545RFE 2 PRIME?

[Snake15eyes1998]

I looked through all the threads on here regarding this question. I still don't quite understand this 2nd prime. Can anyone, post a link that really explains this? Or can even explain it themselves?

 

[Tim Garceau]

It’s only used for downshifts. You basically have a 3 speed with overdrive unless custom tuned

 

[Snake15eyes1998]

So if I'm manually shifting my truck into 2nd gear. Its going into 2nd gear? Or 2 prime?

 

[TheEnder]

So if I'm manually shifting my truck into 2nd gear. Its going into 2nd gear? Or 2 prime?

It’s going into second gear on the 545RFE. The only way to shift into 2nd prime from EVIC is if you have the 65RFE, which allows the driver to shift into it manually.


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[HemiLonestar]

Three speed (1:1 is 3rd gear) with two overdrives. Normal upshifting goes 1-2-3-4-5. Normal downshifting is 5-4-3-2-1. Shifting manually into 2nd gets you exactly that, 2nd gear. If you romp on it from 3, 4 or 5, the TCM will kick it down it down to 2P. 2P (1.5:1) has a different ratio than actual 2nd (1.67:1) that's closer to the taller gears, ostensibly so the engine doesn't fall as far out of the power curve. Downside of this is 2P uses the OD clutch set, which are of course the physically weakest in the case. To offset this, the programmed in torque management lowers engine power at the shift. This is why generally the RFE will last and is just fine behind completely stock engines. A soon as you start modifying things for power, it doesn't like it.

It’s going into second gear on the 545RFE. The only way to shift into 2nd prime from EVIC is if you have the 65RFE, which allows the driver to shift into it manually.

Which doesn't apply here because he has a 2006.

 

[Snake15eyes1998]

Thanks guys for helping me understand. I appreciate it. It makes a lot more sense now.