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carringb's avatar
carringb
Explorer
Jul 23, 2012

Anyone knowledgeable on the Aisin (Ram) 6-speed?

One of my trucks ('08 Sterling 4500) is showing some shifting errors under light to moderate throttle. Heavy throttle it generally shifts fine. Intermittently it will miss the 1->2 shift, and hold 1st until it hits the fuel cutoff at 3200 RPM, then it makes the shift. I've also have it not make the 2->1 downshift at WOT. Also had it once rev up like its in neutral, and slam into 1st, as I was trying to pull away from a stop sign on a mild grade.

Fluid looks good. We run the recommended Mopar stuff. We change the fluid and filter every 7,500 miles (standard practice for us on all of our class 2-5 trucks). No codes.

Has anyone else experienced this? There are 300-some data channels for the transmission. We can monitor 12 at a time. Any suggestions which one to monitor?

Truck has close to 70,000 miles. Empty weight is around 10,800 with full fuel. Loaded weight is usually less than 16,000 pounds combined. This is a recent development in the last month. Yes, the transmission has alway had some shifting quirks, but this is new, and its twin does not do this.

Thanks!

36 Replies

  • SoCalDesertRider wrote:
    A 4500/5500 cab/chassis truck used for commercial purposes is often a very heavily used and abused truck. It's service intervals would fall under the 'severe' category. If the owner's manual says change it at 7500 miles, that's what I would do.


    The manual says 60,000/120,000 miles depending on duty cycles.
  • A 4500/5500 cab/chassis truck used for commercial purposes is often a very heavily used and abused truck. It's service intervals would fall under the 'severe' category. If the owner's manual says change it at 7500 miles, that's what I would do.
  • I'd agree that changing fluid that often is a complete waste.
  • Changing tranny fluid and filter every 7500 is a bad idea on any auto tranny. The secondary clutch material is filtered out and can't be used as additional friction. Sounds like a 1-2 clutch issue. I am by far not an expert in this arena, just passing on some tidbits I picked up a while back from a tranny builder.

    Mav