Any empirical data on engine life if running the 3.6L at >2800RPM for long periods of time?

[Hootbro]

F

First quick check this isnt the 3k rpm I orginally saw, but “low RPM” is extremely vague in every way as factory can have people using 8th going 55 and that gonna be at ~1,500rpm, is that low?

• Change Engine Oil at 4,000 miles (6,500 km) or 350 hours of engine run time if the vehicle is operated in a dusty and off-road environment, or is operated predominately at idle or only very low engine RPM’s. This type of vehicle use is considered Severe Duty

I dont like that they say it, but its mentioned, also the reason we have a two stage pump is for one reason and one reason only, efficiency. Less pressure, less effort, small fuel economy gain. Same story with low oil viscosity (and yes of course, the engine is designed to run on said lower oil viscosities, but thats not the reason the oil viscosity was initially lowered). Ill have to keep looking for the 3k rpm mention though. Ill also add thats a 2020, 21 rewords it but same message, 22-23 omits the statement alltogether, what that means??‍

I think they are more worried about fuel dilution in the oil with extensive idling and low RPM use.

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[MemphisMississipp]

My goal is to stop it gear hunting 7th-8th at 50mph and higher. Yes, re-gearing will make the intermediate gears shorter and I don't need or want that. If the shift from 8th to 7th was more seamless, I would be okay with it downshifting like an automatic is meant to do. But, unlike all the other downshifts, 8 to 7 is not seamless. I'll be on the gas pretty hard trying to maintain speed in 8th. When it finally downshifts to 7th, that much pedal makes it accelerate vs maintaining the same speed. If I could reprogram the transmission, I'd do that instead (but I still think it could use 4.56 vs the factory 4.10).

I got a cat back exhaust now I can hear my downshifts. I combat what your talking about 7 & 8 gears hunting as you say, just shifting manually when I’m n those situations. Usually towing the camper

 

[Badunit]

I signed up today to get 4.56 gears installed. It'll be a few weeks before they get to me. It'll put me at >2000rpm from 63mph on up and will run 2550rpm@80mph.

 

[JerseyMark]

Jeep does put factory 4.88s in the JL Rubicon with the Manual transmission and 33” tires. My wife has that combo in her JLU and it‘s awesome. I wish the Gladiators had a similar factory option. I will say she complained a bit about the really low 1st gear initially, but got used to it. I love driving it and wish they had a factory 4.88 option in the Gladiator.(I have the stock 4.10s in my Mojave)

 

[Badunit]

Thanks for the reply. If the manual is awesome with 4.88 then the automatic should be awesome with 4.56. I hope so because I just had it done yesterday. I have 500 miles of easy driving before I can get on the interstate at the speeds I normally travel to really test it out.

MT high gear is 0.72. AT high gear is 0.67. Equivalent differential gearing for AT would be 4.88*0.67/0.72 = 4.54 so 4.56 is right on the money.

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