I had to replace my transmission, automatic
The new one works but does not self shift,
How do I fix it meself?

 

1990 4.0l will have an A4LD 4-speed with electronic controlled Torque converter and 3rd/4th shift.

There will be 3 wires connected to a D-shaped connector on the side of the transmission.
1 wire will have 12volts with Key On
Other 2 go to the computer, one locks torque converter, the other shifts the OverDrive(OD), the 3rd/4th shift.
But that's all it controls

Transmission in Drive should shift on its own from 1st to 2nd and 2nd to 3rd, if that doesn't happen then you have internal problems.
Automatics work on pressure, and higher RPM = higher pressure, when pressure gets high in one gear valves open and it shifts to the next gear, no shift means either valves are stuck or gaskets are leaking(no pressure build up).
But trans needs to come out in any case.

If the replacement trans was a rebuilt then it will be under warranty, if it was a used transmission you bought someone else's problem.

Good read here on A4LD:

 

I have a question:
My tranny has 2 air vents, should they still be connected?

 

There is a "vent" on the top side toward the rear, it should have a metal tube running across the top and then loop back to bell housing.
Picture here of Vent, Green circle: Ford Transit Forum ? View topic - A4LDe Autobox

On the Passenger side there is a "Vacuum" hose hook up, it should have a rubber vacuum hose running up to engine and then hooked to intake manifold
In above picture, just below the end of the green arrow you see a gold part, that's the vacuum modulator

Neither of these would cause the "no shift" problem

 

Thank you.

 

Are the bands suppose to be snug or loose?

 

Google: automatic transmission bands adjust

 

Thanks

 

I have a question?????????????????????

Can I put a tranny from a 98-02 Ford Ranger into a 90 Ford Ranger if I change the bell housing???

 

Yes and no.

First, on an automatic swapping bell housing is a complete rebulid, and it must be from same model trans, on most.

Second, '95 and up transmissions will need a computer to operate that model.

'90 A4LD just had 2 controls and OBD I(EEC-IV) computer, '98 and up needs a computer with more controls, it is also a OBD II(EEC-V) computer.

So yes, if you get a OBD II computer for '98 and up transmission(also must be for your engine size), and add some sensors OBD II requires that OBD I didn't, extra O2, Crank position, cam position, probably others I can't think of.


And no, if the above seems like a pain in the a$$, it does to me.

 

Thanks