gear do you hear any sort of whining that changes pitch & volume as you increase engine rpm (altho you're not moving)?

That would be a sign that the trans pump is/has failed. It's no longer producing any needed pressure to supply to the valve body/clutches to properly operate the trans.

Edited 1 hour ago by 55trucker