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

[Maverick909]

I figured I'd post this in case anyone was interested. This is video from today just shifting through all the gears. Engine was on my Jeep was stationary.

At the moment it's pretty inconsistent. Sometimes it will still go into 1st without feeling like it is hitting a wall.

when your having trouble with first not going in have you tried going into second then back into first? If so does it go into first easier? I have a ford ranger at the office that had this problem and it came out to the synchros failing.

another thing i read a while back is that the ECU controls the lock out on rev and 1st gear to protect the transmission. I have issues down shifting into first until below 4mph. other than that zero issues shifting in and out when in park. not sure if its a ecu glitch youre having but just a thought for you. bummed you're having this big of a pain.

Sponsored

 

[roaniecowpony]

Getting my Jeep back today and the service writer said my shifting issue with first gear is due to the batteries being drained, so they replaced both batteries. I asked him how does the batteries affect the shifting ? He started not to make any sense so I just left it at that. Picking it up later on today.

 

[SadRobot]

when your having trouble with first not going in have you tried going into second then back into first? If so does it go into first easier? I have a ford ranger at the office that had this problem and it came out to the synchros failing.

another thing i read a while back is that the ECU controls the lock out on rev and 1st gear to protect the transmission. I have issues down shifting into first until below 4mph. other than that zero issues shifting in and out when in park. not sure if its a ecu glitch youre having but just a thought for you. bummed you're having this big of a pain.

It's still unclear to me if the JL has a 1st gear synchro. I can't find any info online and it seems it's not possible to buy a 1st/reverse synchronizer for a JL.

The best info I can find is that reverse does not have a synchronizer. So if it's locking up or having issues in reverse it's not because of a synchro. And reverse/1st are the same gear.

I'll be happy to admit I'm wrong though if anyone can show a video or image showing that a 1st gear synchro exists in the JL.

 

[Duece McCracken]

It's still unclear to me if the JL has a 1st gear synchro. I can't find any info online and it seems it's not possible to buy a 1st/reverse synchronizer for a JL.

The best info I can find is that reverse does not have a synchronizer. So if it's locking up or having issues in reverse it's not because of a synchro. And reverse/1st are the same gear.

I'll be happy to admit I'm wrong though if anyone can show a video or image showing that a 1st gear synchro exists in the JL.

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

 

[azwjowner]

It's still unclear to me if the JL has a 1st gear synchro.

It does. It's obvious if you shift into 1st while moving, which I have done (at slow speeds). There's no grinding, the revs match.

 

[roaniecowpony]

It's still unclear to me if the JL has a 1st gear synchro. I can't find any info online and it seems it's not possible to buy a 1st/reverse synchronizer for a JL.

The best info I can find is that reverse does not have a synchronizer. So if it's locking up or having issues in reverse it's not because of a synchro. And reverse/1st are the same gear.

I'll be happy to admit I'm wrong though if anyone can show a video or image showing that a 1st gear synchro exists in the JL.

Most modern transmissions have a first gear synchro. If you're driving and try to downshift to first and hear the gears spin up as you push it into gear, it has a synchro.

 

[SadRobot]

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

Can you post some of that documentation? I'd be interested in reading it.

 

[Duece McCracken]

Can you post some of that documentation? I'd be interested in reading it.

It wasn't great. I had to hunt down drawings from Aisin itself. Which I will have to hunt down again.

 

[roaniecowpony]

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.

 

[SadRobot]

It wasn't great. I had to hunt down drawings from Aisin itself. Which I will have to hunt down again.

Yeah you'd think there would at least be 1 good diagram or video or something out there.

 

[OldGuyNewJeep]

the ECU controls the lock out on rev and 1st gear to protect the transmission

Do you have a source for that? I don't see how it's possible.

There is a gear position sensor and when my Jeep was new (2018) and hadn't had any recalls I'd sporadically get an annoying alert that said something like "speed to high for 1st." It would happen when just shifting to neutral while in motion, but sporadically. They fixed with one of the recalls, but I think if tried pushing into first while going fast enough it'd still trigger. I'm not gonna test that, even with my pedal planted firmly to the floor. 1st is for starting from a complete stop, no ifs and or buts for me. (With my ACT and Rubicon gearing I can start in 2nd without having to slip the clutch very much, in fact.)

If it somehow were possible that the ECU could lockout 1st, then the "it's the batteries" wouldn't be impossibly far-fetched, though far-fetched nonetheless.

 

[SadRobot]

If it somehow were possible that the ECU could lockout 1st, then the "it's the batteries" wouldn't be impossibly far-fetched, though far-fetched nonetheless.

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

 

[ski-line900]

Seems there is some type of lockout mechanism, dunno about electrical vs mechanical.

 

[Maverick909]

Do you have a source for that? I don't see how it's possible.

There is a gear position sensor and when my Jeep was new (2018) and hadn't had any recalls I'd sporadically get an annoying alert that said something like "speed to high for 1st." It would happen when just shifting to neutral while in motion, but sporadically. They fixed with one of the recalls, but I think if tried pushing into first while going fast enough it'd still trigger. I'm not gonna test that, even with my pedal planted firmly to the floor. 1st is for starting from a complete stop, no ifs and or buts for me. (With my ACT and Rubicon gearing I can start in 2nd without having to slip the clutch very much, in fact.)

If it somehow were possible that the ECU could lockout 1st, then the "it's the batteries" wouldn't be impossibly far-fetched, though far-fetched nonetheless.

Doesn’t show for being off or stopped but here’s the manual on lock out

 

[Maverick909]

Can you post some of that documentation? I'd be interested in reading it.

Yes, the Aisin D478 manual transmission does have synchros. chat gpt says it does too LOL

Sponsored