TJ grinds when trying to shift into reverse

TJ Starting

TJ Starting

The Seven Slots of the World
Supporting Member
Joined
Jan 22, 2019
Messages
1,067
Location
SE TX
Just purchased my first vehicle yesterday, A rust free1998 TJ with 130,000. It's got the i6 with 5 speed manual, but I have only been able to get it in reverse a few times. It just wants to grind and wont pop in.The times i have, it works perfectly. All the other gears work pretty normal. Wondered if anyone knows anything about this.
76117
 
On my 6speed in the jk I sometimes had that issue, I found slipping the clutch just a touch while holding against whatever is stopping it from going into reverse would let it drop the rest of the way in

—
There must have been a time
when we could have said no.
 
  • Like
Reactions: billiebob
Hit fourth gear before reverse and it should pop right in. This works because 4th is syncronized so it lines up the gears.

Sent from my SM-G950U using Tapatalk
 
Reverse gear is not synchronized on your AX-15 transmission so shifting into Reverse without using the right technique will invariably cause the gears to grind. That right technique is nothing more than first momentarily shifting into any forward gear first then directly into Reverse. I usually shifted into 1st gear first before shifting into Reverse but you can shift into any of the five forward gears to accomplish the same thing. That technique serves to synchronize Reverse before you shift into it. :)
 
Last edited:
  • Like
Reactions: BLindzy, Flivver250, TJ Starting and 1 other person
I'm on my phone, but from what I can see it looks like you might have a body lift. That could be affecting it. My TJ has a t-case drop on it, about 1.5", which causes 2nd and reverse difficult shifts. I'm putting in an SS Sye, so I'll be removing that drop which should fix my shifts.
 
  • Like
Reactions: TJ Starting and Jerry Bransford
jeeper99 said:
I'm on my phone, but from what I can see it looks like you might have a body lift. That could be affecting it.
Click to expand...
That can affect how completely it can shift into some gears but it won't contribute to or cause gear grinding like the OP is having when shifting into his transmission's unsynchronized Reverse. Read post #5 above.
 
  • Like
Reactions: TJ Starting and jeeper99
As Jerry said, the "old guy" trick from us folks that have had to deal with finicky transmissions for years, is to "cycle it" through the gears 1st. My longtime habit is 1st, 2nd, then left & up for reverse. When I used to drive a dump truck for the County road crew, NONE of the gears were synchronized - the crew chief, and older Italian guy, said to me "Doob-la clutch-a, save-a you transmeesh-a..." ~40+ years ago and I can hear him saying that like it was yesterday, LOL...
 
  • Like
Reactions: TJ Starting and Jerry Bransford
Well thanks a lot for all the replys. And have tried a few different things suggested on here. And with much success! :giggle:
 
  • Like
Reactions: Blondie70
jeeper99 said:
I'm on my phone, but from what I can see it looks like you might have a body lift. That could be affecting it. My TJ has a t-case drop on it, about 1.5", which causes 2nd and reverse difficult shifts. I'm putting in an SS Sye, so I'll be removing that drop which should fix my shifts.
Click to expand...

Good eye! Checked it out and yes it does have about a two inch body lift
 
Jerry Bransford said:
That can affect how completely it can shift into some gears but it won't contribute to or cause gear grinding like the OP is having when shifting into his transmission's unsynchronized Reverse. Read post #5 above.
Click to expand...

I have this issue. My Jeep sometimes won't fully shift into 2nd or reverse when it's really cold until everything warms up. I've always done the first to reverse synco line up since I learned to drive, and that does the trick with lining things up. IIRC, the installation insturctions for my 3" BDS lift stated that trimming of the floor pan around the shifter might be necessary if using the t-case skid drop, which I had to use.
 
Daveh370 said:
I have this issue. My Jeep sometimes won't fully shift into 2nd or reverse when it's really cold until everything warms up. I've always done the first to reverse synco line up since I learned to drive, and that does the trick with lining things up. IIRC, the installation insturctions for my 3" BDS lift stated that trimming of the floor pan around the shifter might be necessary if using the t-case skid drop, which I had to use.
Click to expand...
Could be caused by either or a combination of a tcase drop and a body lift. Either can restrict the throw of the transmission shifter by increasing the distance from the top of the transmission to the shifter boot. Having both a body lift and a tcase drop increases that distance even more which further restricts how far the shifter can be moved.
 
  • Like
Reactions: Daveh370
billiebob said:
no, no need to trim anything. There is usually enough adjustment in the 2 plates which close the hole in the tunnel. Maybe ovalize the bolt holes with a file but there should be no need to "cut the hole bigger".
Click to expand...

Thank you for the advice. I'll give it a shot and see what happens.
 
Jerry Bransford said:
Reverse gear is not synchronized on your AX-15 transmission so shifting into Reverse without using the right technique will invariably cause the gears to grind. That right technique is nothing more than first momentarily shifting into any forward gear first then directly into Reverse. I usually shifted into 1st gear first before shifting into Reverse but you can shift into any of the five forward gears to accomplish the same thing. That technique serves to synchronize Reverse before you shift into it. :)
Click to expand...
I have a TJ 06 4.0 manual 6spd and having this issue will the same process work and is there a fix?
 
JoePal said:
I have a TJ 06 4.0 manual 6spd and having this issue will the same process work and is there a fix?
Click to expand...

i have a new to me 05 TJ with the 6 speed nsg370 transmission and the above does work for me quite well. However my transmission was made early enough in the 05 cycle that it does not have a synchro reverse. It is my understanding that they released a TSB for the transmission that added a synchro to reverse and that somewhere between 05-06 all nsg370 off the line came with a synchro reverse. Not sure where yours would fall.

Here is my thread and the replies:
https://wranglertjforum.com/threads...n-about-reverse-gear.37366/page-2#post-619267
 
  • Like
Reactions: Jerry Bransford
JoePal said:
Thanks So I don't know where im at with nsg370, what will work and if there is a fix. A lot of this goes over my head frankly.
Click to expand...
I’m no expert by any means, and I’m not sure there is a way to actually tell what version is installed.
I’m thinking that if yours has the synchro and it’s behaving this way then it could be a number of things, the reverse synchro itself, the fork, etc. a good video by high gear transmission goes over it here:
Either rebuilding the tranny or buying a rebuilt one is really the options, neither one is cheap and both are way over my head.

if yours does not have the synchro then you can live with it like I do. Install the TSB kit, which is hard to find, and not really cheap and labor intensive by my thinking or install a rebuilt one with the synchro.

I live with it because it’s technically working as designed imo, at least mine is.
 
appreciate the detailed response. its upsetting cause its running so well. the issue became an apparent monday after the transfer case drop. thanks for the high gear video, interesting.
 
Looks like because of the transfer case drop the center console is in the way. pulled off the outer boot and its going into reverse with out issue. hope thats all it is .
 
Top Bottom
Back