Manual Transmission - Issues shifting into 1st & Reverse (Compilation thread)

[gek]

Mine does perfectly smooth shifting once in blue moon too, its part of the problem, make it make sense. Your case, if some critical thinking applied, support that most of the suggestion stated in the history of this thread are complete braindead nonsense.

Most of this thread is speculation and a community trying to come up with ideas when one thing or another fails to fix the issue. Desperation will sometimes lead to a hail mary attempt, or in this case several.

I, for one, would rather those attempts be documented in the off chance that they work or lead someone to an idea or a solution.

As of now there is no end all be all solution, what intermittently works for some has not worked for others. What others experience is also not always the same as others. There are many symptoms and it is possible there isn't one single solution that works for all of them.

We understand your frustration, many of us have been there and back and then been again, only to get so frustrated that we traded our beloved Jeeps for autos or something else entirely.

We all want a solution as much as you do. However, your complaining about this thread and past attempts without offering any suggestions or solutions of your own is only adding to the "braindead nonsense".

If you come up with an idea of or make an attempt at a possible solution please share and/or let us know the results.

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[_olllllllo_]

I agree that 4.88s/35s is the optimal combo with the 6MT, but not because the OEM considers it optimal. Remember, this is the same OEM that put this garbage clutch in the first place and stills offer 3.45s as the base gearing for the 6MT.

5.13s on 37s would be about equivalent to 4.88s on 35s. The simple math is, the % increase in tire diameter should be equal to the % increase in the numerical gear ratio to give the same performance.

IMO, there are 3 gear ratios for a given tire size that are considered "reasonable." You have the optimal gear ratio, one step numerically lower for economy, and one step numerically higher for performance. Anything outside of those 3 I would consider extreme.

IMO, 5.13s would be the optimal ratio for 37s, 4.88s would be the economy, and 5.38s would be the performance. Normally, I like to go for the economy ratio for a DD, but considering the high 6th gear, wide spacing between the lower gears, and lightweight flywheel, I wouldn't settle for the economy gears on the JL. For me, I plan to go with the optimal ratio.

I went with 5.13s even though I was on 35s because I knew I was going to end up on 37s. Just didn't expect to get 77,000 miles out of my 35 KO2s.

 

[Toycrusher]

I went with 5.13s even though I was on 35s because I knew I was going to end up on 37s. Just didn't expect to get 77,000 miles out of my 35 KO2s.

I have 7 yrs and about the same number of miles on my 37 KO2s. They aren't the best at anything but they are shockingly good at just about everything

 

[GabeBoyTheGreat]

I know this is not a perfect solution, but I highly recommend that anyone who is displeased with the OEM clutch look into getting a engine tune for the 3.6l. There is a forum member offering tunes under this thread: https://www.jlwranglerforums.com/fo...g-all-18-26-jl-3-6-non-etorque-models.164496/

There are several improvements that this tune offers. I encourage you to read the tread, but the one improvement that I feel pertains to this thread is improved resistance to stalling. I am not sure exactly why the tune helps, but my 2025 JLU is less prone to stalling after getting the tune done. Others have made similar comments (see the linked thread). The engine definitely runs better in the low-end RPM range, and my guess is this helps prevent the engine from stalling when the load suddenly changes (i.e. letting the clutch out).

I won't say it is a night/day difference. The OEM clutch is still a weak point, but the tune makes it just a little more forgiving. You will still stall if you let the clutch out too quickly with 0 throttle input, but slow, controlled clutch engagement seems to work a little better than before, maybe 20-30% (it is really difficult to gauge/measure).

Of course, I usually am always giving it a little bit of throttle when engaging the clutch, and when I am giving it throttle, it really seems difficult to stall unless I am actually trying to make it stall, whereas before it felt like a total crapshoot. That is why on the stock tune, I had a tendency to overrev the engine a little to prevent from stalling; it doesn't feel like I have to do that anymore.

Also, overall engine response in the low-end RPM range is improved, so starting off in 1st gear is so much smoother and less jerky. I also haven't noticed that low-speed bucking phenomenon with the new tune that occurs sometimes with the old tune.

All in, you are looking at just around $1,300 for the tune itself and everything that is required to get the tune uploaded. I can honestly say, even if the OEM clutch wasn't trash, the tune is absolutely 100% worth the money. The improvement in stall resistance is just a bonus. It sounds like these aftermarket clutches will cost at least twice that much and is kind of a crapshoot whether or not you will have problems down the road. Personally, I don't see any downsides with the tune, only improvements across the board.

I just wanted to say that I had @bmpcamry09 increase my idle RPM by 200 RPM, and boy, that made a HUGE difference in terms of driveability with the stock clutch! I feel that it really offsets the lightweight flywheel.

Again, this is not a perfect solution, but if you are not pleased with the performance of the stock clutch but don't want to risk the issues of the aftermarket clutch, I highly recommend you try the tuning option.

For more details specifically regarding the increase in idle RPM, please check out my thread here: https://www.jlwranglerforums.com/fo...ity-of-the-6mt-by-increasing-idle-rpm.169417/

 

[Reflektr]

I just wanted to say that I had @bmpcamry09 increase my idle RPM by 200 RPM, and boy, that made a HUGE difference in terms of driveability with the stock clutch! I feel that it really offsets the lightweight flywheel.

Again, this is not a perfect solution, but if you are not pleased with the performance of the stock clutch but don't want to risk the issues of the aftermarket clutch, I highly recommend you try the tuning option.

For more details specifically regarding the increase in idle RPM, please check out my thread here: https://www.jlwranglerforums.com/fo...ity-of-the-6mt-by-increasing-idle-rpm.169417/

This does make some sense because mine seems to shift a little smoother when the rpm’s are a touch higher. Sometimes. Or if you double clutch it and shift in “slow-motion” it smooths it out too. You don’t get that “Whack” at the transfer case

 

[Reflektr]

Mine does perfectly smooth shifting once in blue moon too, its part of the problem, make it make sense. Your case, if some critical thinking applied, support that most of the suggestion stated in the history of this thread are complete braindead nonsense.

Dude. People are already feeling bad enough about their $45k paperweights. Ain’t no need to add insult to injury from another opinionated (troll likely getting paid) used-tampon on the internet.

 

[mudpup]

I'm at 10k on my hydraulic throw-out and agree it is still fantastic compared to OEM (and ACT).

I’m at 21,000miles with the CF and it’s been really perfect.
That said I’m trading in with Carvana for a 180-degree change.

Pick up and delivered to my house next Wednesday.
22 Black 3.6 to new 26 Hydro Blue with the auto and 2.0.
Just like that and looking forward to some color with better mpg.

 

[OldGuyNewJeep]

This has to be in my head, but I swear I haven't had any resistance shifting to 1st since replacing this wiring harness: https://www.jlwranglerforums.com/fo...ce-axle-locker-on-and-off.100722/post-3485081

I know. The symptoms in this thread are mechanical, not electrical. I can't explain it.

Only other change is teaching another of my kids to drive stick. Typical excessive slippage during launch, stalls, etc. for a newbie. Broke in my newish setup for me?

I don't know. Also hot, humid weather?

All I can say is my Jeep is driving better than ever. My eye no longer twitches 10x a trip because of "Ding! Service axle locker system" interrupting my music, and that is certainly a huge relief, but the clutch and transmission feel soooo smooth. I've been zipping all over town like a teenager because the thing is so damn fun to drive right now.

That's all. I just jinxed it. Carry on.

 

[GabeBoyTheGreat]

This has to be in my head, but I swear I haven't had any resistance shifting to 1st since replacing this wiring harness: https://www.jlwranglerforums.com/fo...ce-axle-locker-on-and-off.100722/post-3485081

I know. The symptoms in this thread are mechanical, not electrical. I can't explain it.

Only other change is teaching another of my kids to drive stick. Typical excessive slippage during launch, stalls, etc. for a newbie. Broke in my newish setup for me?

I don't know. Also hot, humid weather?

All I can say is my Jeep is driving better than ever. My eye no longer twitches 10x a trip because of "Ding! Service axle locker system" interrupting my music, and that is certainly a huge relief, but the clutch and transmission feel soooo smooth. I've been zipping all over town like a teenager because the thing is so damn fun to drive right now.

That's all. I just jinxed it. Carry on.

Shot in the dark, but is it possible that slipping the clutch is actually helping? I would believe that over replacing the wiring harness.

My thought process is that perhaps there is clutch material that builds up over time, which causes the flywheel to grip the clutch disc. That would sort of fit in with @Toycrusher's theory that lack of resistance from the transmission side is causing the disc to not break free from the flywheel. In other words, perhaps it is a two-fold problem: clutch material buildup increasing the grip of the flywheel and not enough resistance in the transmission to release the grip?

Then perhaps by slipping the clutch periodically, this sort of "cleans" out the clutch material buildup? That could explain why the aftermarket clutches fail after about 10k miles; enough time for the clutch material to build up. Then the symptoms get progressively worse over time as the material builds up more.

The aftermarket clutches are less prone to slipping since the flywheels have more mass, thus requiring less throttle to get going. The lightweight OEM clutch will inherently slip more because it requires more throttle, which could be why the failures are less prevalent with the OEM clutch.

Like I said, shot in the dark, but it makes more sense than replacing a wiring harness.

 

[basemodel]

I updated on my thread, but I’ll post here as well. I have 4000 miles on a McLeod clutch with the internal throw out bearing and had similar issues to most people after a couple of days of driving. It was tough to get into first/ reverse and would occasionally roll forward when I started it in gear.

I swapped out the ATF in the gearbox and transfer case for gear lube, and it has almost entirely cleared up the issue! I can count on one hand the number of times it has been a little firm going into first or reverse in the past week. I’ve had zero lock out issues since I switched the fluid in the past week. Shifts are less notchy as well. My wife drove it in city traffic for about an hour without issue, so it passed the wife test too!

The clutch feels how it should have from the factory, and I’m over the moon about it!

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