Well I don't blame jeep for puttin a stronger tranny in the 6.1L. I mean the srt8 is meant to be quick and most drivers will be runnin it hard. The 545 in the 1500 is not meant to be beat on, the truck isn't a racecr. but havingsaid taht I agree hank that the 545 is not really a"good" tranny. it's ok. but I agree if I ever bought a hemi with thattransmision i'd plan on rebuilding it at some point in time. or outright replacing it.is the six speed an allison tranny thats behind the cummins? I didn't know that but I don't blame them for doin it.

 

hank, here's a little info and also 2 hydraulic schematics of the difference between 2nd gear and 2nd prime:

The 45RFE/545RFE offers full electronic control of all automatic up and downshifts, and features realtime adaptive closed-loop shift and pressure control. Electronic shift and torque converter clutch controls help protect the transmission from damage due to high temperatures, which can occur under severe operating conditions. By altering shift schedules, line pressure, and converter clutch control, these controls reduce heat generation and increase transmission cooling.

To help reduce efficiency-robbing parasitic losses, the transmissions includes a dual-stage transmission fluid pump with electronic output pressure control. Under most driving conditions, pump output pressure greatly exceeds that which is needed to keep the

clutches applied. The 45RFE/545RFE pump-pressure control system monitors input torque and adjusts the pump pressure accordingly. The primary stage of the pump works continuously; the second stage is bypassed when demand is low. The control system

also monitors input and output speed and, if incipient clutch slip is observed, the pressure control solenoid duty cycle is varied, increasing pressure in proportion to demand.

A high-travel torque converter damper assembly allows earlier torque converter clutch engagement to reduce slippage. Needle-type thrust bearings reduce internal friction. The 45RFE/545RFE is packaged in a one-piece die-cast aluminum case. To reduce NVH,

the case has high lateral, vertical and torsional stiffness. It is also designed to maximize the benefit of the structural dust cover that connects the bottom of the bell housing to the engine bedplate, enhancing overall power train stiffness. Dual filters protect the

pump and other components. A pump return filter is added to the customary main sump filter. Independent lubrication and cooler circuits assure ample pressure for normal transmission operation even if the cooler is obstructed or the fluid cannot flow due

to extremely low temperatures. The hydraulic control system design (without electronic assist) provides the transmission with PARK,

REVERSE, NEUTRAL, SECOND, and THIRD gears, based solely on driver shift lever selection. This design allows the vehicle to be driven (in “limp-in” mode) in the event of a electronic control system failure, or a situation that the Transmission Control Module (TCM) recognizes as potentially damaging to the transmission.

The TCM also performs certain self-diagnostic functions and provides comprehensive information (sensor data, DTC’s, etc.) which is helpful in prope diagnosis and repair. This information can be viewed with the DRB

[IMG]local://upfiles/20353/E42EF3FB01704B8B9DCF8D2FC90ECC8B.jpg[/IMG]

[IMG]local://upfiles/20353/4A2FCD1F73554607BEB14950988B0153.jpg[/IMG]

 

this transmission confuses the hell out of me. Its really just a dressed up 3 speed. two second gears and two overdrives....geez I didnt know how complicated this tranny was haha.

 

Yeah, no kidding. Cracks me up that with the tow/haul button pressed , you still get an overdrive. Honestly, when I researched modern Dodges, the tranny was the only consistent thing that popped up as being weak.

 

I have a 09 ram with the diablo predator yesterday I made it downshift and it jerked and paused until it upshifted I was told it could be the tune but why all of a sudden can anyone tell me if it's permanent damage or if they ever experienced this problem

 

Sorry to bring a post back from ten years ago but there is quite a bit of misinformation here! The 545RFE is not at all related to the 42RE, 46RE, 47RE etc. The RE (rear wheel drive, electronically controlled) transmissions were all based on their older hydraulically controlled counterparts which didn�t have governor pressure sensors or transducers (42RH, 46RH for rear wheel drive, hydraulically controlled). Those hydraulically controlled transmissions were based on the old three speed 904 & 727 transmissions from way back. The fourth gear on the RE and RH transmission is a result of an overdrive unit added on the rear of the transmission. The RFE (rear wheel drive, fully electronic) was a brand new design that got rid of the TV cable which changed transmission pressures based on throttle position. It was introduced in the Jeep Grand Cherokee behind the 4.7L v8 as a four speed (three underdriven gears and one overdriven, just like the 42RE, 46RE, 47RE and almost every other four speed transmission out there) except the rfe has a 2nd �prime�, an alternate second gear with a slightly higher gear ratio for downshifts at higher speeds. 2nd prime is not as weak as it�s made out to be. If the transmission is maintained per your owners manual and properly loaded (don�t exceed tow rating, don�t drive like a yahoo while towing) and has a stock engine in front of it, it will last more than 200k. I�ve got one of my own behind my 225k mile �06 5.7L Grand Cherokee which is cammed with headers and regularly abused on the highway. The 545RFE was soon updated in 2002 to apply a different group of solenoids to allow it to use the three planetary gearsets to make a second overdrive or 5th gear that dropped the rpms by about 200 from 4th for better fuel economy on the highway. This update was purely software. A 45RFE is mechanically identical to a 545RFE. Also, the only difference between the 545 and the 65RFE is that the 2011+ software allows 2nd prime to be used sequentially when up shifting with the autostick feature. When not in autostick it is still just a regular 545RFE. This is why it has been referred to as a multi speed automatic.



ALSO, the 6.7L Cummins does not use an Allison trans. Never has in a dodge application. Dodge comes with the 68RFE and later the more heavy duty Aisin AS69RC which has a lower first gear and PTO ability. The 68RFE is just a 545RFE with upgraded internals and slightly lower gear ratios. They are great transmissions when properly maintained and get even better with a bit of tuning.

 

Ten years? Really? Not to mention the original post goes back three years past that....most of these people aren't here anymore.

 

 

Good info nonetheless!

 

Not sure if agreeing or not....