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

[gek]

I'm an outside observer to this issue, but I did help replace cylinders and bleed them 6 ways to Sunday and my background is engineering. I've also installed an ACT clutch on the OP's latest engine when we installed it, as well as having driven her Jeep with and without the issue. So, I guess I've been around the issue quite a bit and I'm familiar with the hardware.

I think we all can agree the pedal pressure of the ACT clutch is heavier than the OEM. I think this is the root of the issues that eventually develop. The initial installation with the proper lube on the throwout bearing works fine until the grease is depleted/dispersed/contaminated with dust. Then, I believe, the friction, on the sliding portion of the throwout bearing, goes up and the problem begins. The creaking noise is friction, which I believe is the plastic of the throwout bearing sliding and sticking on the shift fork and the snout of the transmission. The master and slave cylinders have plastic pushrods, IIRC. I think these pushrods deflect under the added pressure that occurs when the grease on the throwout bearing gives up.

Some potential solutions might be:
- a throwout bearing with lower friction material where it contacts the shift fork and snout of the transmission.
- replacing the master and slave pushrods with metal pushrods.

Are you saying the added resistance depletes/disperses the lube quicker or am I reading that wrong? Or are you just saying it is potentially causing pushrod deflection. The deflection of the pushrods makes sense in that scenario. Sticking throwout and deflecting pushrods could definitely make for engagement issues and possibly increase slippage creating more dust.

Minus the potential pushrod deflection with less pressure needing applied, I do wonder what lube they use on it from the factory. I know several manuals that went 50-100k on the original clutch without any engagement/shifting issues. If lube contamination/depletion is our main issue then I would think it would happen to stock vehicles more unless the lube was performing so much better.

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[roaniecowpony]

Are you saying the added resistance depletes/disperses the lube quicker or am I reading that wrong? Or are you just saying it is potentially causing pushrod deflection. The deflection of the pushrods makes sense in that scenario. Sticking throwout and deflecting pushrods could definitely make for engagement issues and possibly increase slippage creating more dust.

Minus the potential pushrod deflection with less pressure needing applied, I do wonder what lube they use on it from the factory. I know several manuals that went 50-100k on the original clutch without any engagement/shifting issues. If lube contamination/depletion is our main issue then I would think it would happen to stock vehicles more unless the lube was performing so much better.

My guess is the OEM clutch and throwout bearing, with its lower pressure, is not nearly as critical on the lube.

The issue also seems to be aggrevated when the clutch heats up. That's another reason I think the plastic throwout bearing is adding friction as it heats up.

 

[Steve104]

My guess is the OEM clutch and throwout bearing, with its lower pressure, is not nearly as critical on the lube.

The issue also seems to be aggrevated when the clutch heats up. That's another reason I think the plastic throwout bearing is adding friction as it heats up.

I thought the issue with the grease was that it was the wrong type (red and tacky), and so did not allow the clutch plate hub to slide freely along the splines of there transmission input shaft, resulting in the clutch plate getting hung up on either the pressure plate or flywheel. But you’re saying that its the thrust bearing that’s the issue?

 

[gek]

I thought the issue with the grease was that it was the wrong type (red and tacky), and so did not allow the clutch plate hub to slide freely along the splines of there transmission input shaft, resulting in the clutch plate getting hung up on either the pressure plate or flywheel. But you’re saying that its the thrust bearing that’s the issue?

Some shops used red and tacky and not the ceramlub that came with the kit. The red and tacky seems to accumulate dust much quicker.

 

[azjl#3]

Not understanding why ACT has not resolved this issue, it's their problem to fix, not you guys.

Thicker/more/ wrong lube, is a sign of a band aid system.

What does ACT say? They should say based on you guys input, don't install ACT on a 3.6

It's good after lots of work you have it back, but does it last 100,000 miles? Like most other manufacturer clutches...

Full disclosure, I have an ACT in my 347 NV4500 EB, has been in there 10 years, works great.

 

[OldGuyNewJeep]

Please do report back I'm definitely interested to hear the results on your end.

This plug is a perfect fit. Pumped to 15 and within 15 minutes it slowly crept to 14 where it seems to have stabilized. I’ll probably just leave it alone until tomorrow and update then.

 

[gek]

Not understanding why ACT has not resolved this issue, it's their problem to fix, not you guys.

Thicker/more/ wrong lube, is a sign of a band aid system.

What does ACT say? They should say based on you guys input, don't install ACT on a 3.6

It's good after lots of work you have it back, but does it last 100,000 miles? Like most other manufacturer clutches...

Full disclosure, I have an ACT in my 347 NV4500 EB, has been in there 10 years, works great.

To my understanding there are cases of this happening to every brand of aftermarket clutch and apparently on some mopar recall clutches, but ACT would appear to be the the most used supplier on the forum. We don't have enough info/adoption of CF's hydraulic bearing to have any solid data yet on it's reliability.

It is much larger than just an ACT issue, ACT does appear to be the one putting more effort into a resolution, at least outwardly.

 

[roaniecowpony]

Not understanding why ACT has not resolved this issue, it's their problem to fix, not you guys.

Thicker/more lube, is a sign of a poor design.

What does ACT say? They should say based on you guys input, don't install ACT on a 3.6

I believe ACT is working on this issue.

 

[SadRobot]

Not understanding why ACT has not resolved this issue, it's their problem to fix, not you guys.

Thicker/more/ wrong lube, is a sign of a band aid system.

What does ACT say? They should say based on you guys input, don't install ACT on a 3.6

It's good after lots of work you have it back, but does it last 100,000 miles? Like most other manufacturer clutches...

Full disclosure, I have an ACT in my 347 NV4500 EB, has been in there 10 years, works great.

Having worked with ACT now for a while they are aware some are having issues. On the other hand many are not. They've sold a lot of units and the amount not having issues outweighs those that are. @gek has never had a problem with his. Dirk and his crew have gone above and beyond to help me with the issues I've been having.

Something is just different with the JL manual transmissions than the previous versions. The JK does not lock out. It just seems like everything has to be perfect in the JL for it to shift right.

At the moment mine seems to be back to normal. I put some offroad miles on it yesterday and no issues shifting into 1st from a stop. Outside temps were in the low 90s. When it shifts right the ACT is great. So much better than the stock clutch.

I'm hoping it stays like this. It's going to see a lot less miles moving forward. The stress of it all along with my previous engine problems led me to give up on my Jeep as a daily driver. Out of the past 12 months my Jeep has spent 5 of those out of commission.

I drive a Prius now. It's the first auto I've ever owned. So far no regrets. Now any Jeep problems I have can get pushed aside till I can deal with them.

 

[andrei]

Any chance you looked at the new throwout bearing before it was put in? Was just wondering if it had any part numbers on it. Wish I didn’t just now think it that lol. It’s good to see your jeeps back up and going.

tob does not have any markings on it

 

[azjl#3]

I hope you all see this fixed fast. Problems with a device built in the 20's. 1920's.

 

[roaniecowpony]

My personal opinion is that the ACT clutch is no different than many other designs. Nothing really strange or new about the basic design. I think the extra force required to actuate the clutch is revealing weaknesses of OEM actuation system. I recall 50 years ago working on a friend's BB Chevy M22 trans/clutch and the pushrod was buckling from the extra force needed to move a McLeod clutch.

 

[m3reno]

I had the recall done last year because I was having issues going into 1st gear (stock unit) 22,000 miles. So after the dealership installed a new stock clutch, sure enough 10,000 miles later and I'm having the same issues. I haven't brought the vehicle back as I just slightly pull back as I'm going to 2nd and it falls right into 1st gear.

 

[OldGuyNewJeep]

https://www.jlwranglerforums.com/fo...ock-actuator-pawls-in-shifter-console.153546/

Another thread to follow.

 

[andrei]

My personal opinion is that the ACT clutch is no different than many other designs. Nothing really strange or new about the basic design. I think the extra force required to actuate the clutch is revealing weaknesses of OEM actuation system.

I 100% agree with everything you said and share the same opinion on this situation. Due to the complexity of the issue where more than one factor is likely at play, resolving it properly would require a test rig and active effort to identify root causes. ACT seems like doing fuckall about this, and their customers are clearly being used as the test rig. Reading all this “ACT magic grease” nonsense makes me think ACT is paying people to derail the thread until the problem either resolves itself or quietly disappears.

FYI, the pushrod on the Centerforce slave is metal, and there’s a report of the slave body breaking where the pushrod exits. That could suggest the combination of added resistance from the pressure plate + contaminated grease + heat expanding metal and plastic creates the perfect failure package.

I did asked ACT directly whether there a chance their pressure plate is too much force for stock slave, and if not the main issue, then at least a significant contributing factor to shifting issues. Their answer was "no". Additionally, hopefully i am not imagining this, either ACT or someone else said that amount of force directed at the center of pressure plate to release is not much.

There is also a good chance ACT pressure plates are inconsistent from one unit to another. I recently test drove another Jeep with an ACT kit installed, and the clutch feel was night and day compared to mine. It was slightly heavier than OEM, but very tactile and effortless. Mine, on the other hand, has always felt heavy and required extra muscle on the pedal.

Difference in TOB designs had be thinking if smooth surface of ACT design could be creating a "vacuum" like effect when it is packed with grease and slides on the guide. On other hand, i don't think the tolerances are that tight there to cause it.

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