Driving with no OD Lockup ?

So my Trans won't lockup in OD
Will it hurt it to drive it this way ?

Nope. You can pull the fuse/unplug the TCU and drive it manually if you want.

It won't hurt it. Check to make sure your NSS (Neutral Safety Switch) is clean. This is a very common issue.

the_weirdo said:

It won't hurt it. Check to make sure your NSS (Neutral Safety Switch) is clean. This is a very common issue.

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I have tried everything, I have another thread about the issue.
But for now I give up and just want to drive it to get out and play
in the Snow.

Hate to hijack, but here goes. While on the subject of the NSS, does the cruise control circuit depend on a switch or contact in the NSS? I know the switch in my '92 is dirty, reverse lights almost never work. Occasionally I need to jiggle the shifter to start it. The cruise works intermittently. Sometimes pulls in nice, sometimes pulls in weak, then cuts out, sometimes won't engage at all, especially if the headlights are on. I haven't had it out much for the last three years, so it's hard to see a pattern.
Once again, sorry about the hijack.

Back on topic. I was under the impression that driving a lock-up TC vehicle un-locked for an extended time will build up heat that the tranny wasn't designed to tolerate. If this is going to go on for any period of time, I hope you have an auxiliary cooler to help the fluid dissipate the extra heat.

heyhar said:

I was under the impression that driving a lock-up TC vehicle un-locked for an extended time will build up heat that the tranny wasn't designed to tolerate. If this is going to go on for any period of time, I hope you have an auxiliary cooler to help the fluid dissipate the extra heat.

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I have the factory Cooler

heyhar said:

Hate to hijack, but here goes. While on the subject of the NSS, does the cruise control circuit depend on a switch or contact in the NSS? I know the switch in my '92 is dirty, reverse lights almost never work. Occasionally I need to jiggle the shifter to start it. The cruise works intermittently. Sometimes pulls in nice, sometimes pulls in weak, then cuts out, sometimes won't engage at all, especially if the headlights are on. I haven't had it out much for the last three years, so it's hard to see a pattern.
Once again, sorry about the hijack.

Back on topic. I was under the impression that driving a lock-up TC vehicle un-locked for an extended time will build up heat that the tranny wasn't designed to tolerate. If this is going to go on for any period of time, I hope you have an auxiliary cooler to help the fluid dissipate the extra heat.

Click to expand...

Might be vacuum issues on the cruise, check all of the vacuum lines and don't forget the brake switch.

Hylander said:

I have the factory Cooler

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The factory auxiliary cooler, as in Towing Package, or just the coil in the radiator? The best thing to do is figure out how to make the lock-up work again. It'd be a shame to overheat the tranny and ruin it if it could have been prevented. I don't know if a new AW4 would fit in Santa's bag.

joe_peters said:

Might be vacuum issues on the cruise, check all of the vacuum lines and don't forget the brake switch.

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The vac. lines are fine, I've traded the servo with two known good units, plug is clean, under the hood seems all good. I was just taking a stab at the NSS, as it's time to get one from the yard, clean it up, trade it, clean, lather, rinse, repeat, etc. We have four XJs, and all need a shifter jiggle from time to time.

Does the cruise work from the brake light switch, or does it have its own?

heyhar said:

The vac. lines are fine, I've traded the servo with two known good units, plug is clean, under the hood seems all good. I was just taking a stab at the NSS, as it's time to get one from the yard, clean it up, trade it, clean, lather, rinse, repeat, etc. We have four XJs, and all need a shifter jiggle from time to time.

Does the cruise work from the brake light switch, or does it have its own?

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Should just work from the brake light switch. If your brake lights aren't working then the cruise shouldn't work either. The NSS wouldn't effect the brake lights, only the backup lights.

The brake lights work fine. I had a wild idea that the cruise used the NSS to determine if the car was in the proper gear to operate. The funny thing is, it works fine on a warm, sunny day. Here in PA, good luck! Almost never works if the headlights are on, sometimes if the heater blower is full whack, real cold day. It improved somewhat when I removed the 10 pin headlight plug at the radiator bulkhead, very corroded, and soldered the wires. Maybe the electric wires to the servo find a ground where the lighting harness is grounded? Maybe I have a new project.

About once or twice a year, mine would also fail to lock-up. It was noticeable once I got on the Interstate. Usually I pulled over in a safe place, put it in Park, shut off and re-started the engine, proceeded on my way, working fine. So, it may be the dirty NSS, and just cycling the shifter would have caused it to work again.

Doesn't anyone make a good twenty-year-old car anymore?

heyhar said:

The factory auxiliary cooler, as in Towing Package, or just the coil in the radiator? The best thing to do is figure out how to make the lock-up work again. It'd be a shame to overheat the tranny and ruin it if it could have been prevented. I don't know if a new AW4 would fit in Santa's bag.

Click to expand...

Factory tow package Cooler, seperate from radiator.
What are the vacume lines and where is this Servo you speak of ?

The Cruise Control servo is the 'motor' of the cruise. It's about 3" diameter, electric plug and vacuum fitting on one side, and a cable to the throttle coming out the other. If you have Cruise, you'll see three cables coming from the throttle body linkage, crossing over the valve cover. One is from the go pedal, another goes down to the tranny, and if you have it, the last goes to the cruise servo. (Servo is a fancy name for vacuum motor. It's easier to type, with only five letters!) The servo is mounted in different places, sometimes depending on options-ABS, etc. On my '92, it's on the driver side, just forward of the master cylinder. On most others, it's on the pass. side, near the Power Dist. Center.

Back on topic. See if you can figure out the problem. Is it possible your brake lights are stuck on? I've had cars-mostly Fords-with malfunctioning brake switches, and your first clue-without actually standing behind the car and watching the lights-would be something like the TC failing to lock or unlock. I think the Jeep also controls TC lockup and cruise with the brake switch, but I'm not sure. Whatever you find, please post up with it. This is getting interesting.....

Thanks heyhar:
I do have Cruise control and it works fine.
Brake lights seem to work fine and I have tried the lifting the brake peddl trick, is there an adjustment for that brake switch ?

I,m gonna hafta look.

Can the Speed Sensor effect the OD Lockup ?
Also can Heat effect it ?

I ask because I can drive all over town with no issues.
I have been driving around town for two days now and Freeway less than 10 miles at a time and it is still shifting fine.
as long as my temp gauge stays under 210 all is well.
However if I drive say 20 miles Freeway or the temp gauge stays 210 or alittle over is when I loose OD lockup.

If my fluids lines or cooler were plugged, it wouldn't shift at all would it ?