Any Fix for the Awful Rev Hang?

[ShadowsPapa]

I'm running 32s though and will never go larger. I'd humor gears to make reverse better for backing trailers though. I don't know why they think we need to go 45 mph in reverse.

Got that right, but that dates back to the T4 and T5. Reverse in those things is like going backwards at 45 mph. I turn my car around to leave the driveway, there's no way to back it up that hill and not launch across the road into the ditch at the end of the driveway.


The "rev hang" again is not a fault or problem or mistake or terrible engineering - it's emissions.
Ask the Ford guys............. they keep talking about it like it's rotten engineering and the engineers are all idiots and why does my Mustang do this it's really stupid and all that. Guess even Ford drivers are better engineers than real engineers.
Since it's not broken, this thread has a bad title - there's no fix as a fix is for something that's actually broken.
This isn't broken, some people just don't understand it and don't like it.

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[vettred84]

automatic does it too! if you take off fast and let off gas it hangs up in gear and wont shift right away. dealer says its emission system doing its job.

 

[TwelveGaugeSage]

automatic does it too! if you take off fast and let off gas it hangs up in gear and wont shift right away. dealer says its emission system doing its job.

Indeed! I suppose it is just a part of life that needs adjusting to. I guess if it really helps with emissions it's not such a bad thing. It only bothers me occasionally now.

 

[ShadowsPapa]

Indeed! I suppose it is just a part of life that needs adjusting to. I guess if it really helps with emissions it's not such a bad thing. It only bothers me occasionally now.

You'll get used to it.
I'm sure I've posted this before - but in 1994 the same thing was done - I put a 4.0 in my SX4 - complete with the entire PCM and PDC systems and merged all controls and wiring into my car's wiring.
The engine came from an automatic Grand Cherokee.
My car is a stick - Borg Warner T5 5 speed.
I have noticed that when I depress the clutch and downshift for a stop, if I go to neutral or hold the clutch near the end of my stopping, the engine RPM stays up around 1200 or so until I come to a complete stop.
That seems to be exactly what's going on with these, and yet it appears people see this as a new thing?
It was happening in 1994, engine RPM stayed up until vehicle came to a complete stop.
It's emissions and has been around since at least 1994, likely earlier because the system I put in my car was the same as what Jeep used starting at least 92.

 

[MyJeepShawn]

I noticed on mine today that the rev hang was kicking in when the motor was cold. It was in the teens this morning. The revvs were hanging around 1500-2k rpm’s. Depending on how fast I was coasting. It was on,y until the engine started warming up then then the hang went away.

Didn’t really mind at all. Actually made it easier starting from a stop. Could also start out in 2nd at a 5mph roll.

 

[STLMike]

Fixed mine by selling it and buying an auto. Much happier

Same. Rev hang is atrocious in the 6 speed. If I go from my MGB or my C6 to my former JT it bothered me a lot.

 

[Montana_Wildcat]

I've now noticed that I can drive around in 2nd without my foot on the gas at all. She'll just keep pulling on her own until I brake or shift.

 

[MountainDave]

Just got our Gladiator on Friday with 11 miles and after a 200 mile trip, I got the hang of it. That rev hang was weird to me so thank goodness for this forum to find it's a real thing. It's like going to the slipper clutches when they came out in 2013 on my Gixxer. Slight change to driving. Still super annoying.

 

[Rusty PW]

I got rid of the rev hang in my 370Z. Through a tune and going from a 30lb flywheel to a 17 lbs flywheel. Don't think anyone is willing to do this.

 

[jonsheritahe04]

Got rid of it as well on my Mojave….traded for a Rubi auto this week

 

[Geoarch]

Cripes! The Pentastar hooked up to the manual trans has one helluva rev hang going on. I'm sure it is in there to keep the cats working when you let off the gas, but dang is it obnoxious. I tried searching the forum for this issue, but couldn't find much. Do people just don't notice it? Am I being overly dramatic?

Tacoma has that too. There is a fix for that on the Tacoma, but I never did it. I believe Toyota said it was for something about mileage, but no one believes it.

 

[NachoRuby]

Tacoma has that too. There is a fix for that on the Tacoma, but I never did it. I believe Toyota said it was for something about mileage, but no one believes it.

It is for emissions. It's for NOx controls. It is on pretty much all manuals being manufactured these days. The only way to get rid of it completely is with a tune, although I haven't noticed it in a long while on the jeep. It helps that the JT was not my first vehicle with rev hang though, so I'm used to it. It's been on every manual I've owned since my '08 VW rabbit.

https://www.carthrottle.com/post/rev-hang-explained-and-why-petrolheads-hate-it/

https://www.autoweek.com/news/techn...revs-slowly-on-purpose-to-curb-nox-emissions/


https://www.motor1.com/news/448273/vw-golf-manual-rev-hang/

https://forums.nasioc.com/forums/showthread.php?t=2920517

 

[u-joint]

A little late to the party...

We have a '16 jku with manual, and it has rev hang, so I think your '13 will too. Does that one have the 3.6 or the 3.8? I'm not sure exactly when it became a thing on JKs. But I know all the '08 and up models of any brand I've owned have it. Honestly, the biggest thing you'll have to get used to will be the soft clutch feel, and the long third gear. Others will disagree, but IMO, neither is bad, but they take some getting used to. I do think a pedal tuner is a must do, though. (Idrive, ultimate 9, pedal commander, hikeit, etc).

Yes, my '08 JK (with the 3.8L) & 6-speed manual also did this.

On the JK line you had;

* the 3.8L with the old interior from 2007 to 2010.
* the 3.8L with the new interior in 2011
* the 3.6L with the new interior from 2012 onwards

And yes, the reverse position on the JK is stupid.

Beyond stupid - I was always worried I'd (try to) accidently slam it in reverse when I was shooting for 6th.

My bet is that it's emissions related.

It's 100% emissions related.

 

[ShadowsPapa]

Tacoma has that too. There is a fix for that on the Tacoma, but I never did it. I believe Toyota said it was for something about mileage, but no one believes it.

"Fix" - that implies it's a problem. It's not. It's on purpose. It's not a "rev hang", it's not a "mistake" and it's not a "problem" or "Broken".
It's emissions.
I and others have said that several times - it even existed in 1990s vehicles.

 

[Geoarch]

"Fix" - that implies it's a problem. It's not. It's on purpose. It's not a "rev hang", it's not a "mistake" and it's not a "problem" or "Broken".
It's emissions.
I and others have said that several times - it even existed in 1990s vehicles.

Yes, Toyota said the same.

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