Jump to content

Stuck In 2nd

MrGoodWreck

By MrGoodWreck
in Ask A GM Technician

Recommended Posts

MrGoodWreck Enthusiast

MrGoodWreck

Posted
Posted

2005 Silverado SS - Engages hard into gear (both forward and reverse). Starts in third unless you pull it into low (1). When pulled into "1" it starts in 2nd and will shift to third when put in 3 or Drive. If left in 3 it will accelerate and decelerate with the engine. In Drive it will free wheel when off the gas.

 

It's been intermittant and now is a hard fault. Codes are P0 740, 753, 758, 761, 785 and P2761. It seemed to have the problem if the first thing I did was back up after starting.

 

It has power on pin E at the trans (pink wire). I dropped the pan and there is power to each solenoid. How do I troubleshoot the ground paths back through the PCM ? Any help out there ?

 

:cool:

cammiller Enthusiast

cammiller

Posted
Posted

The odds of all those codes being set are slim unless the the plug is off the side of the transmission. What did you use to test the power at the solenoids? If it was mine I would put a switch in it. They are very cheap- retail GM is $40 or so.

MrGoodWreck Enthusiast

MrGoodWreck

Posted
  • Author
Posted

Thanks - I inspected and cleaned both the trans connector and PCM connector. I measured voltage at the solenoid pins inside the trans so I conclude that the connector is not the problem - at least on the power side of the circuit. When this was first happening intermittantly, I replaced the switch module on the left side of the trans. but no change.

 

I think it must be on the ground side of the control circuit. They are all grounded through the PCM as far as I can tell. I also cleaned all the wire harness ground points on the chassis.

 

Any other thoughts ?

  • 1 month later...
gmtech04212007 New Member

gmtech04212007

Posted
Posted

Replace the ignition switch

It is problem that has to be explaind to understand

First of all the IGN 0 fuse in the fuse block inside the vehicle powers the 1 pink wire to the transmission connector. There must be battery voltage at that wire... 12 volts ... no less

now that 1 wire splits up into 5 wires to power all the solenoids in the transmission.

Each of the solenoids have their own ground through the pcm

When all these codes set it is hard to believe the pcm is the issue due to 5 seperate ground wires (possible but unlikely) What ususlly happens is an interminent short in the ignition switch the powers the ING 0 fuse

this short or open only has to last for 3 seconds and the code pops

during this time the power can go back to normal (switch powers the correct voltage) but tranny goes into limp mode untill codes cleared

 

so my advice put in a 50 dollar ignition switch

 

and let me know how it works out

minibike132 Senior Enthusiast

minibike132

Posted
Posted

+1 on the switch, if it is a hard fault now you can check that circuit. If it was intermittant I would throw one at it based on about 100:1 odds. If it's happening now check out the circuit just to be sure.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • BDS my HD
      Brand new to this forum. Questions about re-gearing my 26’ HD

      By BDS my HD · Posted

      Hello hello looking forward to expanding my knowledge of the 2026 2500 HD that I just bought.   Truck has 3500 miles on it four-wheel-drive crew cab and I’m about to put a 6 1/2 inch BDS lift on it 18 x 10 -25 offset with 37’s   Already have the wheels and tires just waiting on the lift install in about three weeks   Question what surprises am I not gonna be happy with?  I’m not new to lifted trucks so I know that acceleration towing gas mileage all that is affected..   Question is those of you that have this truck this powertrain with a 10 speed Allison and have done the mods that I’m doing,,, how bad is it? Is that Allison constantly gonna be hunting for the right gear to go into? And what about towing, acceleration, fuel consumption as mentioned?    Lastly how come I can’t find any ring pinion gear set up for these axles and when could I expect to see them?   I apologize if there’s any typos I’m doing speech to text on my iPhone.    
    • linc45bn
      2013 2500HD 6.0L intermittent no crank no start

      By linc45bn · Posted

      I've got a 2013 2500 6.0L Flexfuel. Drove the truck earlier today with no issues. Went to run an errand tonight and noticed key fob wouldn't work. Figured battery was dead, so replaced fob batter. Still wasn't working. Grabbed my other set of keys with the other fob and that one wasn't working either. So I manually unlock truck and insert key. Interior lights come on, dashboard lights up, turn key and truck starts. Turn truck off, like a moron, and try starting again. This time no crank, no click, no nothing. Lights still come on and dash lights up, but now I'm getting a service 4wheel drive, service tire monitor, etc. Check voltage on battery and Im showing 12.2v. Throw my battery charger on it and give it 15 mins and try starting again. But still no crank no start. Decide maybe its a bad battery, run to autozone grab a new one and put it in. Same issue. Disconnect battery and let it sit for 15 mins. Try again and still nothing. I had managed to roll the windows down earlier as its a humid night, but now I can't get them to roll up. Power locks are also not working now. Then randomly I try the key again, and it fires right up. Immediately I roll up the windows as we have nothing but rain forecast this week. I shut it back off wait 30 seconds and start up again. Worked a 2nd time. So turn it off, start putting things back together. Try one more time, and back to no crank no start. And now the car alarm starts going off. Had to disconnect battery and leave it that way for the night as I don't think my neighbors would appreciate my alarm going off again tonight. Any thoughts or help would be appreciated. 
    • Grumpy Bear
      first oil change - 2026 2500HD gas

      By Grumpy Bear · Posted

      No one will care for you like you care for you. Do what you can for as long as you can. IMHO of course. 
    • Grumpy Bear
      Oil Consumption

      By Grumpy Bear · Posted

      How about them NICKS!!! 
    • Peoplemvr
      GMC 1500 Illuminated Front Grill Emblem REPLACEMENT.

      By Peoplemvr · Posted

      Hi there.  Long time lurker, first post.    i have read the previous posts regarding the water ingress problem with this emblem.  I bought my 1500 SLT the  summer of 2025 new and after reading the MANY problems with these emblems failing I decided to install one anyways.  As per a YouTube video, I sealed ( or tried to) this sign with silicone sealant around the outer perimeter joint and the holes that were already somewhat sealed on the rear plate of the emblem.  And installed the connector assembly using dielectric grease on the connectors. The installation looked great and worked well for about 4 months……then FAILURE.  Grrrrrr…… I live in the great white north and wash my truck weekly in an automatic car wash  to keep the salt off.  Let me tell you that removing the old, failed emblem is a whole different animal than removing the OEM individual letters without removing the grill assembly. Mainly because the illuminated logo is built differently than the original letters which  you can remove the red surface lettering with a knife or some kind of blade which gives access to the tabs which hold the logo onto the grill. So I had to essentially destroyed the old emblem to remove it. Doing so killed my chance of doing somekind of autopsy on the failed , old logo.  But there was plenty of water inside when I ripped it apart.  Prior to installing the new assembly I tried it with the old harness and it works fine.   Does anyone have any insight as to where the water is getting into this emblem? I intend to seal the new logo with slow curing epoxy this time around using a syringe.  I think this newer emblem may be an updated unit which I hope GM got the vendor to fix. It has an October 2025 date on it.    If this one  fails,  I am just going to revert back to the non-illuminated letters….AFTER PULLING THE GRILL.    Any thoughts on sealing with epoxy would be appreciated. Thx!   Doug  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...