a4ld Trans Problem

[Hurm2006]

My dad has a 4X4 1990 Ranger with a 2.9 and the a4ld trans. He rebuilt it about a year ago and it worked great up until about a month ago. the speedometer is not right most of the time the cruise quit working and at 50-60 mph it constantly shifts between 3rd and 4th. Was wondering what could cause this?

Matt

 

[MrShorty]

In 1990, the 3-4 shift on the A4LD was electronically controlled. I would start by checking those electronic controls (especially where the cruise went out about the same time, since they both share a few common elements).

1) Pull codes from the computer. See my notes on pulling EEC-IV codes.
2) Once all codes are resolved, if the problem still exists, then test if the computer can command the 3-4 shift. Put a voltmeter across the solenoid then enter the output state test mode and see if the computer can switch the circuit.
3) Driving test, still with the voltmeter across the solenoid. See what is happening electrically when the transmission is shifting in and out of 4th gear.

 

[Hurm2006]

while taking the trans out he took the vaccum hose off of the vaccum module and there was trans fluid in the hose. Could this cause these problems?

Matt

 

[BrooklynBay]

Welcome to this forum! The modulator is bad, but that is only part of the problem. The PCM is not getting a speed signal to tell it to go into overdrive.

 

[Hurm2006]

he changed the vaccum module and the speed sensor and the same problems occur: shifting from 3rd to 4th constantly, speedometer not right and the cruise don't work. Any other suggestions?

Matt

 

[BrooklynBay]

Was the gear on the end of the VSS, and inside the transmission checked for any damage? Do the speedometer, and transmission shift erratically when you tilt the steering column? I read about this kind of problem in Gears magazine. It was found on a Ford motor home.

 

[Glacier991]

While cruise controls can fail for quite a number of reasons (bad amplifier, etc) when you lose cruise control and start having shifting problems at the same time, as others have pointed out, you look for a common connection between the two - in this case the speed sensor. BrooklynBay is giving you excellent advice here. Still suspect the speed sensor or its wiring. But as others have said also look for codes. Keep us posted.

ps. I moved this to the transmissions forum where it will get wider exposure.

 

[peties3]

i had a problem that the rear output yoke on the transfer case was loose allowing the gear inside to slip. erratic speedo and cruise control problems.