SOLVED! 02 Trailblazer Transmission Replacement Issues [Solved]

[SmokeyMcBlazer]

Hi all,

Its been a while since I've been on here but I'm hoping that its still the same friendly and helpful place that it had been

I recently had the transmission crap out on me in my 02 Trailblazer. I bought a rebuild unit with all the upgraded parts that I've often read about for this truck. The reman is in the truck now but the truck doesn't seem to like it very much. It'll go into and move in each gear but as soon as it's put into any gear, it pops a fuse and throws a bunch of Pcodes (the list of codes is at work on my desk. I can post on Monday if needed). Also, it seems like first gear doesn't grab well until the truck gets moving and when shutting off the truck, the key won't come out of the ignition. If you hold the gear selector forward the key will come out but when you let go of the gear shifter, (with the key removed) the dash lights come back on and the battery light is lit. The tranny grabs fine in reverse and all the gears once its moving at all but from a dead start, it seems like it slips a fair bit. My shop had found a loose wire in the round electrical plug that goes into the transmission while removing the original transmission, but they repaired it. Between the shop and the builder they say the codes point to bad communication between the tranny and the truck. The shop says its in the transmission and the builder says its in the plug. I went to a scrap yard this morning and harvested 2 more plugs from trucks there. I'm gonna have the plug swapped out for one of the scrap yard units on Monday. The builder says that the transmission or truck is going into limp mode because of communication failure. Does that sound right?

Now I'm wondering if there is a dealer flash that needs to be done for my truck to recognize the different transmission maybe?

If anyone has any ideas of what might be going on there, I'd love to hear them. I'm almost ready to just give up and scrap the truck but I'm already this far in. If it might be just something simple that is being overlooked, I wouldn't want to be rash.

Someone knowledgeable please help me lol...

 

[Sparky]

No flash needed for the transmission, there's no vehicle VIN specific stuff there.

Which fuse does it pop?
Codes would be helpful.

Usually, issues with the battery light lit when the key is out is an ignition switch issue, but, it could be something else given it doesn't do that when you push the selector further forward... If you've never changed the ignition switch it may be worth doing just because it is cheap and rules out a funky coincidence.

It is possible the plug got damaged during the swap (they did find a bad connection there after all), however, if that doesn't correct anything it very well could be a bad/pinched tranny harness. Nice thing is that's relatively easy to inspect and replace if you have to. Just drop the pan and there it all is. If it is bad, the builder owes you a harness.

 

[mrrsm]

If the installer did not replace the Park Neutral Switch with a Brand New One or Boogered either of the Two Electrical Connectors when re-installing them ... your problem might be found there, as the OEM ones were Hot Glued in at the Factory and those plugs must be carefully removed if it was not simply slid completely off the end of the 4L60E Armature where it was held in place with a 13 (12mm ?) Nut with the plugs still attached. If either the Metripack Plugs and/or any of the Harness Wires were cut or compromised... this might explain the Fuses Blowing when the Shifter Lever is being actuated through the PRND123 cycling.

Putting the PNS back onto a different transmission in exactly the right position can get a bit sketchy.... That Key Problem for example is symptomatic of a PNS misalignment that the Transmission may not actually be IN the proper PARK Lever position to signal the Key-Lock that its okay to take it out of the ignition.

If you have to replace the PNS... prior to installing the Shift Cable Nylon slip-on cable button... manually actuate through each and every gear position (wheels blocked so the SUV will not roll over on you in Neutral) and follow the install instructions as to EXACTLY where to place the lever just before you carefully press the PNS exactly over and onto the Armature into the correct relationship and position.

The mis-alignment of that switch on the armature...and/or the poor adjustment of the switch via the two out board mounted 15MM (13mm)Bolts where the oval bracket is located can likewise Play Hell with the proper shifter position inside of the cab ...for whatever it says it is for the Shifter PRNDL123 image and whatever its ACTUAL position is on the 4L60E ...can be two completely different things.

If you can Elevate and Safely Support the vehicle and give everything a closer look down there... you might spot the issue right away and it will be an easy fix. When you are done... when installed, the two Black Connectors on the back of the PNS need to be Zip-Tied in REAL GOOD so their solid electrical contact connections are guaranteed. The attached image gives a perfect overview of the entire arrangement:

 

[Mooseman]

If it's blowing the tranny fuse, I'd say there is a short in the tranny harness, either internally or externally, or a bad solenoid in the tranny.

Your other problem with the key and shifter could be an issue with the shifter position sensor because normally, it won't let you take the ley out unless it's in P. Because it seems to work when you push on the shifter, it may just need to be adjusted.

 

[SmokeyMcBlazer]

Hey guys, thanks for taking the time to respond.

So, I still don't have my truck back lol but there is good news I think/hope. I took all the info that you guys gave me and applied my deductive reasoning.

Ok, a little more history first because I know you guys love a story lol...

When I said that my shop found a loose wire in the round electrical plug I forgot to mention that their first thought was "Just chop that damn thing off"! So they chopped the plug off the truck. They also didn't know about the hot glue in the park/neutral switch. They had wedged a screwdriver in the connection trying to get it out and cracked the PNS. So they once again thought "Just chop that damn thing off"! So they chopped the plug off the PNS and left it on my dead tranny. The builder didn't have a new one but found a used one under his bench. He used his torch and gently heated the PNS and pulled the plug out with ease lol.

So, long story short. I went into the shop monday morning to drop off the scrap yard electrical plugs and lost my shit. I told the owner that I was pissed off because his damn butcher hacked all the wiring out of my truck. I showed him the wiring on the scrap yard plugs and there are like 3 sets of the same colours of wire in the harness! I asked him how his shoe maker in the back knew which pink with stripe wire went to which one in my truck? I continued to berate him for about half an hour while he blankly stared at the wires in the harness. I told him that one of two things was happening. Either he was gonna send my truck to an auto electric shop on his dime. Or he was gonna give me back all my money and I would take it to the electric shop to fix what his butcher had done. The last thing I told him before I left the shop was that I wouldn't even bring a wheel barrel there to get a tire pumped up.

Now my truck is rewired but the used PNS that the builder gave to me isn't communicating with the truck so the electric guy wants another one. I told the original shop owner that he was covering that cost too.

All I can say is that I hope to fawk that there's actually no problem with the tranny because if there is, I'm not sure how I'll yell my way out of this one lol!

 

[SmokeyMcBlazer]

Great news everyone!!! My truck is done and working better than ever!! The original shop owner bought a new PNS and the electrical shop installed it today. I just got home with it and everything is working cherries!! Thanks again for the helpful responses guys!! Much love , you guys helped save my baby!!!

 

[mrrsm]

Welcome Home, Smokey! (Don't Forget to Edit The Post Header as [SOLVED]

 

[Mooseman]

Glad it worked out.