I have owned a few manual transmission vehicles. My JK is the only one that has continually did the "grinding" thing between any two gears when cold.

 

i had alot of issues with my first JK..

grinding, kicking out of gear. Jeep says it was normal and from the bigger tires


alteast your getting a new one.

 

I occassionally grind going from 1st to 2nd gear. At first I thought that I was just releasing the clutch too quick or I wasn't fully in 2nd gear. However, it has continued. It seems to be worst in the cold weather and when my JK isn't warmed up. I don't want to damage anything, so I might go ahead and call the dealership. Boy I hope it's covered under warranty, but I am at 13k and don't have the lifetime powertrain warranty... boy this might hurt!

 

Good luck everyone on this one. I've had the same problem when cold, had it to two different dealership shops. I am told by Chrysler that this is normal, they will not do anything about it. I put Royal Purple Synchromax in the trans and it has helped some. Next time I am going to try Red Line synthetic, I have heard good things about this helping transmissions shift.

 

...I don't know...my trany has more what I'd call a 'tight' fit going from 1st to 2nd...some might call it a 'grind' I don't call it that, it's more like solid contact you can feel not really what I call a grind...I've chalked it up to normal operating characteristic of this transmission as I've had others standards in many other vehicles do the same thing. Still runs just fine, I have no issues with it at all. I'm just curious if others are referring to this as a flaw, a grinding problem??
I mean, yes you feel the gears from 1st and 2nd mesh together, but they slip right in on mine, it's not like it grinds and grinds and you can't get it in gear.
I'm gonna have to assume the OP was experiencing a far worse condition than what I consider normal for the dealership to replace the transmission.
And like someone else mentioned here, he said it was 'slipping' ?? I've never known a manual to 'slip' unless the clutch is having issues, kick out of gear on occasion sure, but slip.
But it seems like everyone with even the slightest sound or 'feel' is going to be rushing to their dealers now.....everyone keep us posted with what you find out

 

I have had problems simular to what you describe with my 2007 manual sahara and have been looking for someone who may be able to assist me with describing or providing information to my dealers service center for a problem I am experiencing. I have been to the dealer multiple times to have it checked but they never replicate it because it does not do it consistently. I have verified that it happens when I am at a stop and depress the gas, it will then pop or slip out of first gear. I am very frustrated. They have replaced the shift boot (Upper and lower) but will not go any further until they are able to replicate it. I am no where near a mechanic and could defintely use some assistance.

Has anyone explained in detail to you what was causing the issue you have been experiencing?

 

I believe this condition is caused by design. Mine does not grind from 1st to 2nd but actually wont even get it into gear. Feels like the solid contact stated by a poster above. I have to double clutch it to make it do a one, two shift. Most of the time i just skip the headache and start in second. Condition goes away when things warm up.

 

I have not personally experienced this, but a friend of mine is a Chrysler transmission tech and he told me that he's replaced a lot of them for this problem.

 

This morning was the first time I felt a grind going from 1st-2nd, and I thought about this thread immediately.

In this situation I was executing my shift at close to 4k rpm. In my opinion, the syncros weren't wanting to mesh at those rpms and it caused it to grind.

I should state that I typically never shift above 3k, and have never felt it previously.

That being said, the 6spd is very notchy, especially between 1st-2nd. I really think a short throw shift lever would make a world of difference here.

 

Mine does the same thing. Only when it's below freezing, and usually only the first and maybe second shifts. Some days I have to really work to find second too. I mentioned it at my first service in the fall and they told me "the notchy feel is characteristic of the JK transmission". Notchy feel maybe, grinding... I don't think so. I was going to bring it up again at my next service but that won't be until the spring after the weather warms up and they definitely won't be able to replicate it then. So I'm debating if I'll drop in at the dealership and complain again or wait until next winter after I have some more miles on it.