Auto Tranny - Lost OD
 

New to the forums...and, frankly, to pickup trucks. I've brought an abandoned '86 Pickup back to life but I'm still working out some issues.

22R engine, auto tranny. A few weeks back I replaced the AT fluid/filter and everything was fine until a few days ago. It does not shift up into OD anymore. L to 2 shift is smooth as silk, 2 to D shift is a little harder, and D to OD never happens no matter what I do. I've turned the OD switch on and off to no avail. Fluid level is ok, I've topped it off without overfilling but that didn't help. There is also a buzzing noise coming from somewhere that stops as I am adding trans fluid, then resumes.

Any ideas? Thanks.

Anyone?

I've searched the forums but didn't see anything quite like what I describe. I'm afraid I might lose D next because the 2 to D shift has gotten steadily worse over the past few days.

The ECU will keep the tranny from shifting into OD if it detects the coolant isn't hot. If you're lucky, it will just be something like that. Wishing you luck.:)

If you don't get lucky, I think I'd pull the valve body out and either send it to IPT for testing/inspection/cleaning OR try testing the shift solenoids myself. (not sure how to test them though) I've heard that things as small as lint from a rag can cause shift solenoids to malfunction.

Oh heres the link for IPT: http://www.importperformancetrans.com/downloads.shtml

If you do remove the VB make a little map of which bolts went where because there are 3 or 4 different lenghts and it does matter where they go.

mine did that once. I had the tranny flushed and it quit. Also,
thermostat may be bad.

I was planning on replacing the thermostat soon anyway (the engine takes quite awhile to warm up). I hope I get lucky too...

I'll give that a try.

Have you checked to see if the OD light will flash a code?

I've done a search and found many threads talking about "my OD flashed code XX", but I couldn't find anything telling me how to get the code to flash. Is there some method to make it flash, or does it flash automatically whenever it senses a problem?

It's certainly not flashing automatically...the light comes on when I turn the OD switch to OFF, and goes out when it's ON.

Yeah you have to jumper a couple pins in the diagnostic plug under the hood. Sorry I can't remember for sure which pins it is.

I'll try the thermostat first. The less I know about the automatic tranny, the better :D I'm planning on doing a engine/tranny swap in about a year, so I just need to keep the thing running for now.

Oh, and about that buzzing noise...any ideas on that? Think it might be related? I see some folks have had an issue with some heat sheild vibration causing a similar noise, but the fact that the buzz stops as I add fluid makes me think it's a different problem (I assume there is some sort of AT fluid pump?)

How often are you having to add fluid? How long after you add fluid before the buzzing starts up again?

Here's the "pulling the codes" info:
http://www.4crawler.com/4x4/CheapTri...CheckConnector

How's the color on the atf?....red...pink....tan...dark brown?

I've only been adding a little fluid at a time thinking that when I replaced the fluid I didn't quite fill it up to capacity. I can't find any evidence of a leak.

The buzzing resumes literally seconds after the last of the fluid has run down the fill tube. It may just be coincidence that it stops as I'm adding fluid...it doens't make the noise Constantly, but fairly consistently.

(and thanks for the link....good stuff)

The color looks pretty good...reddish with just a slight brown tone. When I changed the fluid I didn't completely flush the system (quite a bit stays in the tq converter etc even when drained completely). I've probably driven 300 miles since the change, so it may be too early to tell if the color is way off.

vibration could be the dipstick vibrating on side of transmission pan.

Or maybe where the 2 sections of fill tube fit together. There is suppost to be an o-ring there maybe you lost it.

That sounds plausible. If there was ever an o-ring there I'm sure it disappeared sometime during the first Bush administration.

Either way sounds like you guys don't recognize the buzzing as any obvious mechanical issues.

Mine buzzes from time to time. Nothing that's ever really concerned me.

Hard to guess without hearing it.

This is how to make the OD light flash a code. Look for a square plug behind the air filter/AFM box. Ground this plug. The FM shows a volt meter, just stick a piece of wire in it and ground the other end.
http://i22.photobucket.com/albums/b3...4RUNNER005.jpg

Then push in the OD button, switch the ignition to on, don't start. The OD ligth will flash a code. Here are the codes.
http://i22.photobucket.com/albums/b3...4RUNNER447.jpg