Transmission hanging in 3rd

[Mike49321]

Just bought my first half ton ram, 5.7. I believe it has the 545rfe transmission. Awesome truck so far. I have already noticed that it seems to shift through first and second perfectly and then it hangs in 3rd at light throttle until about 45-50mph and then shifts, and goes through the rest of the shifts to o.d.

the seller I bought it from has paperwork of truck getting stuck in 4th gear and having the solenoids replaced. Could the 3-4 solenoid be going bad? Again?

Thanks in advance!

also, anyone have a 3rd gen tuner they’d like to sell? Looking to turn off mds as I don’t care for it.

 

[Bloody_Knuckles]

Yes, pretty easy to change. Just messy.

 

[Fast69Mopar]

Is the check engine light on or has it been on lately?

If the 1-2 & 2-3 upshift are normal but stays in 3rd longer there could be an issue with the solenoids.

1st gear uses the UD & L/R clutches
2nd gear uses the UD & 2C clutches
3rd gear uses the UD & OD clutches

For the 3-4 upshift to occur the trans turns off the UD clutch and applies the 4C clutch to obtain 4th gear. If there is abnormal or excessive clutch wear or a leaking seal in the 4C clutch, it can delay the 3-4 upshift while it builds enough fluid pressure to apply the clutch.

A quick look at the CVI's, or Clutch Volume Index, would tell us if the 4C clutch is requiring more than normal fluid volume to apply the clutch. A scan tool is necessary to view the Trans CVI's.

 

[Mike49321]

No lights whatsoever


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[Mike49321]

I should also add that if I slightly let off the gas it will shift to 4th and continue to 5 and od with no problems or abnormalities


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[Mike49321]

Here is a video. Don’t pay attention to me. Apparently counting was tough...


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[Fast69Mopar]

Okay. Thanks for the video. The 545RFE programming can feel weird. The 3-4 upshift can feel like a delayed shift. The PCM seems to want to protect the 4C clutch engagement because 4th and 5th gear are one of the weak points in the RFE transmission. There are two overdrive ratios. 4th & 5th ore both overdrive ratios. The PCM receives inputs from several different sensors to determine when to shift.

Here is a test that I want you to try and get on video.

Start from a dead stop. Get to a location where you can accelerate normally from 0-70mph.

Take a video of the tach so I can see each upshift to 70mph.

 

[Mike49321]

Ok, will do after work. Light throttle? Medium? Heavy? Hammer down?


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[Mike49321]

Normal, never mind. Lol


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[Mike49321]

 

[Mike49321]

Here is a little heavier acceleration. I don’t know. I barely driven it since I got it. Maybe just took some getting used to? I have been driving a 5 speed standard for a few years lol

 

[Fast69Mopar]

Here is a little heavier acceleration. I don’t know. I barely driven it since I got it. Maybe just took some getting used to? I have been driving a 5 speed standard for a few years lol

After watching the last video it appears to shift normally and exactly like mine. One thing I want to see is the CVI's, or Clutch Volume Index. This would tell us if we have a clutch that is requiring more fluid to apply the clutch. A good aftermarket scan tool would be able to show us the CVI's. Something like a Snap-On Modis, Solus or Verus or even an OTC Genesis or Mac Determinator.

See if you can find a local transmission shop to do a free diagnostic and connect their scan tool to your truck. Ask them to look at and record the CVI's for you.

 

[Lilkenny99]

That’s normal these trucks were made to stick in 3rd as much as possible. You’ll foot well eventually learn the trans.

 

[Mike49321]

Yeah, I’m getting used to it. Never owned a dodge before. So far it is awesome.

towed a 14’ trailer the other day helping my girlfriend move. I just put it in tow haul instead of normal drive and got a half mpg better than without the trailer and in normal drive with mds

I need to find a tuner so I can turn the mds off. Lol. I jut don’t want to pay the $300+

 

[Fast69Mopar]

Yeah, I’m getting used to it. Never owned a dodge before. So far it is awesome.

towed a 14’ trailer the other day helping my girlfriend move. I just put it in tow haul instead of normal drive and got a half mpg better than without the trailer and in normal drive with mds

I need to find a tuner so I can turn the mds off. Lol. I jut don’t want to pay the $300+

When you press the button on the shifter to activate Tow/Haul Mode the PCM disables MDS.

The biggest difference while driving in Tow/Haul Mode comes from different shift points and it locks out 5th gear. The top gear will be 4th gear with the torque converter clutch engaged. If you do some testing on the interstate to see what the RPM difference is you will see it's a few hundred RPM. If you don't drive at a fast cruise, which I don't, your mileage may not be negatively affected. When I drive one of my
MDS-capable trucks, I can run in Tow/Haul Mode at 65mph and keep the same fuel economy of just slightly better.

When you accelerate from a stop while in Town/Haul Mode the trans will shift like this...

1st - 2nd - 3rd and then engage the torque converter clutch, then shift to 4th and re-engage the converter clutch.

 

[Mike49321]

Correct. That is exactly how it shifts in tow haul. Tow haul would be 100% for me if 3rd wasn’t dragged out so much lol