Road Trip, I appreciate the reply. It was quite vexing, especially being a former professional technician. Luckily I kept my wits and remembered my diag training once I realized the symptoms and conditions were not permanent. The 2nd gear only was fairly straight forward, but the random loss of...
Zombie thread time!
Well, since my last post I figured out what the hell was happening to my Burban. So, I lost overdrive and had HARD shifting 1-2 and 2-3. My best guess was something internal to the 4L80e. But after not driving it for a week I had to use it to take my waste oil to disposal...
@NickTransmissions I certainly did appreciate your pointers, they certainly helped!
As for the transmission, I drove it in to work today and well.... unfortunately.... we have a failure. For an all too brief weekend, the solenoids had fixed this stubborn 4L80. Great and smooth shifts, couldn't...
Success!!! We have shifting! All 4 forward speeds and reverse!!! Looks like the little voice in my head that told me to replace the solenoids and pressure switches with the pan off was right.
In total I replaced the following:
1 Input shaft speed sensor (genuine GM)
1 Internal trans harness...
Hi all. Little bit of an update regarding my issue. Im only just now getting around to diving into this (life, work, kids).
Ok, so I verified my 10A fuse to the trans is good, Ive got source voltage at the trans connector pin when key on. I took a guess and decided to buy an internal trans...
Quick update: replaced the Input speed sensor with a Genuine GM sensor. No dice, still no gears but second and reverse. Though of note, there were metal particles on the old ISS I pulled out. My guess is Ill need a rebuild sooner rather than later. Ill have more time this Saturday to really get...
Ill have more time next weekend to dive into it. I checked the 10A Trans fuse in the drivers side dash fuse box. Intact and ok as the gauges died when i pulled the fuse and worked again once reinserted. Ill have to check for available voltage on the main plug itself.
Current scan tool is just...
Hi, I have a new to me 96 GMC K2500 Suburban with the 454 and 4L80e 195k on the clock. Carfax shows a decent amount of service, including trans fluid service ~30k miles ago. Currently, the 4L80e is in limp mode with only 2nd gear and reverse. I have NO DTC codes stored, active or pending...
Recent lurker and new owner of a 1996 GMC K2500 454 Suburban. Thought Id stop by and say hi. I was originally trying to find a GMT800 8.1 K2500 but those were unicorns and if one popped up it was gone before I could make contact with the owner. Had a family event occur that reduced the available...