Sponsored

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

notthenewguy

Well-Known Member
Joined
Oct 1, 2021
Threads
0
Messages
116
Reaction score
99
Location
California
Vehicle(s)
2016 Jeep JKU Sahara
I would think that partial clutch engagement would lead to grinding which no one has reported.
kine doesn’t quite front the way it would if you let out the clutch early but it is really rough going into gear. There’s a tactile and audible clunk and crunch going into gear. It isn’t consistent but as of the last week it’s been every single shift.
 

WJ43

Well-Known Member
First Name
Wayne
Joined
Aug 3, 2022
Threads
5
Messages
109
Reaction score
65
Location
CA
Vehicle(s)
06 commander, 16 Ram 2500, 23 ram 3500, 22 Rubicon
my jeep shifts perfectly fine with the car off. All the gears go in perfectly smooth. When it’s on it’s really rough. Bleeding improves it but then it returns. Maybe I need to swap out my master cylinder. I already had a new slave put in. Would a stock slave cylinder with a CF master cylinder work? I think someone in this thread is running that setup. Might give it a shot next.

was also wondering, are all the people who are experiencing issues with the ACT clutch running the pro mass flywheel? Are the people running the street mass flywheel fine? Just a thought.
I have the CF master with a stock slave. It is a bit heavy and we only have about 500 miles since the master was put in, but so far it is smooth and has predictable clutch engagement.
 

notthenewguy

Well-Known Member
Joined
Oct 1, 2021
Threads
0
Messages
116
Reaction score
99
Location
California
Vehicle(s)
2016 Jeep JKU Sahara
I have the CF master with a stock slave. It is a bit heavy and we only have about 500 miles since the master was put in, but so far it is smooth and has predictable clutch engagement.
thanks for the reply. I will consider this if I decide to swap out the hydraulics. Haven’t had time to bleed the slave again like I thought I would but that’s my next step and if that doesn’t work then CF master cylinder it is.
 

WJ43

Well-Known Member
First Name
Wayne
Joined
Aug 3, 2022
Threads
5
Messages
109
Reaction score
65
Location
CA
Vehicle(s)
06 commander, 16 Ram 2500, 23 ram 3500, 22 Rubicon
thanks for the reply. I will consider this if I decide to swap out the hydraulics. Haven’t had time to bleed the slave again like I thought I would but that’s my next step and if that doesn’t work then CF master cylinder it is.
The shop changed the hydraulic lines to use the braided one that CF provides with the kit (I bought the master and slave together) but didn't use the slave in the end because the OEM one tested out okay. I'm still wondering if the stock hydraulic line is part of the problem because it is so narrow and has so many bends
 

Sponsored

jlewissystem

Well-Known Member
First Name
J
Joined
Jan 24, 2019
Threads
55
Messages
1,168
Reaction score
2,357
Location
STL
Vehicle(s)
2019 JLUR MANUAL Mojito!
Build Thread
Link
Vehicle Showcase
1
I have the CF2 with included master/slave and line. I just started having these symptoms. Just did a slave bleed and top/vacuum bleed. Not much driving on it yet, but seems improved. My clutch has 20k on it. Following..
 

notthenewguy

Well-Known Member
Joined
Oct 1, 2021
Threads
0
Messages
116
Reaction score
99
Location
California
Vehicle(s)
2016 Jeep JKU Sahara
The shop changed the hydraulic lines to use the braided one that CF provides with the kit (I bought the master and slave together) but didn't use the slave in the end because the OEM one tested out okay. I'm still wondering if the stock hydraulic line is part of the problem because it is so narrow and has so many bends
that’s another thing I was wondering. Does the stock like cause any sort of delay in response due to hoe narrow it is?
 
OP
OP

SadRobot

Well-Known Member
Joined
Aug 31, 2019
Threads
144
Messages
7,494
Reaction score
20,078
Location
Los Angeles
Vehicle(s)
2025 Prius LE
I have the ACT kit with about 13k miles on it. 68k miles on ODO. My fix is to put it in 4th then 1st. Ok so far. When the car is off, it goes through the gears smoothly.

edit: I’m now having issues putting in reverse. I have to put into another gear then in reverse. It also makes a weird sound sometimes when taking off on 1st.
Is it a groan that sounds like Chewbacca? Mine started that a couple weeks ago.
 

fspalt

Well-Known Member
First Name
Frank
Joined
Oct 26, 2021
Threads
23
Messages
229
Reaction score
165
Location
Baltimore, MD
Vehicle(s)
2021 JLUR
So mine is now to the point now that it will pretty much never go into first or reverse from a stop at idle. The only way to get it in gear at a stop is to rev the engine to about 2500-3000rpm then it slides right in. So my driving style has been downshift into first coming to a stop and hold the clutch in through red lights. My ACT has made the Chewbacca sound for as long as I can remember now. Although I’m pretty sure I didn’t have it for the first few thousand miles.
 
OP
OP

SadRobot

Well-Known Member
Joined
Aug 31, 2019
Threads
144
Messages
7,494
Reaction score
20,078
Location
Los Angeles
Vehicle(s)
2025 Prius LE
So mine is now to the point now that it will pretty much never go into first or reverse from a stop at idle. The only way to get it in gear at a stop is to rev the engine to about 2500-3000rpm then it slides right in. So my driving style has been downshift into first coming to a stop and hold the clutch in through red lights. My ACT has made the Chewbacca sound for as long as I can remember now. Although I’m pretty sure I didn’t have it for the first few thousand miles.
Yeah I've been finding work arounds now as well. At the moment I'm just grateful to have a car back so have been dealing with the annoyance of it all.
 

Sponsored

ajLEEP21

Active Member
First Name
Allan
Joined
Dec 13, 2021
Threads
8
Messages
40
Reaction score
25
Location
SoCal
Vehicle(s)
2021 JL Rubicon
Clubs
 
Is it a groan that sounds like Chewbacca? Mine started that a couple weeks ago.
Yeah but it’s a hit or miss. It seems like it only does it when it’s hot outside or when the tranny is warmer from a lot of driving. Today I had 0 issues. Looks like Mr. Hyde didn’t come out.
 
OP
OP

SadRobot

Well-Known Member
Joined
Aug 31, 2019
Threads
144
Messages
7,494
Reaction score
20,078
Location
Los Angeles
Vehicle(s)
2025 Prius LE
Yeah but it’s a hit or miss. It seems like it only does it when it’s hot outside or when the tranny is warmer from a lot of driving. Today I had 0 issues. Looks like Mr. Hyde didn’t come out.
I'm almost convinced mine is heat related as well. Like today I drove about 5 minutes total and right out the garage the cold Jeep drove totally normal. Shifting right into 1st gear each time the whole drive. But I know if I hit the freeway for about 20 minutes by the time I exit it'll be hard to shift into 1st again.

Why heat is affecting things I don't know. And what the catalyst to set this whole thing off was I also don't know. Something happened at 10k miles to make this change. I'm hoping once the clutch comes out it'll be pretty obvious why.
 

Duece McCracken

Well-Known Member
Joined
Mar 25, 2023
Threads
1
Messages
241
Reaction score
467
Location
Croydon, PA
Vehicle(s)
2023 JTR 6spd, 2019 Mustang Bullitt
Build Thread
Link
I'm almost convinced mine is heat related as well. Like today I drove about 5 minutes total and right out the garage the cold Jeep drove totally normal. Shifting right into 1st gear each time the whole drive. But I know if I hit the freeway for about 20 minutes by the time I exit it'll be hard to shift into 1st again.

Why heat is affecting things I don't know. And what the catalyst to set this whole thing off was I also don't know. Something happened at 10k miles to make this change. I'm hoping once the clutch comes out it'll be pretty obvious why.

Im still leaning towards contaminated grease on the input shaft splines. Thermal expansion taking some of the tolerance out of the mating parts, then the disc getting hung up on the splines.

The mileage produces dust off the friction material. Which can collect on the greased splines.

This is the theory I'm accepting at this moment.

Its not hydraulics, its not a lockout solenoid, its not alignment, its not shifter cables, its not synchros.

These are my thoughts with my personal troubleshooting and personal installation of all components.
 
OP
OP

SadRobot

Well-Known Member
Joined
Aug 31, 2019
Threads
144
Messages
7,494
Reaction score
20,078
Location
Los Angeles
Vehicle(s)
2025 Prius LE
Im still leaning towards contaminated grease on the input shaft splines. Thermal expansion taking some of the tolerance out of the mating parts, then the disc getting hung up on the splines.

The mileage produces dust off the friction material. Which can collect on the greased splines.

This is the theory I'm accepting at this moment.

Its not hydraulics, its not a lockout solenoid, its not alignment, its not shifter cables, its not synchros.

These are my thoughts with my personal troubleshooting and personal installation of all components.
That sounds like the best theory as well. I'm hoping to have some good news to report later this week on some findings. 🤞
Sponsored

 
 







Top