Bronco II with issues

[srmauer]

I recently bought a 1989 Bronco II 4x4 with several problems-the worst being the trans. When cold, the stock A4LD shifts out normally then soon after starts hunting between the top three gears. Serviced, adjusted bands, and replaced vaccuum modulator valve. What else could it be? I'm thinking of going into the valve body.

 

[BrooklynBay]

Welcome to this forum! My first thought was the modulator, but that was already replaced. A sticking governor usually acts up when its cold to cause a delayed 1-2 shift. It might be the beginning of a governor problem. How many miles do you have? When was the last time the fluid, and filter were replaced? You could have dried out servos causing a pinch off affect when the band applies. The band applies, but lacks holding pressure to maintain a positive grip, then gradually releases.

 

[srmauer]

The odometer shows 85,000 miles. How many times around, I don't know. I just recently changed the fluid and filter with no improvement. I do Know the truck sat for about a year before I bought it. Can I repair the servo when I pull the valve body for a v/b rebuild.

 

[MrShorty]

Exactly which "gears" are the three top gears? The A4LD is a 4 speed automatic with a locking torque converter clutch (TCC). My first thought when you say "top three gears" is that you are referring to "3rd gear unlocked->4th gear unlocked->4th gear locked". 3-4 shift and TCC lockup are both electronically controlled. If these are indeed the "shifts" that it's hunting through, I would check the electronics (pull codes, check wiring).

 

[BrooklynBay]

The servos I was referring to are located on the passenger's side of the transmission. The catalytic converter is in front of them, so they are difficult to replace, but not impossible while the transmission is in the vehicle. The only servo which is accessible from the bottom of the transmission is the low/reverse servo. I don't think this one is the problem.

 

[srmauer]

Seems like I'm kind of vague with the info. Sorry. When in reverse and accelerating, it feels as if the trans. is jumping in and out of gear. Not slipping-just a rapid in and out like a chatter. Under light acceleration reverse is fine. Now for Drive. I am not reaching overdrive. My "top three gears" are actually 2nd and Drive. At speeds of 45 or so Drive is ok. Above 45 and above it will shift from second to drive and back about every 3 to 4 seconds.