No 5th gear

Here's something I've been considering. Could your clutch be slipping? 3500 rpm is absolutely not normal for 75 mph with any 5 speed unless you are regeared to like 5.13 and 31's which would be insanely low. I don't know who you checked with but 3000 at 65 in 5th and 3500 at 75 is not normal. Whoever told you that is clueless. That RPM for that speed would be more along the lines of a 3-speed auto with 31s and 3.73 or 4.10.

Does the RPM shoot up without you gaining speed ever? The Jeep would feel powerless, not necessarily like it's bogging but more like it just couldn't really do much. I'm not sure if shifting to 4th with a slipping clutch would help or not, but it probably would help because there would be much less force on the clutch required to maintain speed up a hill in 4th gear.

Just something to think about, but the info I'm receiving doesn't add up at all so I'm thinking a slipping clutch with that RPM level you're dealing with.
 
Sorry for the confusion but I was way off. Checked it out this morning when I hit road and at 75-80 I'm only running at 2 RPM's
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Ok then, running 2k at 70 mph on 5th.... that's a different story.... what year is your TJ, they used different trannies throughout the TJ production years, either way you have a standard so this should be less an issue. You are definitely geared a bit in the high side ( or low depending how you look at it, lol). At 70 mph on 5th you should be at least 2300 rpm to be the engine power band, and better fuel millage. I'd say your engine is running fine, especialy if you say in 4th it's fine , except running a bit high rpm for that speed.

When you say you are running 70 mph, is that actual speed via a gps or your speedo? Reason I'm asking is you have bigger tire size so OEM speedometer set up would be off. Good thing about TJ, this is an easy adjustment by changing the plastic gear at the transmission pick up unit, 20 minute job.


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To me it really sounds like you were either having a bad wind day or you were driving in 5th when you should have been in 4th. Your RPM is way too low as it is and if I were you, I would never use 5th in your setup. Looks like you have 3.07 gears and with those 31's, you're lugging the engine big time in 5th.

As far as the fuel filter, TJs have lifetime fuel filters that typically shouldn't ever have to be changed. I'm sure there can be some exceptions to that but I really highly doubt it. If it's the filter, you'd have to drop the tank and take everything back there apart to get to it. I doubt it's the fuel filter.

You're definitely bogging it down in 5th, so for starters, quit using 5th. It won't hurt anything and your mileage will very likely go up from the engine being in a more efficient range.
 
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