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

[Reflektr]

The symptom is difficulty shifting into low gears

The cause is a clutch disc that is still spinning at or near engine rpm even though the pressure plate has been disengaged and is no longer applying pressure

Figuring out the cause of the cause has been the challenge. Common ideas are that it Could be sticking splines on the input shaft or it Could be a clutch hose ballooning and not fully disengaging the clutch.

I think It could simply be insufficient drag on the input shaft from exceptionally low drag bearings meaning there's not enough drag to break the imbedded friction the last time the clutch disc was clamped down on by the pressure plate .
It's been a fairly unprecedented cause of a cause

You’re onto something with it being a multitude of things for sure. Mine is a ‘25 Willys with 9,000 miles on the ticker and it started doing all of the things around 5,000 miles or so. Every once in awhile so-so dependent on weather conditions, all of the stars will align and I’ll get a smooth drive either to work or on the way home, but most of the time it’s like wiggling a canoe paddle through a pillowcase full of padlocks until it’s not.

Shifting at a different rpm will help this time, but not next. Letting out the clutch slow and not giving it gas will provide a smooth and quiet shift this gear, but not next. Rocking the stick adjacent will help with the notchy feeling this time, but not the next. Etc…

Curious to see how another one felt, I test drove a brand new 2026 Willys 6-speed with 25 miles on the odometer. Right off of the lot, it was already twice as bad, twice as notchy and just as inconsistent if not worse than mine. How can this even be?

Sponsored

 

[Toycrusher]

I think the clutch pressure plate and disk is a well traveled path for over 100 years. The pressure plate and disk used by ACT on the JL is not a unique design, nor are the materials. My thoughts from observing one ACT JL and trying to bleed it over the course of days, is that this is a simple issue of deflection of the components that move the throwout bearing. The cause of the deflection, I believe is the added forces of the ACT pressure plate, on the actuation components. A contributing factor may be the plastic body of the throwout bearing heating up and having higher friction on the transmission snout.

The "chink in the armor" of that theory is that the sticking was happening even with internal slave cylinders with gobs of throw yet still the disc would stick

 

[WJ43]

I think the clutch pressure plate and disk is a well traveled path for over 100 years. The pressure plate and disk used by ACT on the JL is not a unique design, nor are the materials. My thoughts from observing one ACT JL and trying to bleed it over the course of days, is that this is a simple issue of deflection of the components that move the throwout bearing. The cause of the deflection, I believe is the added forces of the ACT pressure plate, on the actuation components. A contributing factor may be the plastic body of the throwout bearing heating up and having higher friction on the transmission snout.

I would agree that it's definitely some sort of heat soak that compounds the issue. Even with my recent success in bleeding it better, it definitely gets more difficult to shift after sitting in traffic for 45 minutes to an hour.

 

[RubiSc0tt]

A bad manual is still more engaging than the best automatic.

i have been a die hard manual guy for years. A V8 solves this issue for me.

 

[WJ43]

i have been a die hard manual guy for years. A V8 solves this issue for me.

If only that v8 had a manual.... There is a template for this - Cadillac ct5-v blackwing

 

[SlickRicksWilly]

If only that v8 had a manual.... There is a template for this - Cadillac ct5-v blackwing

That sounds fun, let's put one in my 2 door.

 

[Toycrusher]

I would agree that it's definitely some sort of heat soak that compounds the issue. Even with my recent success in bleeding it better, it definitely gets more difficult to shift after sitting in traffic for 45 minutes to an hour.

Actually, I forgot how much worse it would get in stop & go traffic, that fits better into my theory than I thought. Heat soak thins out the oil in the transmission, which means there is even less drag than before and the input shaft can spin even more freely. Add to this the fact that this transmission does not use a pilot bearing or bushing, there is even LESS drag than normal to slow the clutch disc down.
There literally just might not be enough drag to make the disc WANT to break friction with the flywheel

 

[Toycrusher]

If only that v8 had a manual.... There is a template for this - Cadillac ct5-v blackwing

Doesn't need to be anything special, run-of-the-mill 5.7 for me!

 

[Reflektr]

Actually, I forgot how much worse it would get in stop & go traffic, that fits better into my theory than I thought. Heat soak thins out the oil in the transmission, which means there is even less drag than before and the input shaft can spin even more freely. Add to this the fact that this transmission does not use a pilot bearing or bushing, there is even LESS drag than normal to slow the clutch disc down.
There literally just might not be enough drag to make the disc WANT to break friction with the flywheel

Could this be why ditching the ATF +4 in favor of a manual transmission gear box oil helps with some cases?

 

[gek]

I’m subscribed to all the manual clutch threads and have read every post. They all have some issues. My plan is to replace with another OEM clutch, at least until someone figures out what the real problem is.

The real problem is the OEM clutch and them attempting to fix a hardware problem with software updates.

I started having issues at 15k on ACT and going back to OEM wasn't even an option I considered. While i was considering looking at autos I found one local that was basically my exact jeep, options wise, but an auto and I took that as a sign to ditch the clutch issues entirely.

I miss my manual, but never once have I missed it enough to consider going back to a manual with the factory jl clutch. Helps that this auto is truly one of the best automatic transmissions I've driven.

 

[WJ43]

Could this be why ditching the ATF +4 in favor of a manual transmission gear box oil helps with some cases?

Can you elaborate on changing from atf 4? Is that in the transmission itself? That is something I would be willing to try

 

[RubiSc0tt]

If only that v8 had a manual.... There is a template for this - Cadillac ct5-v blackwing

Sadly it's not going to happen from the factory. Every reasoning I've ever seen is "The manual take rate is too low", but dealers also use the quick order packages and stuff that come with auto transmissions and most people don't want to be bothered with or can't afford factory ordering, so they just buy what is out there already. This creates a self fulfilling prophecy. That's aside from any of the mechanical/ engineering/ regulatory stuff of making the drive line live and last behind a manual transmission + V8 for something like a Wrangler. They would have to upgrade a lot.

There are some great aftermarket options though, and the good news is it's easier to convert a 392 to a stick shift than it is to convert a stick shift to a 392.

Doesn't need to be anything special, run-of-the-mill 5.7 for me!

@yokramer You want to break the news to this man, since you enjoy this?

 

[yokramer]

@yokramer You want to break the news to this man, since you enjoy this?

They are already in the manual transmission thread clearly good choices arent their strong suit. It would be punching down too far.

 

[jeepingib]

A bad manual is still more engaging than the best automatic.

I still get a workout for my left calf muscle with the VW that has become the daily. I don't need to suffer from a poor design with the Jeep.

 

[yokramer]

I still get a workout for my left calf muscle with the VW that has become the daily. I don't need to suffer from a poor design with the Jeep.

Yea that is a hella dumb take. Like having a transmission that feels like total garbage that could possibly catch your car on fire is some how better because manual? Dude needs to take a step back and re-evaluate his life choices.

Sponsored