Without anything needing to be done on my Ram today other than vacuum carpet from dirt and little pieces of plastic after replacing dash, and checking the oil, I tend to over think things.

Two weeks ago, took the Ram on a 1000 mile trip to Houston and back. Got about 11mpg. Truck ran good, but darn, can't afford that! Yota gets 17! I noticed that at 70 mph in OD, rpm is about 3200. Is this normal? Seems pretty high to me.

 

What gears and size tire? Mine with 3.55's and 245/70/16 tires would run about the same rpm in 3rd.

 

I have a Corporate 9.25 LD Rear Axle - 3.55 Rear Axle Ratio with P245/75R16 tires…..stock from factory.

 

Are you sure your overdrive kicked in? The rpms should be around 1800 at 70mph with your tire/gear combo.

 

According to Snap On MTG 2500, yes.

 

I'm not familiar with the Snap On but does it show what gear you're in or does it show if the TC is locked? The scanner I've got only shows if the TC is locked but it ain't no Snap On . Did you try hitting the OD button to see what happens? How many times do you feel it shift? Does the engine sound like it's turning a lot of RPM or is maybe the tach way off?

 

Snap On shows the gear it is in, TC locked up, and other data such as speed and rpm. Everything matches instrument panel. I can feel it shift each time, and turning off OD swithc, it drops gears and rpm increases.

 

For reference data point --

@65 mph

OD off = ~2700 rpm
OD on = ~1900 rpm

I think you are 1000ish high, 2200 rather than 3200. lol

 

i think your OD is not engaged or else your speedo is way way off.

i think your scanner will only show you what the pcm has instructed the trans to do. the trans may or may not react, but you should be able to observe a significant rpm drop in response to the transmission command.

you should get about a 500 rpm drop on OD shift, and then another 300 on TC lock. the sequence of these two can vary, based on transmission shift pattern in the pcm. (old vs new, superchips or not).

at 55 with OD engaged and TC lock and with speedo corrected, i turn 1500 rpm.
at 70, i turn about 2000-2200.

 

I have a 373 rear end 265 tires and barely touch 2g at 70 I can hit 90 around 3g