SURGING PROBLEM

[eller123]

I have a 2007 Winnebago Adventurer Model 35L with a Workhorse Chassis with a 8.1L Chevy engine and a 1000 model six speed Allison Transmission. While running on level terrain at about 60 to 65 mph the tachometer starts surging from 2,000 rpm up to 2,500 rpm as if the transmission is trying to shift but never does. I may have driven anywhere from 25 to 30 miles before it starts surging. The surging can go on for 2 miles or as many as 100 miles then stops and goes back to normal operation. I have had the Transmission rebuilt, replaced the ECM module and replaced the spark plugs and wires. Additionally, I have taken my coach to Allison’s main district area shop in Houston, Texas, and other locations. I was told that without the Check Engine Light or a Code indicating that there is a problem, that this issue cannot be diagnosed and therefore the problem is unable to be repaired. I would welcome and greatly appreciate any ideas or solutions that may provide a “fix” for this problem.

[Stim]

I guess the OP fixed it. ???

[PaulJ2]

wolfe10 wrote:

PaulJ2 wrote:

Stim wrote:
That sure sounds like Torque Converter Lock Up in and out.
I have had GM Vehicles that you could feel when lock up occured and it felt like another gear shift.
Something to try, when it is working normally, tap the brake pedal but don't push hard enough to apply the brakes, just enough to turn on the brake lights. That will cancel lock up and when you let go of the brake you should feel lock up again.
Watch the tach to see if it is the same issue.

I too believe it could be either a defective or missadjusted brake light switch, unlocking and relocking the torque converter.

Would that also activate the brake lights? If so, either someone following you OR driving at night and seeing in the rear view camera if brake lights come on would be pretty easy diagnostics.

Yes it may activate the brake lights, UNLESS---it has a separate set of contacts for converter unlock.

[Krusty]

Would be helpful if you could monitor or record live data as the fault is occurring. I would definitely try lightly applying the brake pedal while it is surging to see if it goes away. It may be a faulty throttle body too.

[wolfe10]

PaulJ2 wrote:

Stim wrote:
That sure sounds like Torque Converter Lock Up in and out.
I have had GM Vehicles that you could feel when lock up occured and it felt like another gear shift.
Something to try, when it is working normally, tap the brake pedal but don't push hard enough to apply the brakes, just enough to turn on the brake lights. That will cancel lock up and when you let go of the brake you should feel lock up again.
Watch the tach to see if it is the same issue.

I too believe it could be either a defective or missadjusted brake light switch, unlocking and relocking the torque converter.

Would that also activate the brake lights? If so, either someone following you OR driving at night and seeing in the rear view camera if brake lights come on would be pretty easy diagnostics.

[PaulJ2]

Stim wrote:
That sure sounds like Torque Converter Lock Up in and out.
I have had GM Vehicles that you could feel when lock up occured and it felt like another gear shift.
Something to try, when it is working normally, tap the brake pedal but don't push hard enough to apply the brakes, just enough to turn on the brake lights. That will cancel lock up and when you let go of the brake you should feel lock up again.
Watch the tach to see if it is the same issue.

I too believe it could be either a defective or missadjusted brake light switch, unlocking and relocking the torque converter.

[allbrandauto]

the torque converter on the Allison locks up between second and third gear. you said the trans was rebuilt why. was the problem there before overhaul

[Stim]

That sure sounds like Torque Converter Lock Up in and out.
I have had GM Vehicles that you could feel when lock up occured and it felt like another gear shift.
Something to try, when it is working normally, tap the brake pedal but don't push hard enough to apply the brakes, just enough to turn on the brake lights. That will cancel lock up and when you let go of the brake you should feel lock up again.
Watch the tach to see if it is the same issue.

[eller123]

Thanks to all of you who have sent suggestions and ideas of things that might help with finding a solution to my problem. Some of you have had additional questions which I will try to address. I have 80,000 miles on my RV. I have been working on this problem since September, 2019. I find that after the engine is up to normal running temperature and drive 20-25 miles, the surging starts. However, there have been instances where I have gone 40 to 200 miles and some distances in between before I have experienced the surging which I will define more in depth later on. The miles driven before the surging occurs have not been at a specific number of miles. The RV has a 8.1L Workhorse/Chevrolet engine that operates on a Throttle body Assembly with a wire not a cable. To date I have changed the fuel filters, plugs and wires, the transmission has been totally rebuilt with new torque converter, pump, bands and sensors. Additionally, I have changed the TCM Module and had it flashed. What I mean by surging is the tachometer will start surging from 2,000 up to 2,500 rpms and then back to 2,000 rpms. The engine appears to go up in speed as if it is trying to change gears but this does not happen. When the engine appears to be trying to go up in speed the speedometer is not reflecting ANY change in mph. The indication of any change in the engine speed is an audible sound only with no indication of a speed increase on the speedometer. I have made a video of the tachometer and speedometer while running that clearly shows the tachometer surging to 2,500 rpms with the speedometer staying right on the same speed whether 60 or 65 mph. The video picks up the sounds of the engine trying to shift. The amount of time that the surging takes place varies. When it does stop everything goes back to normal operation. It appears that if the transmission is in 6th gear it stays there and does not shift to 5th gear even though it sounds like it is trying to do so. The same thing happens if the transmission is in 5th gear. It stays there. I am in the process of changing out the HO2 sensors and the Manifold Absolute Pressure (MAP) sensor. I hope this clarifies some of your questions.

[RLS7201]

To add to the torque converter thought. Have you added LED stop light bulbs? The stop light wires need to be pulled to ground when not in use. LED bulbs won't allow this to happen. I learned this the hard way on my MH. LEDs will also cause a cruise control problem. I added a 194 bulb and socket to each stop light wire to cure my problem.

Richard

[Stim]

boogie_4wheel wrote:
Sounds like the torque converter is unlocking them locking back up. Most scanners and even free phone apps and using a bluetooth dongle will show torque converter clutch (TCC) status. Watch to see off the command is being lost to lock. If the command is not changing, then tapping the wiring at the trans and adding a light might be needed to prove a weak connection to the solenoid.

Unfortunately most mechanics will not pursue without a CEL as a starting point. And at $100+/hr it can get costly for a shop to try to track down an intermittent problem.

I had a TCC lockup solenoid fail on a 4L60E that resulted in weak and no lock conditions. It was easy to access requiring only dropping the pan. I don't know where it is on the 1000.

Just an additional thought about the converter lock up- Have you had any issues with the brakes?
Why I ask is applying the brakes cancels lock up. If a brake issue were causing brake pressure in the system it might cancel lock up. ???
Did Workhorse ever have brake hose issues?
Just a wild guess outside of the box.

[boogie_4wheel]

Sounds like the torque converter is unlocking them locking back up. Most scanners and even free phone apps and using a bluetooth dongle will show torque converter clutch (TCC) status. Watch to see off the command is being lost to lock. If the command is not changing, then tapping the wiring at the trans and adding a light might be needed to prove a weak connection to the solenoid.

Unfortunately most mechanics will not pursue without a CEL as a starting point. And at $100+/hr it can get costly for a shop to try to track down an intermittent problem.

I had a TCC lockup solenoid fail on a 4L60E that resulted in weak and no lock conditions. It was easy to access requiring only dropping the pan. I don't know where it is on the 1000.

[Lwiddis]

See response to your 12:28 identical post.

[MrWizard]

Put a scanner on it while driving
One that will record and save all the diagnostic data and codes
You need real time operation data

[allbrandauto]

need more information when you put your gear shifter in drive and it reads what gear your in does go from fifth to sixth with the rpms surging