My EX died on me twice today when I put it in reverse. Once at the doctors office and once in my driveway when I got home. Is there any sort of interlock that would cause it to die when I put it in reverse. I replaced the idle control servo not long ago so I am hopeing it is not that although with the crap parts coming from China it is not impossible.

Perry

 

Low transmission fluid can cause this.

 

Thanks Mark I will check the fluid. I had a leak in the trans cooler a while back and I thought I fixed it. Maybe it came back. I have not seen a puddle though. It did it the first time when I was on a steep incline. So how does the low fluid stall the engine, abrupt clutch engagement?

Perry

 

Low fluid reduces the pressure that keeps the torque converter clutch from applying. When the pressure dips the clutch drifts on.

 

Yeah that would sure make it stall then. So the clutch is normally locked? Locked when no there is no pressure?

Perry

 

There are two pressures in the torque converter. Charge pressure and release pressure. When charge pressure is higher than release pressure the converter clutch is locked. When the converter is starved for pressure release pressure drops before charge pressure.

 

Well it is just even with the bottom of the dip stick with the temp around 150F. So it is a little low. I will add some and see if the problem goes away. It happened two of three times today.

Perry

 

Well I added a pint to the transmission. It was even with the bottom of the normal range when I added fluid. So I am guessing the problem is not that it is low on fluid. It only seems to do this when it is hot and only when I put it in reverse. I am getting worried at this point. I pull a trailer with this thing. I imagine that trying to back up a trailer with the transmission doing this will be beyond fun.

Perry

 

Add a bit more fluid. You want it in the middle of the range.

 

So if I add more fluid and it still stalls then what's next? Look for a loose inlet filter? The transmission has been getting better and better since I changed the fluid a while back.

Perry

 

Either check for a loose filter or get a pressure gauge and see what pressure is at the test port when it's stalling the engine. Low line pressure could mean a worn pump.

 

Those were my symptoms when the fuel pump went out. Stall in rev. or just putting into drive. After 1 month of this, it stopped all together. Can you say procrastination?

 

I checked the fluid last night and it was at the top of the cross hatch. If the pressure were low would there be any other symptoms? I will check the filter when I get a chance. If this thing going to just die one day or is it ok the drive like it is? What pressure is nominal at the test port? I assume some drop is normal but what is the min it can be? Can you tell me where to look for the test port? Do you know what the thread is on the port. I assume it is some sort of metric size and not NPT?

Perry

 

The port is 1/8" NPT dryseal. It is on the driver's side of the trans, towards the front of the trans, just above the pan rail.

I don't have a pressure chart. You should be able to find one with a search. Make sure you fine one for your transmission, the 4R100. There are different pressures in each gear.

Low pressure shows up first as a stalling issue in reverse. If it gets worse you'll get stalling in drive, then shift issues. It may or may not get worse.

 

Well at least it will be a gradual thing. I plan on doing some short hop trips pulling the trailer this summer. I am hopeing it is a loose filter. The pan was clean as a wistle but the fluid was brown when I changed the fluid not long ago. Thanks for your help Mark I will let you know what I find. If I don't find a filter issue, I will work on the pressure sensor. I may be able to find a pressure chart in the shop manual somewhere but I have not seen one so far. Do you know the range of the gage I will need? I maybe able to cobble something together with some stuff I have at work.

Perry