Crunchy shifting, jumps out of second

[tjryder]

Hi,

I have a 1999 4.0 manual TJ.

It has not been driven much 136.000kms.
- when cold in the morning it grinds when shifted from 1.st to 2.nd. Oil has been changed less than 2.000mls ago to factory specs.
- when warm - occasionally jumps out of gear when shifting at low speeds from 3.rd to 2.nd

I have had different oppinion on reasons - from oil, warn synchro to bent shifting fork.

Anny oppinion / experiance with this kind of issues?

Thanks!

 

[PatMc]

Jumping out of gear is typically indicative incomplete engagement. This could be due to an internal issue like a worn syncro hub or slider...possibly even a damaged syncro ring or slider key that not allowing complete engagement, or it could be as simple as a sagging or broken trans mount or some sort of damage/nonsense that is causing the shifter to hit something before it can travel far enough to fully engage the slider on the hub for the gear you've selected. Bent shift fork is a possibility too.

I would start by pulling the console and all the shift boots out and making sure the shifter isn't hitting any sheet metal, then pop the shifter out and make sure the shifter bushings are in good shape...if not, change them and try again.

Incorrect oil will cause difficult shifting, but not popping out of gear. Popping out of gear is due to incomplete engagement.

 

[tjryder]

Hi,

Thanks for reply. Jumping occurs usually when trning left or right during downshift. Middle of crossroad typically....

Shifting is smooth when gbx realy warm. When cold it crunches. Could this be related?

 

[PatMc]

What type of oil did you use?

Does the shifter feel fairly firm and gated or sloppy like an old VW aircooled shitbox?

 

[tjryder]

Shifter follows the pattern firm. Perfectly stays in (jumps in!) in 3, 4, 5.

 

[PatMc]

oil?

 

[Goatman]

New Oil can make cold shifting difficult. After it breaks in then cold shifting improves. Odd, but true. But it seems to happen selectively. Some trans do this while others (same model) don't. Bent forks can cause it to jump out of gear. You didn't say if this started with the new fluid or has been an ongoing problem.
I'd pull the shifter boot to confirm there is no external interference. An old trans mount could be involved. Or even a motor mount, since it happens while cornering, allowing the drivetrain to shift or roll pushing the shifter against the tub or something. As for popping out of gear during a downshift...it is supposed to come out of gear during a downshift.
Switching to a slightly thinner oil may help the cold shifting problem. From a 85/140 to a 75/85 or similar. A lot of people (me included) have had amazing results switching to Redline brand fluid in the trans.

 

[tjryder]

Castrol 75w-90
I have had a 1997 4.0TJ before and did not have the issue.
After i switched to next TJ - this problem apeared.
In both cases I did fluid change immediatly after purchase as you newer know with used vehichle. Exactly the same oil.