92 A4LD slips when cold and no overdrive

[taylor0987]

Hi, I have a 92 Navajo 4wd with the A4LD transmission. When it's cold it slips, takes 30 seconds or so to get into gear, or it will sometimes go into gear when I rev the engine. It has this problem regardless of what gear I select (R, overdrive, D, 2, or 1) When it's warmed up it behaves normally except that it will never shift from 3 to overdrive.

The fluid level is correct. I changed the fluid and the filter. It did have a delayed 1-2 shift and I already pulled the governor and cleaned it. That seemed to help some. I have not tried adjusting the bands or much else of anything. I have read alot here on the forum but I'm not sure where to start given my symptoms.

I do not know much else about the history of this vehicle--I bought it for cheap with the engine blown and swapped in a junkyard engine, and have had these problems since I got it running.
Thank you.

 

[Glacier991]

Well, there could be a number of issues.... Valve Body would be a good start. Once it is warm it shifts ok ?

 

[taylor0987]

Yes, once it's warm it shifts pretty well, except that it will not go into overdrive-- i only get the 1-2 and then 2-3 shifts. It downshifts when I floor it.

 

[BrooklynBay]

I would suggest checking/replacing your vb gaskets, and cleaning out the vb. Check the continuity of the OD solenoid, and wiring harness for a constant V (+). Check the internal harness as well. The internal harness has a built in diode, so keep in mind that a diode only conducts electricity in one direction.

 

[taylor0987]

If there are transmission codes, would I be getting a check engine light?

If I remove and clean out the valve body, should I be replacing anything else besides the gaskets?

Do I want to have continuity on the 3-4 solenoid or not? In the service CD it says I want 20 Ohms at pin 52 but is that with a breakout box (something I don't have) Should I remove the harness from it when I test for continuity? Am I just checking for continuity or something else on the internal harness, or is there somewhere on the ford service CD that tells what to test for?

Thanks very much.

 

[MrShorty]

If there are transmission codes, would I be getting a check engine light?

that would be a definite maybe. Only way to know for sure would be to pull codes. There aren't very many possible transmission codes with an A4LD, and those codes, when they do occur, are almost always either a full open or a short to ground in the offending circuit.

If I remove and clean out the valve body, should I be replacing anything else besides the gaskets?

Do I want to have continuity on the 3-4 solenoid or not? In the service CD it says I want 20 Ohms at pin 52 but is that with a breakout box (something I don't have) Should I remove the harness from it when I test for continuity? Am I just checking for continuity or something else on the internal harness, or is there somewhere on the ford service CD that tells what to test for?

Thanks very much.

Breakout box is a tool that allows you to test various circuits while minimizing the risks of shorting or otherwise damaging the 60 pin connector or the computer. If you are careful, you can do the same tests by backprobing the 60 pin connector. One thing to be careful of -- Unless specifically told to do so, don't have the computer plugged in when measuring resistance of a circuit. At best it can throw off your reading. At worst you can damage the computer by attempting to measure resistance.

 

[taylor0987]

Breakout box is a tool that allows you to test various circuits while minimizing the risks of shorting or otherwise damaging the 60 pin connector or the computer. If you are careful, you can do the same tests by backprobing the 60 pin connector. One thing to be careful of -- Unless specifically told to do so, don't have the computer plugged in when measuring resistance of a circuit. At best it can throw off your reading. At worst you can damage the computer by attempting to measure resistance.

thanks, I was asking before doing it exactly for the reasons you give... do you know if the 3-4 solenoid should be d/c or not before testing for continuity? As I said I don't have a breakout box. I don't think I need to test at the 60 pin connector since I will have the trans pan off to pull the vb and the 3-4 solenoid is right there.

 

[BrooklynBay]

The solenoids do have resistance, and they are only on/off devices. I would suggest checking them directly when you remove the pan. Unplug their wiring, and check them directly to get an accurate reading. Then after doing this, carefully unplug the vehicles wiring harness going to the case's connector, and check that harness for continuity. Keep in mind that there is a diode in that harness, which only conducts electricity in one direction. You could spray out those 2 solenoids when you remove them with the 12 volt "click" method as described in the rebuild diary.