Hi everyone,

So I bought my first Cummins a couple of months ago (2019 3500 Aisin).

I’m loving the truck, but shortly after driving it off the lot, I started to notice a slight sag of about 100 RPM part way through 2nd gear.

With constant throttle, the transmission shifts from 1st to 2nd just fine, then as the RPMs are climbing in 2nd, there’s a sag of about 100 RPM (e.g. drops from about 1600 to 1500 RPM) and then it keeps climbing a few more hundred RPM before shifting to 3rd gear.

There isn’t any flare, i.e. whenever the RPMs are climbing there’s torque being applied to the wheels.

However, there is a noticeable loss of torque (jerky feeling) when the RPMs are sagging that 100 RPM part way through 2nd gear.

The transmission then behaves normally through the rest of the gears.

It seems that the sag/jerkiness is more pronounced when the engine/transmission are cold, but the behaviour is generally always there.

It doesn’t seem to make a difference if I’m in normal or tow/haul mode. I posted a video of it on YouTube (see link below) to hopefully help everyone understand what I’m describing.

I took my truck into the dealership to look at this about a month ago when it had about 3500km (2200 mi) on the odometer.

They flashed my aisin TCM with the latest update, and did a quick re-learn, but there was no change to the ~100RPM sag in 2nd gear afterwards.

They told me that it’s behaving normally, and the RPM sag is the result of Ram’s attempt at softening the shift from 2nd to 3rd.

Something about the jerky nature of it just doesn’t feel right, so I thought I’d seek advice from this forum prior to taking it back to the dealership to ask for further warranty work.

Is this actually ‘normal’ behaviour for these aisin transmissions?

Any input, thoughts, or advice would be very much appreciated!

Thanks in advance!