'85 Bronco II A4LD issues

[ford4wd08]

Hi all.

I have an '85 BII with the first year A4LD.

This means it is all vacuum controlled minus the TCC lock up solenoid (2 wire).

I recently performed the duraspark conversion to the 2.8 V6 which includes eliminating the computer and the lock up control provided by it.

I confirmed the transmission would drive 1st - 3rd no problem after I removed the computer.

A work around this is to install a 50 psi pressure switch in a boss at the rear of the transmission near the governor and tail housing.

I drilled and tapped the hole and mounted the pressure switch, and since then the trans will not up shift at all. I can manually shift it to 2nd, but it will not go into 3rd at all.

I pulled the transfer case and checked the governor yesterday, it seemed ok, I removed it and cleaned it and reinstalled it. Same symptoms.

When wiring up the pressure switch, I most likely put too much voltage across the solenoid trying to find a keyed 12 volt source. Could a burned up or non functioning solenoid cause these problems?

I'm not sure what else to do, trans worked great prior to the duraspark swap.

Here are some threads from other sites with more info to my swap.

85 A4LD and duraspark

I have a question for the transmission guys. Can you leave the computer in place to control the TC lock up on a 85 when you do a duraspark swap? Is that part of control independent of carb control? What does the comouter monitor to control TC lock up?

www.therangerstation.com

Pressure switch info --> A4LD Swap Pictures

I came to the explorer guys since all the BII and Ranger guys despise the A4LD lol, most Explorer guys learned to live with it.

 

[ford4wd08]

Anyone have any ideas?

 

[JK080]

Might want to try to install a pressure gauge where your governor pressure switch is to monitor governor pressure, no governor pressure no up shift.

 

[ford4wd08]

Might want to try to install a pressure gauge where your governor pressure switch is to monitor governor pressure, no governor pressure no up shift.

How much pressure should be there?

 

[BrooklynBay]

Check the vacuum line going to the modulator. Maybe it got unplugged. There's a service port with a plug on the side of the transmission. Use a 0 - 300 PSI test gauge. This port is a better place to put a pressure switch. The thread size might be the same as your pressure switch.

 

[ford4wd08]

Check the vacuum line going to the modulator. Maybe it got unplugged. There's a service port with a plug on the side of the transmission. Use a 0 - 300 PSI test gauge. This port is a better place to put a pressure switch. The thread size might be the same as your pressure switch.

Thank you for the reply. I was under the assumption that if if the modulator was bad it would be a rough shift into first or reverse?

I know it is not difficult to replace. I might just change it for piece of mind to begin with.

 

[JK080]

How much pressure should be there?

Governor pressure should kind of match road speed, zero pressure sitting still and as you pick up speed the governor pressure should rise.

 

[ford4wd08]

Governor pressure should kind of match road speed, zero pressure sitting still and as you pick up speed the governor pressure should rise.

If the governor is moving freely, could this be a modulator issue? I am thinking of replacing it anyhow because it is 35 years old. The rig only has 60k miles on it (no the odometer did not turn over).