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Old 07-15-2013, 12:58 PM   #31
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Quote:
Originally Posted by panthermark View Post

Interesting...
Without seeing it, it is hard to say.

If the Jeep has shifted into 2nd gear, it might take a beat or so to upshift and find the right gear once you are off the skinny pedal....but it should not hang there for too long.

Can you give us a but more history on your Jeep? Which Sport is it (did it come with 29"'s or 32"'s)?

Is the axle ratio 3.73?

Are you on 33's? If so has the speedo been adjusted?
Almost 100% sure on the 3.73 axle, idk what it came with regarding tire size. I am running 33's now but the speedo was corrected.

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Old 07-16-2013, 10:14 AM   #32
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I wish I could help. But I will say that, man, I have 4.10s and I'm hard pressed to get it above 3k rpm. I know it doesn't answer your question....but 4k seems like you are winding the hell outta that thin Can't imagine n getting close to 4k while driving. I get it may take more power with dirent gearing/tires. Just seems really high rpm based on how mine drives.

Btw I hate this effin phone so sorry for the spelling

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Old 07-16-2013, 10:22 AM   #33
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OP, i have a 3.8 liter 2008 automatic. You are referring to wide open throttle, right? Mine continues to accelerate all the way to the redline, but develops less torque past 4000. You've reached peak horsepower/torque at 4000. But it should still accelerate. Under wide open throttle anyway.

Quote:
Originally Posted by redskinswin View Post
Check to make sure you are not in 4 wheel lo. My dad did that on his Chevy recently and had the exact same symptoms. If you are in 4 lo I would not admit it to anyone. He has not and never will live it down.
Seriously? Wouldn't it be kind of obvious as soon as you touched the gas? Have you ever used 4 lo??????? Also, isn't the lever about 6 feet away from 2hi in 4lo?
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Old 07-16-2013, 12:35 PM   #34
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It has to be slipping. Only logical explination. It will especially slip under high load (peak of the power curve, under hard acceleration like your saying) this is only the beginning!
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Old 07-16-2013, 02:28 PM   #35
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Nevermind.

NC
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Old 07-17-2013, 06:45 PM   #36
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The only time I go to 4k rpm is getting on the highway at this one spot. I usually keep it around 3300 when accelerating.

Guess that it could just be slipping because I am working it too hard. My jeep srt8 doesn't seem to mind going over 4k
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Old 07-17-2013, 08:18 PM   #37
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Uhm, if its slipping, you're going to jump in it one day and it's going to refuse to pull out of your driveway. have you checked the fluid level?

why would it be acceptable for it to ever slip?

your transmission is going to fail.
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Old 07-17-2013, 09:31 PM   #38
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Then lets just say I am at its peak power. The fluid levels are fine. Lets forget about all of the slipping business because that just sounds like too much $$$
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Old 07-17-2013, 09:34 PM   #39
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You can be sure that whatever its going to cost you right now is about 10% of what its going to cost you on the day it refuses to move.

Deferring maintenance is never cheaper.
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Old 07-17-2013, 11:54 PM   #40
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I have it regularly maintenanced so there shouldnt be any major problems
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Old 07-17-2013, 11:59 PM   #41
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Quote:
Originally Posted by 123Jato View Post
I have it regularly maintenanced so there shouldnt be any major problems
Uhh... except that there are apparently problems?

Is this thread just a big circle jerk? If you're having it regularly serviced and its doing what you're describing then your mechanic is a chimpanzee.
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Old 07-18-2013, 12:01 AM   #42
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So what exactly is tranny slipping mean?
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Old 07-18-2013, 12:07 AM   #43
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Just as a side note: this hasn't happened to me in a month because I try to take it easy whenever possible on the accelerations. I guess I am so accustomed to the jeepsrt8 that I had the petal to the metal philosophy. The whole thing is strange because if it was the tranny slipping wouldnt it happen more often?
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Old 07-18-2013, 12:07 AM   #44
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Quote:
Originally Posted by Doctorsti View Post
do you mean the tach just pegs itself or that you get no more acceleration after 4000RPM's

If it's that it just feels like it won't accelerate faster after 4000 it's because at 4000 the torque produced by the engine falls off a cliff.
See here:
2012 Jeep Wrangler JK - Trail Test - 4 Wheel Drive Magazine
Great!! Should have waited...( not that i climb mountains
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Old 07-18-2013, 12:12 AM   #45
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It means that your engine is turning one speed and your transmission is moving at another speed.

Basically when you're reaching a certain amount of power, you're overcoming the ability of the transmission to keep up.

Some slip in an auto transmission is normal, but jumping 1000 RPM on a paved road is not normal.

Something is wrong. If it was jumping 1000 RPM because it was shifting, that'd be a different thing, but if its remaining in the same gear and the rpm is just running up to 5k from 4k and there is no change in speed, then something is wrong.

I'm going to make this my last post in this thread, because frankly I feel I'm having my time wasted. And while you might think its funny, I don't.

You asked for help, most of the people here have tried to help you, but your ultimate response seems to be 'whatever'. If you didn't want the help, why ask? right?

Anyhow, take it for service, or don't. Its your truck. I hope you sort it out, or not, depending on whatever it is you actually wanted to accomplish.
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Old 07-18-2013, 03:02 PM   #46
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I am sorry if you feel as though your time is wasted.

You guys explained this very well to me and I really just don't know too much about how the engine/ transmission work. Some say I am at peak power others say it is the tranny slipping. The thought of major transmission work has me worried though which is why I am just hoping that it is just at its peak power curve which would make me go in circles.. And again I think it be slipping more often if there is a problem with the transmission. There is no need to reply back
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Old 07-18-2013, 03:36 PM   #47
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Without seeing a video (or basically driving it), we can't tell what is wrong.

When you say it jumps in RPM's...is it simply shifting down to 2nd gear? That would be normal.

Try this....
Find a deserted spot, put the Jeep in 2nd gear instead of drive, and gun it. Get it up to about 70mph.
If your RPM's jump from 4000 to the redline, something is wrong with your tranny.
If your RPM's continue to rise at the same rate, but you are not accelerating as much as you were (up to 4000 rpms), you are just hitting peak power.

You are missing most of the symptons of a bad torque converter and it would seem unusual for your tranny to slip ONLY at 4000 rpms.

One of the biggest flaws of the 3.8/42RLE tranny was it's lack of passing power....espeicailly in a 2 ton rolling brick.
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Old 07-18-2013, 03:54 PM   #48
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Thanks for the reply, seems like a great way to test it out, I will let you know tomorrow to see how it went.
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Old 07-18-2013, 08:48 PM   #49
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Forgot to mention, i had a slipping tranny once. It started out where itd just take forever to engage into gear when you put it in drive or reverse. got worse and worse. one day it just started slipping so bad itd barely move. i took it up to a local mechanic. Hes like, well you probably need teh transmission rebuilt. I can do it for $1800. But try this stuff first. He handed me a can of Justice Brothers Transmission Cleaner. Told me to put it in the ATF. After about a week of driving, the transmission acted like brand new and never did anything bad again. Always engaged into gear immediately and never slipped again, til the day i sold it. Infact, the guy who bought the car from me blew the engine, transmission still worked fine.

So i'd try that if it was really slipping.
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Old 07-19-2013, 12:58 PM   #50
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Quote:
Originally Posted by panthermark View Post
Without seeing a video (or basically driving it), we can't tell what is wrong.

When you say it jumps in RPM's...is it simply shifting down to 2nd gear? That would be normal.

Try this....
Find a deserted spot, put the Jeep in 2nd gear instead of drive, and gun it. Get it up to about 70mph.
If your RPM's jump from 4000 to the redline, something is wrong with your tranny.
If your RPM's continue to rise at the same rate, but you are not accelerating as much as you were (up to 4000 rpms), you are just hitting peak power.

You are missing most of the symptons of a bad torque converter and it would seem unusual for your tranny to slip ONLY at 4000 rpms.

One of the biggest flaws of the 3.8/42RLE tranny was it's lack of passing power....espeicailly in a 2 ton rolling brick.
I just tried this, brought it up to 4k then I still went nicely to 4.5k just slowed the acceleration a little bit. I guess that solves that. Just probably need to regear.
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Old 07-19-2013, 02:16 PM   #51
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regearing wont change the power band. its not going to be a fast engine.
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Old 07-19-2013, 02:40 PM   #52
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Quote:
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I just tried this, brought it up to 4k then I still went nicely to 4.5k just slowed the acceleration a little bit. I guess that solves that. Just probably need to regear.
Well, at least it is good to know that nothing is wrong with your tranny.

A regear won't get you more power above 4000 rpm's...there is none to be had unless you add a supercharger. A regear will simply run your engine at a higher rpm (relative to a given speed) than it is right now. The problem with the 42RLE is that in 4th gear on the highway, the rpms are too low, so you are below the power band. It is made even worse by going to 33's. At 60mph, you might be turning 1600 rpms. The engine is barely creating enough power to keep your vehicle moving. A regear might bump that up to 2200 or 2300 rpms...where you are producing more power.

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