2006 4.0 42RLE rev limit?

TJUNLIMITED211

TJUNLIMITED211

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Nov 26, 2018
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Georgia
Recently went with 5.13 gears. 33” ko2s. Was hoping for much better performance to tame the deep OD but I’ve noticed it still kicks in at 40mph with a light pedal and neuters this pig down to 1200rpm. When I gas it to power through the drop the rev limiter activates at 3200rpm way below red line.

I do have a check eng light for crankshaft sensor maybe this affects it?

Any experience/input would be appreciated.
 
Don't count on it.

Even with the 42RLE and 5.38 gears in mine, the OD still comes on unnecessarily quite often.

This is normal, and there's absolutely nothing you can do about it. It's a shitty transmission to begin with and that .69 OD gear is the cause of all this.

It's a bit better with gears, but will never be perfect.

Anyways, your issue is more than likely related to your bad sensor. Replace it with a genuine OE Mopar sensor (otherwise your check engine light won't go away most likely) and I'll bet that fixes it.
 
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There's no rev limiter that's going to limit its rpm well below redline like your 3200 rpms. There's something else going on that is limiting it to 3200 rpms. The only time I had my engine revs limited was when my main catalytic converter very suddenly clogged so badly it would barely pass the engine exhaust.
 
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Jerry, have you or someone you know tried the shift tables available on HP Tuners? I recently purchased HP Tuners and I haven't registered it to my backup PCM yet, ( a want to get a few more miles on the FS1 reman unit before spending the credits).

Anyway, there is a shift table with shift activities 1-2,2-3,3-4 and inputs scheduled as revolutions. I believe this is transmission output shaft revolutions. I'm curious if adjusting the value higher would delay the 3-4 shift.

Chris, I think you have HP as well - ever experiment with this?
 
pagrey said:
Really? Yes, this is your problem.
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Chris said:
Don't count on it.

Even with the 42RLE and 5.38 gears in mine, the OD still comes on unnecessarily quite often.

This is normal, and there's absolutely nothing you can do about it. It's a shitty transmission to begin with and that .69 OD gear is the cause of all this.

It's a bit better with gears, but will never be perfect.

Anyways, your issue is more than likely related to your bad sensor. Replace it with a genuine OE Mopar sensor (otherwise your check engine light won't go away most likely) and I'll bet that fixes it.
Click to expand...
Thanks Chris. That’s my next move. I saw your write up on it I’ll reference it. Good lookin out.
 
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Jerry Bransford said:
There's no rev limiter that's going to limit its rpm well below redline like your 3200 rpms. There's something else going on that is limiting it to 3200 rpms. The only time I had my engine revs limited was when my main catalytic converter very suddenly clogged so badly it would barely pass the engine exhaust.
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I’ll check that and swap the crank sensor. Thanks Jerry.
 
Juggernaut said:
Jerry, have you or someone you know tried the shift tables available on HP Tuners?
Click to expand...
Even if you changed when it shifted to the next gear, you're still faced with the ratios set by the sun and planetary gears inside the transmission. Eventually it's going to shift into Overdrive no matter what.
 
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Jerry Bransford said:
Even if you changed when it shifted to the next gear, you're still faced with the ratios set by the sun and planetary gears inside the transmission. Eventually it's going to shift into Overdrive no matter what.
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That's absolutely right. Once in overdrive the engine rpm will ultimately be what the gear ratios and tranny ratios dictate. I'm hoping that while I can't change the mechanical ratios of the tranny, and I'm almost maxed out with gears in my Dana 30 front, if I could change this input, it could hold 3rd longer and also change the rpm point where it drops out of overdrive and back to third. Maybe a small improvement in drivability could be had.
 
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Your profile is still not completed so what tire size are you running and is your TJ a Rubicon or a standard TJ or Unlimited? A standard TJ can get as low as 5.13 gearing and a Rubicon can go to 5.38.
 
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Sorry about that - I have it filled out under the "about" portion of my profile. Maybe it's not displaying properly? I'm running the dreaded 35's, 42rle with 4.88 combination. My Dana 44 is rear only now. I think you used to run this combo so you know my pain! Should have gone with 5.13 but that pinion gear looks so small!
 
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Juggernaut said:
Sorry about that - I have it filled out under the "about" portion of my profile. Maybe it's not displaying properly? I'm running the dreaded 35's, 42rle with 4.88 combination. My Dana 44 is rear only now. I think you used to run this combo so you know my pain! Should have gone with 5.13 but that pinion gear looks so small!
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I know that combination well, my present TJ came with that combination. You should have gone for the 5.13, the pinion gear is fine and in fact is the same size used for 5.38. I've been running 5.38 for a little over a year now and that ratios is purely bitchin' with 35's and the 42RLE.
 
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