mtyson

'97 i6 aw4 4x4

I replaced the 1-2 and 3rd solenoids on this jeep about 2 years ago when it stopped shifting manually into 1st.

Now it has started failing to shift to 3rd. You'll be driving and it'll just drop into 2nd and rev instead of shifting to 3rd.

After turning it on and off a few times/letting it rest, it will start working again.

The problem is becoming more frequent.

Help.

mtyson

So this problem is definitely getting worse.

I am thinking mechanical because it seems to happen randomly and then after enough restarts/time at rest, it will start working fine again and then for a while, even a half a day, it will drive as though nothing is wrong at all.

Notice the trans fluid is slightly dark/burn smelling, however. Trans service indicated?

Any leads on where to start troubleshooting greatly appreciated.

s346k

maybe verify that the neutral safety is clocked correctly. if the fluid is dark and smells burnt i’d do a drain and fill just to get an idea of how bad it is.

dans98xj

it may not be mechanical. Under the dash on the drivers side next to the gas pedal there is a box about the size of a deck of cards unplug that. It is your TCM. After unplugging it start it up and take it for a ride, you will have to shift manually though the gears It will start in 1st and skip 2nd go to 3rd and OD. There will be no torque converter lock-up either, so don't drive too long. if this get the trans in 3rd then that is a good indicator of the TCM being bad. I would also do what s346k stated as well.

mtyson

I still have the TCU plugged in, but I put it in 1-2, and noticed that it won't shift into 2nd when in 1-2.

It shifts into 2nd when it is in D, but then won't go into 3rd.

dans98xj

it will only shift in 2nd in the 1-2 position at about 4500 rpms.

mtyson

It consistently works properly in the morning before it is driven. So it seems to be something that is worse when the car is warm.

mtyson

If its electrical, where should I be looking?

Solenoids, even though they are only a couple years old?
Trans speed sensor(s)?

I'm going to try unplugging TCU today. Sounds like shifting from 1 into 3 is the only trick?

As always, God bless the cherokeeforum.

mtyson

Also, what is this TCC solenoid, appears to be different from the shift solenoids. Where does this guy go?

mtyson

Could the NSS be involved in this problem???

mtyson

OK, summarizing my questions:

Transmission shift solenoids: there are 3: 1-2, 3, and OD

Is OD same as TCC (Tran. control) Solenoid? Is this also the lockup solenoid?

Could the NSS switch be involved in this problem?

Sorry for spam, trying to understand.

dcollins3208

-there are 3 solenoids. S1 & S2 control 1-2, 2-3, and 3-4. S3 is tcc lockup only.

-NSS is certainly a possibility.

-FSM calls for you to unplug the transmission control module and shift manually, as someone mentioned earlier, to rule out mechanical vs electrical. With TCU unplugged, you use the gear selector to shift from 1, 3 and OD. You will NOT be able to shift into second unless you rev to about 4500 rpm in 1st. As soon as your issue happens again, that would be a great time to unplug the TCU and test. If your transmission does not shift correctly in "manual" mode, then your issue is mechanical, internal in the transmission and it will need to be R&R'd.

mtyson

Beautiful THANK YOU.

What's happening now is the jeep was driving normally, so I checked the TCU anyway, to make sure I knew where it was. I unplugged it and plugged it in.

Guess what... since then, the shifting has been perfect.

So maybe that was loose???

Hopefully so.

I'll update here if it starts up again.

Thanks again you guys.

mtyson

So it has been doing better, but last night it declined to shift into 3rd a couple times...

Removing and plugging in the TCU didn't seem to help, but fiddling with the wires and connectors around the tranny itself DID seem to remedy it.

So I am thinking NSS replacement? It looks original and a bit fried. Also, there is a lot of oil down there on things...

another q: What is the wires/connector I can feel going to the top of the transmission? Feel but not see???

Thx!

dcollins3208

You have to leave the tcu unplugged to do the manual shift test.

Wires are probably for the solenoids