4L80E Erratic shifting and speedometer
Thread Starter
Registered User
Joined: Jun 2012
Posts: 12
Likes: 0
From: Idaho
4L80E Erratic shifting and speedometer I have a 2004 Chevy Silverado 2500HD with the 6.0L, 4wd, 4L80E transmission and only 156,000 miles. Recently (after a Jiffy Lube transmission flush and filter change) started acting like you see in the video below.
The transmission will shift based on where the speedometer is. So if the speedometer hits 0 or close to it, the transmission will down shift to where the computer thinks the rpm's should be. The transmission shifts hard and no where near normal. I replaced the speed sensor before taking this video (which goes into the transfer case) with no effect.. Does anyone have any ideas of what could be causing this? Also, the ABS light is on and I scanned the codes and it said the "rear vehicle output sensor", "steering wheel position sensor", and "front passenger tone wheel" and the only other warining light on the dash is for the air bag..
The transmission will shift based on where the speedometer is. So if the speedometer hits 0 or close to it, the transmission will down shift to where the computer thinks the rpm's should be. The transmission shifts hard and no where near normal. I replaced the speed sensor before taking this video (which goes into the transfer case) with no effect.. Does anyone have any ideas of what could be causing this? Also, the ABS light is on and I scanned the codes and it said the "rear vehicle output sensor", "steering wheel position sensor", and "front passenger tone wheel" and the only other warining light on the dash is for the air bag..
Registered User
Joined: Aug 2012
Posts: 1
Likes: 0
We are sorry to hear about this experience and we're reaching out on behalf of Jiffy Lube to find out more. Could you e-mail us at jiffy-lube-customer-service@shell.com and share the date of service, the name the vehicle was serviced under, the location you visited, and or the license plate of the vehicle, and any additional information regarding your experience you would like to bring to our attention? We look forward to connecting!
I'm having a veryh similar problem with my 4L80e. Speedometer is acting erratic, trans feels like it's slipping and the converter is locking up whenever it wants to. Fluid level is good. I'm about to start a thread of my own.
Thread Starter
Registered User
Joined: Jun 2012
Posts: 12
Likes: 0
From: Idaho
Checked the fluid level... and it's full, but here are some findings from today:
I crawled under it today to look at wires and saw on a couple other sites that there were 2 speed sensors in the transmission so I wanted to look at them and check for loose connections. When I got under the truck, there was a LOT of mud, so I hosed off the transmission the best I could and then took it for a drive around the block. Shifted PERFECTLY and the speed was accurate.
My friend came over later and we went for a drive to his place and the transmission started shifting weird and what seems to be based on the speedometer speed still. After doing what we needed to at his place, drove home and it still did as shown in the video.
About 10 mins ago we were going to take it to the local transmission place but before leaving decided to spray the transmission with water as before just for kicks. Sprayed it down, got in to go.... Shifted perfectly again and the speedometer was accurate again.
Took it for a 8-10mile drive and it worked the whole time. Turned it off... turned it back on and still drove ok.
I'm going to investigate further tomorrow in the day light and see if it shifts bad again after drying all night and look for loose connections that maybe the water is effecting.
I crawled under it today to look at wires and saw on a couple other sites that there were 2 speed sensors in the transmission so I wanted to look at them and check for loose connections. When I got under the truck, there was a LOT of mud, so I hosed off the transmission the best I could and then took it for a drive around the block. Shifted PERFECTLY and the speed was accurate.
My friend came over later and we went for a drive to his place and the transmission started shifting weird and what seems to be based on the speedometer speed still. After doing what we needed to at his place, drove home and it still did as shown in the video.
About 10 mins ago we were going to take it to the local transmission place but before leaving decided to spray the transmission with water as before just for kicks. Sprayed it down, got in to go.... Shifted perfectly again and the speedometer was accurate again.
Took it for a 8-10mile drive and it worked the whole time. Turned it off... turned it back on and still drove ok.
I'm going to investigate further tomorrow in the day light and see if it shifts bad again after drying all night and look for loose connections that maybe the water is effecting.
Teching In
Joined: Jun 2016
Posts: 1
Likes: 0
Cliff hangers are my biggest peeves on these forums. People are quick to post & ask questions but rarely come back with follow-ups or updates. This could have been a useful thread...
I suspect from the symptoms, that part of the issue was the Main Transmission connector. They tend to leak and seep fluid causing electrical problems... YEARS later.
I suspect from the symptoms, that part of the issue was the Main Transmission connector. They tend to leak and seep fluid causing electrical problems... YEARS later.
