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

[andrei]

Hopefully my last update on this issue. Jeep is back to shifting smooth thanks to the great people over at ACT.

Here's the full story but the lesson is everyone check their hydraulics for air. It seems even 2 bubbles worth is enough to throw the Jeep completely out of whack.

https://www.jlwranglerforums.com/fo...ing-sound-from-engine-bay.149616/post-3157506

Cute, but not everything adds up to the conclusion in that story:

1. Me and you tried dry lube with identical results. Removing it alone, and nothing else, had a high likelihood to yield positive results.
2. " they added ceramic grease to the splines " - i bet you that is what made difference, ill take it further to bet you that any grease applied (their ceramic unicorn or any off the shelf type) would have resolved fiasco with dry grease you have experience. Question is for how long? Grease alone is not the problem, it becomes a problem over time, once it looses its properties and gets mixed with clutch dust. We could have all simply cleaned dirty splines, reapplied wrong/right grease, and call it a success until problem returns again in X amount of miles.
3. Bleeding hydraulics was done right after reassembly. It is extremely highly probable that your issue was already resolved by either #1 or #2.

So to go as far as labeling hydraulics as THE ISSUE, and be 100% convinced there is nothing wrong with the ACT clutch...

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[BHank0688]

I wish someone would make an actual beefed up version of the stock hydraulic setup. Not convinced either way it’s the cause of issues, but I’ve been saying for a while now something is up with the stock setup. Possibly letting air in/ maybe just crap parts, which seems to be something Jeep would do.

 

[gek]

Cute, but not everything adds up to the conclusion in that story:

1. Me and you tried dry lube with identical results. Removing it alone, and nothing else, had a high likelihood to yield positive results.
2. " they added ceramic grease to the splines " - i bet you that is what made difference, ill take it further to bet you that any grease applied (their ceramic unicorn or any off the shelf type) would have resolved fiasco with dry grease you have experience. Question is for how long? Grease alone is not the problem, it becomes a problem over time, once it looses its properties and gets mixed with clutch dust. We could have all simply cleaned dirty splines, reapplied wrong/right grease, and call it a success until problem returns again in X amount of miles.
3. Bleeding hydraulics was done right after reassembly. It is extremely highly probable that your issue was already resolved by either #1 or #2.

So to go as far as labeling hydraulics as THE ISSUE, and be 100% convinced there is nothing wrong with the ACT clutch...

 

[JeepinPete]

I wish someone would make an actual beefed up version of the stock hydraulic setup. Not convinced either way it’s the cause of issues, but I’ve been saying for a while now something is up with the stock setup. Possibly letting air in/ maybe just crap parts, which seems to be something Jeep would do.

The stock parts are engineered with the stock setup in mind. They work fine for what they were designed to work with. ACT and Centerforce are replacing a twin disc clutch with a single disc clutch. This requires a higher clamp load to work, offset to a degree by the increased diameter of the clutch. The stock throwout bearing release arm will deflect more, that is simple physics. Whether is matters or not is another matter.

Dodge/Jeep has used this release arm design for decades, it is nothing new. What seems to be new for the JL is the very short actuation travel of the stock clutch design, and the hydraulic system designed for that fact. A longer throw clutch system isn't going to be as sensitive to anything being slightly out of spec compared to a short throw design. A small bubble might each up a couple thousands of an inch of travel which matters on the JL whereas it wouldn't on the JK.

 

[Duece McCracken]

The stock parts are engineered with the stock setup in mind. They work fine for what they were designed to work with. ACT and Centerforce are replacing a twin disc clutch with a single disc clutch. This requires a higher clamp load to work, offset to a degree by the increased diameter of the clutch. The stock throwout bearing release arm will deflect more, that is simple physics. Whether is matters or not is another matter.

Dodge/Jeep has used this release arm design for decades, it is nothing new. What seems to be new for the JL is the very short actuation travel of the stock clutch design, and the hydraulic system designed for that fact. A longer throw clutch system isn't going to be as sensitive to anything being slightly out of spec compared to a short throw design. A small bubble might each up a couple thousands of an inch of travel which matters on the JL whereas it wouldn't on the JK.

I'm running the Centerforce JK slave, and braided line. It has had zero effect on my clutch issues, lmao

I still have to drop my trans again and swap to the nickle plated ACT clutch disc, but in my case its a lubrication/tolerance issue for sure. Has nothing to do with the hydraulics for me. I did the troubleshooting, I replaced parts, bled etc. Zero effect.

I'm going to polish up the trans input shaft some while it's apart. Then sparsely lube with the ACT grease on re-assembly. Clean and relube the pivot fork assembly as well. Look for bends or stress points. Just try to get as much additional data as possible.

This is probably not happenening on my end until August or Sept though.

I've just been living with the gear lockouts and what not. It has not gotten worse. It just reached a point of suckery, and has stayed there for like 20k miles.

 

[OldGuyNewJeep]

it becomes a problem over time

 

[OldGuyNewJeep]

I wish someone would make an actual beefed up version of the stock hydraulic setup. Not convinced either way it’s the cause of issues, but I’ve been saying for a while now something is up with the stock setup. Possibly letting air in/ maybe just crap parts, which seems to be something Jeep would do.

Centerforce has done that and @_oIIIIIIIo_ has it installed. New master, new line, elimination of slave in favor of a hydraulic throw out. He says it’s great.

I am seriously considering ditching my ACT and copying his setup. I’m gun shy because he’s literally the only reviewer of this setup that I can find online, and that makes me nervous. It’s a $3k proposition, at least!

 

[OldGuyNewJeep]

Great point. I think I will add vacuum bleeding to my list of normal maintenance items.

Any source for the rubber plug that’s required to do this? I have Harbor Freight down the road where I can grab a vac, but don’t know where to get something to use as a plug. Leaving for a long road trip on Monday and would love to bleed overnight before I go.

 

[BHank0688]

Centerforce has done that and @_oIIIIIIIo_ has it installed. New master, new line, elimination of slave in favor of a hydraulic throw out. He says it’s great.

I am seriously considering ditching my ACT and copying his setup. I’m gun shy because he’s literally the only reviewer of this setup that I can find online, and that makes me nervous. It’s a $3k proposition, at least!

I meant still an externally mounted slave just an upgrade over stock. And as far as vacuum bleeding through the reservoir I didn’t have any lucky with it setting the vac to 15. Left it over night and never moved. Still had really low pedal clutch engagement. Best results always come from removing the slave, aiming the value up, and gravity bleeding for me. But if you want to try it I used a “black rubber stopper” from Home Depot. They have them in stock at my local store anyhow and only a few bucks. I just can’t remember what size I bought so take a measurement of the opening and check the stoppers when you are there. Easy to drill a hole in the middle of them and use one of the mighty vac adapters to plug into that hole.

 

[andrei]

Centerforce has done that and @_oIIIIIIIo_ has it installed. New master, new line, elimination of slave in favor of a hydraulic throw out. He says it’s great.

I am seriously considering ditching my ACT and copying his setup. I’m gun shy because he’s literally the only reviewer of this setup that I can find online, and that makes me nervous. It’s a $3k proposition, at least!

I was leaning toward trying it, but the idea of a hydraulic TOB inside the bellhousing of an adventure vehicle doesn’t sit well with me. On one hand, it’s no different from a slave or master cylinder, if those can last for years, why can’t a hydraulic bearing? On the other hand, all shifting ability would be gone the moment it springs a leak, tow truck, and back on the lift your Jeep goes.

Some solid, 5 year long data involving mudding, water crossings, dust, freezing temperatures, and most importantly vibrations and lots of vibrations, proving its durability and functionality would go a long way. That would be a good enough selling point for me.

My own anecdotal experience is an apples to oranges comparison, but I have tried plenty of products designed and rigorously tested in or around Comiefornia , “We have 20 years of experience! Just buy it! Your Jeep needs it!” , only to bring them to the East Coast and watch them slowly degrade with each offroading trip.

 

[andrei]

I meant still an externally mounted slave just an upgrade over stock. And as far as vacuum bleeding through the reservoir I didn’t have any lucky with it setting the vac to 15. Left it over night and never moved. Still had really low pedal clutch engagement. Best results always come from removing the slave, aiming the value up, and gravity bleeding for me. But if you want to try it I used a “black rubber stopper” from Home Depot. They have them in stock at my local store anyhow and only a few bucks. I just can’t remember what size I bought so take a measurement of the opening and check the stoppers when you are there. Easy to drill a hole in the middle of them and use one of the mighty vac adapters to plug into that hole.

I saw 'through reservoir' method in one of the videos linked here somewhere, but have you seen any instructions on how to actually do it properly?
That method does not make sense, it is a closed line, even if there was air in the line it would not move towards vacuum. In order for it to work, something on other end needs to be open, like slave valve or leak in the system. OR vacuum need to have enough pressure to make slave piston retract back and flow fluid back into reservoir.

So in my opinion proper way to do it is to do reverse process:

• connect a tube to slave bleeder
• submerge tube into a bottle with fluid
• connect vacuum to reservoir
• open slave bleeder and begin reversed fluid extracting process

Thinking out loud here

 

[OldGuyNewJeep]

I was leaning toward trying it, but the idea of a hydraulic TOB inside the bellhousing of an adventure vehicle doesn’t sit well with me. On one hand, it’s no different from a slave or master cylinder, if those can last for years, why can’t a hydraulic bearing? On the other hand, all shifting ability would be gone the moment it springs a leak, tow truck, and back on the lift your Jeep goes.

Some solid, 5 year long data involving mudding, water crossings, dust, freezing temperatures, and most importantly vibrations and lots of vibrations, proving its durability and functionality would go a long way. That would be a good enough selling point for me.

My own anecdotal experience is an apples to oranges comparison, but I have tried plenty of products designed and rigorously tested in or around Comiefornia , “We have 20 years of experience! Just buy it! Your Jeep needs it!” , only to bring them to the East Coast and watch them slowly degrade with each offroading trip.

Yeah, I hear you. They have been around since the 80s, but the amount of heat they must have to withstand being inside the bell housing makes me nervous. The seals will fail, eventually, and we just don’t know how long eventually is…

I still think I want to do it, though. I’m tired of being annoyed by a vehicle that I bought to bring me joy.

 

[BHank0688]

I saw 'through reservoir' method in one of the videos linked here somewhere, but have you seen any instructions on how to actually do it properly?
That method does not make sense, it is a closed line, even if there was air in the line it would not move towards vacuum. In order for it to work, something on other end needs to be open, like slave valve or leak in the system. OR vacuum need to have enough pressure to make slave piston retract back and flow fluid back into reservoir.

So in my opinion proper way to do it is to do reverse process:

• connect a tube to slave bleeder
• submerge tube into a bottle with fluid
• connect vacuum to reservoir
• open slave bleeder and begin reversed fluid extracting process

Thinking out loud here

I saw something about it somewhere at some point lol. Helpful, yes I know. From what I recall it was just set the vacuum from reservoir and let it sit overnight. Not opening the slave or doing anything else. What you said makes sense, but I tried it and didn’t have any success with it after brake/ clutch fluid change. So back to old gravity bleeding and it was back to normal.

 

[andrei]

Yeah, I hear you. They have been around since the 80s, but the amount of heat they must have to withstand being inside the bell housing makes me nervous. The seals will fail, eventually, and we just don’t know how long eventually is…

I still think I want to do it, though. I’m tired of being annoyed by a vehicle that I bought to bring me joy.

Since i have to pull transmission out again, and the idea of going back to clunky and jerky OEM clutch makes me cringe, i reached out to ACT about their funky looking street racing 6 spoke ceramic clutch disk.

My thinking is based on previous experience with ceramic brake pads - they last longer and significantly less dusty. However, i don't know how das wunder rennen thingy would perform in Jeeping applications. Will see what ACT has to say.

So, if i do end up being a test dummy for this approach, and you can wait another year and half (that is about 7500 miles for me), i will report back and might save you from $3000 of additional pain the ass.


EDIT: just read post about South Bend experience (https://www.jlwranglerforums.com/fo...periences-south-bend-dual-disc-review.142418/). Details about ACT in it are simply soul crushing.

 

[mudpup]

Centerforce has done that and @_oIIIIIIIo_ has it installed. New master, new line, elimination of slave in favor of a hydraulic throw out. He says it’s great.

I am seriously considering ditching my ACT and copying his setup. I’m gun shy because he’s literally the only reviewer of this setup that I can find online, and that makes me nervous. It’s a $3k proposition, at least!

Wow I’m checking in after a long absence.
I thought you were the biggest ACT cheerleader on the planet.
What happened?
16k miles on my CFII and it is still perfect.

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