At a steady speed i'm getting an occassional jerk in the drive train. Used to be just around 58-62 mph but now starting to also happen around 30-35 mph as well. Changed the filter twice in the last year and just recently replaced ALL of the fluid. No codes.

Any idea what this might be?




It has been this way for a number of years but it is getting worse and i would really like to find out what it is because it can't be good. Feels like it is just a matter of time before I have a major failure.

First you need to determine if it mechanical or electrical. Check your fluid for color and smell. If it is electrical, I am willing to bet you might be having intermittant electronic problems with 1-2, 2-3 shifting solenoids allowing pressure to go to the TCC solenoid. Could be anything from the grounds anywhere to the wiring harness internal to the transmission. Could be the connector at the tranny being wet with oil and in that case drop the pan and replace the O-ring at the connector. Check the resistance to the 1-2 shifting solenoid. Check the resistance to the 2-3 shifting solenoid and Check the resistance to the Torque Converter Clutch Solenoid. The torque converter clutch solenoid controls pressure to engage the mechanical coupling at the torque converter.

Do not put the cart before the horse and start to snap diagnose by replacing solenoids, wiring harness, ect.. Even some shops do that and when they do you will pay for it. Don't blame sensors unless you test them out first or have them tested out. If a shop tells you that this sensor is bad then you need to tell them why. If you get a justified answer like a specific resistance reading on a transmission input speed sensor then run and don't walk to the nearest exit.

Are you sure its your transmission? I could discribe the stumbling that I am trying to figure out on my 94 k2500 burb as a jerking while driving which I believe to be other than transmission related. Just a thought.

Well...I must have jinxed the dang thing. It won't shift out of first (could be second...goes about 30mph@2000rpms)gear today. I haven't done a search yet.

It is showing a code "DTC 87 - Transmission Gear Ratio Error" What does this code mean?


What is the usual cause for the transmission not to shift into 2nd? reverse seems fine.

Mp4037 the only reason that I can think of why your transmission will not shift out of first "electrically" is the Computer is not denying the 1-2 shifting solenoid. When that happens then the transmission automatically shifts into 2nd gear. You can try disconnecting the electrical connection at the transmission and see if you can get 2nd gear. I would also make sure that each and every ground connection you have is clear and tight. read some of my past posts. Believe it or not if it is an electrical problem vs a mechanical one your problem can be cheaper to solve.
Actually the 1-2 shifting solenoid might be grounding "shorting" elsewhere. and causing the solenoid to stay actuated, meaning the transmission to stay in first gear. It possible. It's also possible that your solenoid has a stuck check ball inside the solenoid causing the hydraulic pressure to keep the first gear ingaged even if the transmission's computer is cutting off the solenoid. Read the sticky and find the post that shows the connector for the transmission, find the 1-2 solenoid and check for continuity to ground on each of the pins (there is two). Check for resistance

Resistance between the two leads should be 18 to 24 Ohms. Set a multimeter on Ohms and check for resistance, if you don't get anything than reverse the two leads and check again.

Mp4037 the only reason that I can think of why your transmission will not shift out of first "electrically" is the Computer is not denying the 1-2 shifting solenoid. When that happens then the transmission automatically shifts into 2nd gear. You can try disconnecting the electrical connection at the transmission and see if you can get 2nd gear. I would also make sure that each and every ground connection you have is clear and tight. read some of my past posts. Believe it or not if it is an electrical problem vs a mechanical one your problem can be cheaper to solve.
Actually the 1-2 shifting solenoid might be grounding "shorting" elsewhere. and causing the solenoid to stay actuated, meaning the transmission to stay in first gear. It possible. It's also possible that your solenoid has a stuck check ball inside the solenoid causing the hydraulic pressure to keep the first gear ingaged even if the transmission's computer is cutting off the solenoid. Read the sticky and find the post that shows the connector for the transmission, find the 1-2 solenoid and check for continuity to ground on each of the pins (there is two). Check for resistance

Resistance between the two leads should be 18 to 24 Ohms. Set a multimeter on Ohms and check for resistance, if you don't get anything than reverse the two leads and check again.

Thank You for the quick response!!

Nothing like a new problem on a sunday night.

I will check out the sticky.

Can the truck be driven like this (to a shop if I have too) without further damage?

Gear is in my sig.

Is 30mph@2000rpms 1st or second gear?

Is 30mph@2000rpms 1st or second gear?

Sorry about not posting sooner mate but 30 mph 2000 and you should be able to tell me what gear it is in. It really depends what gearing you have. You could actually be in third gear at 30 mph. You might want to see if there is a fluid loss in your transmission. You should also hook up a pressure gauge and check the readings. Gear ratio error is TISS and VSS are not jiving with the computer readings. 5 volt reference signal to the computer. Take off the tiss and clean it off with rubbing alchohol and a white rag, see if there are metal shavings on the magnetic sensor. Same with the VSS.
Check resistance readings on both sensors. Clear historical codes in the computer and have a go.

Sorry about not posting sooner mate but 30 mph 2000 and you should be able to tell me what gear it is in. It really depends what gearing you have. You could actually be in third gear at 30 mph. You might want to see if there is a fluid loss in your transmission. You should also hook up a pressure gauge and check the readings. Gear ratio error is TISS and VSS are not jiving with the computer readings. 5 volt reference signal to the computer. Take off the tiss and clean it off with rubbing alchohol and a white rag, see if there are metal shavings on the magnetic sensor. Same with the VSS.
Check resistance readings on both sensors. Clear historical codes in the computer and have a go.

Looked for TISS in the stickey. Not sure what that means?

What and where is it?

Transmission input speed Sensor. The little device that counts all of the little teeth in a gear that sends pulses to the computer. The computer interprets those pulses. wide pulses mean a slow gear narrow pulses mean a fast gear. Think of a heart beat on a EKG machine a bunch of narrow pulses mean that the teeth of a gear are causing that pulse switch to turn on and off very quick.
TISS= Transmission Input Speed Sensor

Main purpose is input speed.

Computer can now detect slippage. Computer can detect slippage in..
2nd, 3rd 4th.
The computer can detect slippage of the Lockup clutch.

The computer can detect slippage in 2nd and that means it can detect slippage in other gears not just the lockup clutch in the torque converter.