Forum Discussion

eller123's avatar
eller123
Explorer
Jan 30, 2020

SURGING PROBLEM

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.
Class A
  • boogie_4wheel's avatar
    boogie_4wheel
    Explorer
    Jan 31, 2020
    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.
  • MrWizard's avatar
    MrWizard
    Moderator
    Jan 30, 2020
    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's avatar
    allbrandauto
    Explorer
    Jan 30, 2020
    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
  • Flute_Man's avatar
    Flute_Man
    Explorer
    Jan 30, 2020
    It also might be the speed sensor itself maybe near the transmission or the fly wheel. They generally are just encoders send out pulses based on the speed.
  • rgatijnet1's avatar
    rgatijnet1
    Explorer III
    Jan 30, 2020
    Fuel filter needs to be changed or impending in tank fuel pump failure.

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