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

[OldGuyNewJeep]

Wouldn't this mean if your battery goes dead your shifter would stop working if it was controlled electronically?

I was thinking more along the lines of failing battery equals squirrelly everything. That's from my own experience back when I had a stock setup with that crappy AUX enabled. I was getting very strange glitches until I figured out I needed a new battery; a.k.a. gremlins.

I ended up disconnecting the AUX (Fuse F42 and disconnect negative) and putting in a 94R Odyssey (fits like a glove in Rubicon with tow package). All the gremlins went away and never came back.

Contrast that experience to my wife's Yukon that literally sends us an e-mail went the battery is low. At least in did when the 5 years of free OnStar was active. Even with no fancy e-mail, when the battery dies it does what one would expect - fails to start!

Yeah, it might be obvious that I am not a fan of Jeep's electronics!

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[Maverick909]

Although the manual states that it's "synchronized in all gear ranges", I had not seen transmissions with a reverse synchronized in the past. But, it's been a long time since I dug into a manual transmission. So, there's that.

where did you find this? ive been searching for the AL6 or D478 transmission booklet with zero luck

 

[fczabala]

where did you find this? ive been searching for the AL6 or D478 transmission booklet with zero luck

alldata

 

[58Willys]

From the factory service manual:

• 1st gear is syncronized.
• Reverse is not syncronized.
• I don't see anything electronic as to a first gear lockout. Bad batteries are not causing shifting issues.
• There are a couple parts shown which I don't know what they do. They could be mechanical 1st gear lockouts, don't know. Syncros can prevent downshifting to a lower at too high a speed though.

If you can't shift into 1st with minimal effort when stopped, probably a dragging clutch. This can be tested by raising rear wheels, transfer case in 2WD, put tranny in 1st or reverse with clutch disengaged (pedal to the floor); and see if there is any rear driveshaft movement at all. If driveshaft turns, clutch is dragging.

Could be the stock hydraulics are just not sufficient to fully disengage these aftermarket clutches (could be the case with OEM as well, which could have caused the issues to begin with). A lot of folks are saying it shifts OK when cold, but fails when warm. Syncros are nothing but wet clutches and work better when tranny fluid is cold, thick, and sticky; and loose ability to work as well when tranny fluid is warm, thin, and slippery. Could be the syncros can slow the main shaft when cold, but cannot put sufficient pressure on the main shaft when warm.

A slave cylinder can fail internally, fluid leaks past the piston inside; no external leaks; it just won't disengage the clutch.

Fortunately, my original clutch is still working. Finger crossed until this gets resolved.

 

[roaniecowpony]

where did you find this? ive been searching for the AL6 or D478 transmission booklet with zero luck

Thats out of my Tech Authority service manual.

 

[Duece McCracken]

Thats out of my Tech Authority service manual.

I trust that more than what Jeep says. They dont have a clue what the inside of their 3rd party transmission is like.

 

[Jeremynolan94]

Those of you with the ACT clutch, how much do you find it vibrates when engaged? I feel like mine is getting worse. There is a very noticable vibration or harshness in the pedal, almost to the point where I can feel it vibrate the floorboard when accelerating. This is in addition to the creaking/croaking sound that has been detailed here and in other threads. I've had intermittent issues getting into 5th gear but otherwise shifting isn't too bad, just slow. Still, this car definitely doesn't shift nearly as well as when I first got it.

Wish I'd stuck with the stock clutch and just regeared. I'm wondering at what point I'd like to take it in to get looked at, since something doesn't quite feel right. That, or just trying to get the recall done.

 

[ski-line900]

Those of you with the ACT clutch, how much do you find it vibrates when engaged? I feel like mine is getting worse. There is a very noticable vibration or harshness in the pedal, almost to the point where I can feel it vibrate the floorboard when accelerating. This is in addition to the creaking/croaking sound that has been detailed here and in other threads. I've had intermittent issues getting into 5th gear but otherwise shifting isn't too bad, just slow. Still, this car definitely doesn't shift nearly as well as when I first got it.

Wish I'd stuck with the stock clutch and just regeared. I'm wondering at what point I'd like to take it in to get looked at, since something doesn't quite feel right. That, or just trying to get the recall done.

Mine didn't vibrate when engaged, but could feel it in the pedal when depressed (clutch disengaged). Got more pronounced with higher revs.

If you can feel vibration when accelerating and not pushing the clutch that doesn't sound like clutch, unless the throw out bearing is really wobbling around.

 

[autotragic]

The documentation I've read on the trans has synchronised R and every gear. I was hunting it down just to see exploded diagrams of the stacks.

Theres no ECU lockout that i've ever heard of. Theres just a gear position sensor. Its a manual trans. Heck, reverse is only locked out by a manual gate on the shifter itself. Without that physical obstruction, you'd be able to blow up your drivetrain whenever you wanted by mistaking R for 1st, lmao

There is a safety lock on 1st gear...if you are going too fast it won't let you engage first gear and you get a error message in the cluster.

I am actually wondering if there is some error that could cause that lockout to happen when it doesn't need to. Or even how the lockout works at all.

 

[notthenewguy]

Those of you with the ACT clutch, how much do you find it vibrates when engaged? I feel like mine is getting worse. There is a very noticable vibration or harshness in the pedal, almost to the point where I can feel it vibrate the floorboard when accelerating. This is in addition to the creaking/croaking sound that has been detailed here and in other threads. I've had intermittent issues getting into 5th gear but otherwise shifting isn't too bad, just slow. Still, this car definitely doesn't shift nearly as well as when I first got it.

Wish I'd stuck with the stock clutch and just regeared. I'm wondering at what point I'd like to take it in to get looked at, since something doesn't quite feel right. That, or just trying to get the recall done.

Just like @ski-line900 said. Mine vibrates with the clutch is depressed and gets worse at higher revs. As far as the recall is concerned, I have gone back and forth on getting it done or not. Some of the stories I’ve heard of the car just being rendered undrivable due to limp mode and having two dealers already basically tell me if that happens to my jeep after the recall it’s all on me, makes me back out from doing it. I’m planning on taking my jeep into a shop in February during some time off I have from work and just troubleshooting it. New cables, new hydraulics. If that doesn’t work then I’ll throw my stock clutch back in. If that does work, I’ll probably opt for the SBC clutch that @ski-line900 has since that clutch is essentially a stock design with more robust parts. How’s that clutch working out for you so far, @ski-line900?

 

[Duece McCracken]

There is a safety lock on 1st gear...if you are going too fast it won't let you engage first gear and you get a error message in the cluster.

I am actually wondering if there is some error that could cause that lockout to happen when it doesn't need to. Or even how the lockout works at all.

I've never experienced that. I downshift revmatch when decelling.

How do you even do this?

I guess I'll research dash error messages for this, then try to figure out what causes it.

In all my years of automotive wrenching, trans splitting etc, never seen this from a manufacturer. I either have never driven a manual trans that poorly, or its something Aisin does that no other manufacturer I have experienced has.

This is my 25th car/truck at this point, so Im not new to any of this. I'll need to do more research into this, but it doesnt make any sense from a mechanical standpoint. Never heard of a car being able to prevent a "money shift", well, never expected a jeep to be able to.

 

[autotragic]

I've never experienced that. I downshift revmatch when decelling.

How do you even do this?

I guess I'll research dash error messages for this, then try to figure out what causes it.

In all my years of automotive wrenching, trans splitting etc, never seen this from a manufacturer. I either have never driven a manual trans that poorly, or its something Aisin does that no other manufacturer I have experienced has.

This is my 25th car/truck at this point, so Im not new to any of this. I'll need to do more research into this, but it doesnt make any sense from a mechanical standpoint. Never heard of a car being able to prevent a "money shift", well, never expected a jeep to be able to.

I don't know how it works but get it into third gear (or higher) at a moderate speed and then gently attempt first, it blocks you.

 

[Steve104]

My half-baked theory: Looking at Duece McCracken’s post #362, I was struck by the fact that the transmission input shaft is not sitting in a pilot bearing like the transmissions used in the JKs. Could the increased mass of the aftermarket clutch/flywheel setups exceed the capacity of the Aisin input shaft to resist side loads? And could this then lead to the clutch not always completely disengaging?

 

[Duece McCracken]

My half-baked theory: Looking at Duece McCracken’s post #362, I was struck by the fact that the transmission input shaft is not sitting in a pilot bearing like the transmissions used in the JKs. Could the increased mass of the aftermarket clutch/flywheel setups exceed the capacity of the Aisin input shaft to resist side loads? And could this then lead to the clutch not always completely disengaging?

To be honest, its been awhile since I had a platform with a supported input shaft snout.

The bulk of the weight is the flywheel, which is crank mounted. The friction disc runs on the input shaft. The trans is dowel pinned indexed to the engine for alignment.

I could see the input shaft having the potential to sag, but all the weight is on the crank, which if it sagged it'd burn up the main bearings or wreck the rear main. Something to that effect.

Odds are, that its just a gummed up input shaft causing the friction disc not to fully release. Its the most likely culprit, also a PITA to fix. Im still dancing around dropping my trans again. Trying to exhaust every other avenue first, lol

 

[ski-line900]

Just like @ski-line900 said. Mine vibrates with the clutch is depressed and gets worse at higher revs. As far as the recall is concerned, I have gone back and forth on getting it done or not. Some of the stories I’ve heard of the car just being rendered undrivable due to limp mode and having two dealers already basically tell me if that happens to my jeep after the recall it’s all on me, makes me back out from doing it. I’m planning on taking my jeep into a shop in February during some time off I have from work and just troubleshooting it. New cables, new hydraulics. If that doesn’t work then I’ll throw my stock clutch back in. If that does work, I’ll probably opt for the SBC clutch that @ski-line900 has since that clutch is essentially a stock design with more robust parts. How’s that clutch working out for you so far, @ski-line900?

I'm still in the break-in period so reserving final judgement till I get some more miles.

It has developed a groan when taking off under load in first, my driveway exits to a hill, and seems more pronounced when cold. I've read this is common for dual disc, since the middle plate floats and vibrates some. Didn't do it for the first 200 miles, so hopefully it quiets down as it beds in.

Have had a couple times it didn't want to go easily into first. Releasing the clutch and trying again gets past it. I never force it in. If I roll up to a stop and don't release the clutch in neutral, it goes in super easy everytime.

All the other gears are very smooth.

The release point is 3/4 from the top, so definitely getting good disengagement.

Again, I'm waiting to update the other thread once I get more miles, but those are my first experiences.

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