I have a 2011. I'm in some other threads talking about the difference between 5th and OD, but all the documentation says that this is a 5 spd transmission... So OD would be a 6th phantom gear?

If you drop the selector to 5th, it drops a gear? if you drop it again it goes to 4th, then 3rd, then 2nd, then 1st, so I'm feeling 5 changes, which suggests 6 gears, so how is it a 5 spd transmission?

whats going on, and what am I missing?

 

Our 5 speed tranny's have two second gears, one for normal driving and the other only kicks when the tow/haul selector is engauged for better towing performance. As far as when you drop the slector to 5th gear, I don't think it is dropping down a gear but rather the torque converter is unlocking. When my truck shifts into the top gear at a stable speed I can see the RPM's drop several hundred RPM's as the torque converter locks up. Despite all 5 gears, MDS and economy 3.21 rear ratio, my truck still drinks gas like a drunken sailor.

 

Between this and the cruise control post, I think I get it now. sorry for the confusion, but I appreciate your feedback.

It is the torque converter. I guess its time I figure out how to work an auto tranny, although all the cars I've worked on in the past have been manuals, which make a lot more logical sense. I was getting confused because I was seeing 6 different gear ratios, 6 gears named, felt 6 gears (TC).

so thats why our 5 speeds have 6 speeds plus the torque converter, but only 5 speeds are used in a driving mode, so its called a 5 speed transmission.

I get it now. Thanks ever so much!

 

All vehiucles have a TC(torque converter). It just depends if the torque converter is locked or not. At certain speeds, it locks which increases power transfer as well as mpg's. When it slips, your basically losing power, this is why guys go aftermarket TC's so it locks up more often.
O/D is the final gear ratio's. Since the Ram technically has 2 final gear ratio's, the O/D off locks out 4th and 5th gear. Nothing with the TC changes.
Tow/Haul locks out 5th gear and I'm not sure whether or not it alters anything in the TC as for lock/unlocking?
There is a section in the Owners Maunual that explains some of these features. Not sure where, but it's gotta be there somewhere..lol It might not go into depth and explain anything about the TC.

Chrysler wanted to start calling the 545rfe a 6spd auto trans. That's false. Yeah, it does have 6 gears, but it's only 5 forward gears that the truck shifts through, not 6. So, I would have to accuse them of deceptive advertising at that point. At that point they should just call it a 7spd and include reverse in their calculations...lol
Your trans shifts like this most of the time...1-2-3-4-5 and then on hard throttle downshifts5-4-3-2nd prime-1. A Chrysler Eng did say that 2nd prime is used on upshifts(1-2nd P-3-4) when in tow/haul mode but this seems contradictory of the whole purpose..Never the less, the double gear is called 2nd Prime. It's a weak gear and not a very good one. It's used at speeds between ~30-50mph when you want to step on it and get going. It's a taller gear than the upshift of normal 2nd. This aids in less rpm's racing and neck jerking when downshifting.

 

Actually, for 2012 the Ram gets a 645RFE, which now uses all six gears in sequence for normal driving.

Regards,
Dusty
2010 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 545RFE, 3.92 LSD, dual exhaust, 20” wheels