Maximum RPM for long highway driving with 4.0

[DuneSeeker]

I have a 2005 TJ Sport with 3.73 stock gears and 32" tires. Which actually measure 31.5".
6 Speed Manual Transmission
I might go to 33s one day but Im quite happy on my 32s for now.

I'm looking at regearing to 4.56 or 4.88 but my highway RPMs at 75mph would be 3000 (4.56) or 3300 (4.88) according to the Grimm Jeep Calculator.

Its not my daily driver but I do have to drive 1-3 hours on the highway to get into the deserts where I take her on offroad trips.

My question is "What is the maximum safe RPM for the 4.0L engine to be running at extended periods for (1-3 hours)"

3000 RPM feels a bit high for extended periods of time but I've heard the 4.0L loves high revving but I'm not sure if that's for extended periods of time given how heavy she is and the heat that would be produced at those RPMs for a long period of time.

Your opinions would be much appreciated. Thanks.

 

[Chris]

3000 RPM is not a high RPM. I sit with mine at 3000 RPMs for hours on the highway and haven't had an issue.

I wouldn't be even the slightest bit concerned over 3000 RPMs for long periods of time.

 

[Jerry Bransford]

Such rpms are an absolute non-issue for the engine. My last TJ regularly ran those rpms on the highway during long trips.

 

[PurpleTJAZ]

My set up runs 3000 rpm at 65 mph and I have run the for several hours in the Arizona heat with no problem. The down side is fuel mileage at 3000 rpm is not great………

 

[DuneSeeker]

Thanks - thats great to know.

 

[chimmike]

TBH it's not lugging the engine at that rpm. The only downside is the volume.