No Overdrive & Check Engine Light is on ?

[Hylander]

This is a confusing statement.

If you manually shift to 3rd, will the TC lock again?

What happens is it shifts from 3rd to Drive fine, but does not Lockup.

 

[kastein]

This info comes from my '98 FSM, so it may be wrong for your year, but you should be able to tap into the dark blue wire with a white stripe anywhere between the TCU and the transmission and feed the transmission 12 volts on this wire. This *should* lock the TC, if it does not, you have a bad solenoid (again!?) bad wiring anywhere between where you tap into the wire, or a problem in the valve body / transmission hydraulics.

 

[Digger87xj]

This info comes from my '98 FSM, so it may be wrong for your year, but you should be able to tap into the dark blue wire with a white stripe anywhere between the TCU and the transmission and feed the transmission 12 volts on this wire. This *should* lock the TC, if it does not, you have a bad solenoid (again!?) bad wiring anywhere between where you tap into the wire, or a problem in the valve body / transmission hydraulics.

This.

And to add; the TC itself can be and is likely bad.

 

[Hylander]

This.

And to add; the TC itself can be and is likely bad.

If the TC itself is bad, why would it work fine until Temps raise
to above 210 ?

 

[JJacobs]

Hot fluid is thinner?

 

[BalefireX]

An update on my similar issue:
I replaced the NSS and cleared the code. I now have reverse lights and overdrive is working (before the replacement, I just had 1st-3rd).
I've only put about 50 miles on since the replacement, but it seems to be working well so far.

 

[Jackhill442]

There is a switch on the brake pedal that engages overdrive. Drive it at 50 mph, with foot on gas constant, push brake slightly. If rpm does not change, this switch is problem. Also, buy a brand new NSS

 

[JJacobs]

Actually the brake pedal affects torque converter clutch application, not overdrive. People seem to be confusing the two in this thread. Overdrive is another gear, the converter clutch is not. It justs eliminates internal slippage in the torque converter while maintaining the same gear be it 3rd or overdrive.

 

[Hylander]

Just to Clarify:
I have OD, But sometimes the Converter Clutch will not Lock Up and I get the CEL.
I read on another thread that a guy overfilled the Fluid and got the same issue. Drained it to normal level and problem Cured.
I just checked my Fluid at engine running temp of 210 and I'm atleast 1/3rd of an inch over the Max Line, so tomorrow when it is cool I will drain a quart out and see what I get.
By the way with the weather a little cooler the Trans is shifting fine
and no CEL.

 

[Jackhill442]

Come to think of it Jacob, you are correct. The Jeep does still rev lower in 4th, but the converter isn't engaging fully. I would imagine it is bad for the trans to drive in this situation, right?

 

[Hylander]

Well I lowered the Fluid level to normal and no Joy :bawl:
I guess I'm stuck driving without T/C Lockup :gonnablow