Need Help Troubleshooting

SLO

Member
I realize that trying to troubleshoot over a forum is near impossible but I wanted to run this by the community for input. I’m having two issues with my Jeep that I think could be related. It’s been in the shop for weeks now and I believe that they are chasing down the wrong rabbit trail.

I “believe” there is some sort of resistance during acceleration. It feels like there isn’t the power/torque/acceleration that it should have. Also, the transmission is getting abnormally hot. I am now wondering if this could be a bad torque converter. I know transmission heat could be caused by a bad torque converter but what about loss of power during acceleration? I’m not noticing any noises, shuddering, slipping, etc that are common with bad torque converters.

Thoughts?
 

wayoflife

Administrator
Staff member
Are you saying that you had more power but now don't? Or, are you saying that you think you should have more power but don't?
 

SLO

Member
Are you saying that you had more power but now don't? Or, are you saying that you think you should have more power but don't?

Eddie, I was intentionally being vague because I didn’t want to start anything on here specific to any vendor or product but the honest, direct answer to your question is the latter. I “think” I should have more power but I don’t. I drove two other builds nearly identical to mine and there is a huge difference *to me*. I’m at the point now that I either figure out what’s going on or I’m selling it. I’m grasping at straws at this point but I’m also kind of on my own to prove there is an issue. I had a buddy suggest checking the torque converter so that’s where I’m at.
 

Sharkey

Word Ninja
Stupid question, but would putting it on a dyno tell you if you are getting the power you should be getting?
 
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wayoflife

Administrator
Staff member
Eddie, I was intentionally being vague because I didn’t want to start anything on here specific to any vendor or product but the honest, direct answer to your question is the latter. I “think” I should have more power but I don’t. I drove two other builds nearly identical to mine and there is a huge difference *to me*. I’m at the point now that I either figure out what’s going on or I’m selling it. I’m grasping at straws at this point but I’m also kind of on my own to prove there is an issue. I had a buddy suggest checking the torque converter so that’s where I’m at.

Define nearly identical?

Also, you have an LS, have you tried having the tune changed? You’d be surprised at what a difference it can make.


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SLO

Member
Define nearly identical?

The two I drove were JKU’s with a 6.2 LS, 6L80, beadlocks, 40’s, D60’s, steel bumpers, winch and various levels of armor. In other words, they all had same/similar engines and transmissions, same size wheels and tires, and were all heavy (guessing around 6,000 lbs). They both had 5.38 gears. Only difference was that I had 4.88. I changed to 5.38 and mine still aren’t on par with the other 2.

Also, you have an LS, have you tried having the tune changed? You’d be surprised at what a difference it can make.


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I have had John at Overland tweak it multiple times. It definitely helped throttle response but still felt like there is resistance...or something is off. The tune is actually what was being blamed for the heat and other issues I’m having so it was returned to the stock tune. Still getting too hot and feeling underpowered.
 
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Snboarder113

Active Member
The two I drove were JKU’s with a 6.2 LS, 6L80, beadlocks, 40’s, D60’s, steel bumpers, winch and various levels of armor. In other words, they all had same/similar engines and transmissions, same size wheels and tires, and were all heavy (guessing around 6,000 lbs). They both had 5.38 gears. Only difference was that I had 4.88. I changed to 5.38 and mine still aren’t on par with the other 2.




I have had John at Overland tweak it multiple times. It definitely helped throttle response but still felt like there is resistance...or something is off. The tune is actually what was being blamed for the heat and other issues I’m having so it was returned to the stock tune. Still getting too hot and feeling underpowered.

Have you checked the stupid obvious things? Pull your spark plugs and inspect them. See if it’s running lean or rich. Check af/r with a wideband. Things like that


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SLO

Member
Have you checked the stupid obvious things? Pull your spark plugs and inspect them. See if it’s running lean or rich. Check af/r with a wideband. Things like that


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I need to ask them what all they have checked so far. It’s been at the shop that did the swap for over a month now so I’m not sure exactly what they have and haven’t done.
 

wayoflife

Administrator
Staff member
The two I drove were JKU’s with a 6.2 LS, 6L80, beadlocks, 40’s, D60’s, steel bumpers, winch and various levels of armor. In other words, they all had same/similar engines and transmissions, same size wheels and tires, and were all heavy (guessing around 6,000 lbs). They both had 5.38 gears. Only difference was that I had 4.88. I changed to 5.38 and mine still aren’t on par with the other 2.




I have had John at Overland tweak it multiple times. It definitely helped throttle response but still felt like there is resistance...or something is off. The tune is actually what was being blamed for the heat and other issues I’m having so it was returned to the stock tune. Still getting too hot and feeling underpowered.

What axles are you running and what axles were they running - specifically?

Running hot problems is normal with a V8 and trying to keep it cool isn't easy. There are a LOT of different tunes you can do and some will make a much bigger difference than others. A hot tune can make things run hotter but that just means you need to find more creative ways to keep things cooler.
 

cpefy3

Member
Have you checked the quality/level of your trans fluid? Might not be a bad idea to install an aux trans cooler if you don't already have one. I was having similar issues with my old XJ. It turned out old trans fluid was running excessively hot and was causing the trans solenoids not perform correctly due to overheating. Best of luck tracking it down!!
 

SLO

Member
What axles are you running and what axles were they running - specifically?

Running hot problems is normal with a V8 and trying to keep it cool isn't easy. There are a LOT of different tunes you can do and some will make a much bigger difference than others. A hot tune can make things run hotter but that just means you need to find more creative ways to keep things cooler.

Have you checked the quality/level of your trans fluid? Might not be a bad idea to install an aux trans cooler if you don't already have one. I was having similar issues with my old XJ. It turned out old trans fluid was running excessively hot and was causing the trans solenoids not perform correctly due to overheating. Best of luck tracking it down!!

One was running UD60’s and the other Dynatrac. I’m running Fusion 4x4.

I hear you on the tunes, Eddie. Problem is, going back to a stock tune which is very conservative is still yielding heat issues. And, that is a “proven” tune according to the shop.

This week, they are installing a trans cooler and an oil cooler. I’m confident that they will improve the heat issues. My bigger concern is the perceived lack of power and the possibility there is a bigger issue that is contributing to the transmission getting so hot.
 

cpefy3

Member
Are you positive the transmission is shifting into OD. If not, it will def cause heating issues.
 

wayoflife

Administrator
Staff member
One was running UD60’s and the other Dynatrac. I’m running Fusion 4x4.

I hear you on the tunes, Eddie. Problem is, going back to a stock tune which is very conservative is still yielding heat issues. And, that is a “proven” tune according to the shop.

This week, they are installing a trans cooler and an oil cooler. I’m confident that they will improve the heat issues. My bigger concern is the perceived lack of power and the possibility there is a bigger issue that is contributing to the transmission getting so hot.

Okay, so, different axles use different bearings. Bigger bearings will be stronger but they will also cause more resistance. I have seen where this can make a measurable difference even on a dyno. So, that could be part of what your feeling and why, although the other Jeeps are "similar", they are NOT the same. I should note that UD60 will have the best performance.

Again, the heat issues you're having are just things that need to be addressed outside of a tune. If you have anything in front of your grill, get rid of all of it and it'll make a difference. If you're still seeing heating issues, change out coolers, add coolers, add fans or whatever is necessary to keep things cool. While Moby runs pretty good most of the time, I'd still like to see better cooling as well and so I'm trying a few new things myself. I can report back once they're done and I've had a chance to test them out. Like you, I want more power and will update my tune once I get to a point where I can keep things on the cool side.
 

SLO

Member
Okay, so, different axles use different bearings. Bigger bearings will be stronger but they will also cause more resistance. I have seen where this can make a measurable difference even on a dyno. So, that could be part of what your feeling and why, although the other Jeeps are "similar", they are NOT the same. I should note that UD60 will have the best performance.

Again, the heat issues you're having are just things that need to be addressed outside of a tune. If you have anything in front of your grill, get rid of all of it and it'll make a difference. If you're still seeing heating issues, change out coolers, add coolers, add fans or whatever is necessary to keep things cool. While Moby runs pretty good most of the time, I'd still like to see better cooling as well and so I'm trying a few new things myself. I can report back once they're done and I've had a chance to test them out. Like you, I want more power and will update my tune once I get to a point where I can keep things on the cool side.

Thanks Eddie! I think we are at that point of adding coolers and trying different things out. I think Moby is down at the same place mine has been the last month. They are doing some side-by-side comparisons (I realize they are different) including testing the JL fan. I’m flying down in a couple weeks to check out the progress.
 
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