4lo won't engage, stays in 4hi

rvmccarthy · Nov 23, 2012

92 Jeep NP231

4hi and 4lo have always worked just fine. Went to use 4lo the other day and the TC stayed in 4hi. When shifted into 4lo it stays in 4hi.

I shift into 4lo by stopping, putting transmission into neutral, shift TC down to 4lo.

I readjusted the shift linkage, and the TC fluid is clean and clear. 4hi works just fine, even if shifted into 4lo.

It's always been a little bit difficult to pull the level down into 4lo, but it's never made any grinding noises or anything like that.

Anyone got any ideas?

Thanks!

in4aride · Nov 23, 2012

Can you manually shift the case into low(as in by under the jeep moving the linkage directly on.the case)?
If yes. Its not adjusted correctly.

sidewaysstarion · Nov 23, 2012

Will the tcase shift into neutral?

weebur · Nov 23, 2012

How did you adjust the linkage? If you didn't do it this way you might want to try it:
Pull the lever all the way back into 4L, have someone hold it back or tie it back with rope. Loosen the screw on the trunnion, make sure it slides free then tighten it back up. Test.

rvmccarthy · Nov 23, 2012

I cannot shift it into 4lo at the TC. The shifter will move into position to be 4lo, but it stays in 4hi.

This is what happens when I shift. from 2wd it shifts into 4hi on the fly just fine. Stop, put vehicle into neutral, shift TC into neutral (that works), pull lever back for 4lo, instead of going into 4lo it goes into 4hi. I have tried doing it while the vehicle is barely rolling, as well as rocking it back and forth. It's like someone replaced my 4lo with another 4hi.

I adjusted the linkage based on a post here on NAXJA

. Basically exactly what you described, I left the 1/8" space.

weebur · Nov 23, 2012

It sound like you're doing everything right. When you tried shifting into 4L at a slow roll did you hear/feel gears grinding? I'm going to try and send you a PM.

rvmccarthy · Nov 23, 2012

Nope. In fact, it shifts into the 4lo position easier now than it did before. When put into 4lo it drives and runs just fine, except instead of being 4lo it's in 4hi.

Very frustrated!

weebur said:
It sound like you're doing everything right. When you tried shifting into 4L at a slow roll did you hear/feel gears grinding? I'm going to try and send you a PM.

87manche · Nov 23, 2012

possible that somehting has happened to the mode fork in the case. You're probably taking it apart and having a looksy. Get some new teflon pads, they're always destroyed and can be the cause.
Otherwise I'd suspect that the fork is broken/bent and not moving the collar all the way.

weebur · Nov 23, 2012

rvmccarthy said:
Nope. In fact, it shifts into the 4lo position easier now than it did before. When put into 4lo it drives and runs just fine, except instead of being 4lo it's in 4hi.

Very frustrated!

There may be a clue here. When you're at a very slow roll and you try to shift into 4L you should hear/feel the gear teeth trying to mesh. The fact you don't feel it may be an issue.

rvmccarthy · Nov 24, 2012

Well, I don't know what happened. I had to drive a short way on a gravel road and threw it into 4lo to see what happened. Worked just fine.

Good thing too because I don't have the cash to rebuild it. lol Hopefully that wasn't the beginning of the end for it.

4lo won't engage, stays in 4hi

rvmccarthy

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in4aride

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sidewaysstarion

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weebur

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rvmccarthy

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weebur

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rvmccarthy

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87manche

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weebur

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rvmccarthy

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