I'm running out of ideas.
'83 AOD behind a 302, with a 3.08 rear end. No previous history known, but does not look like abused. Problem is the 1 - 2 shift is delayed. It shifts to 2nd at 20 MPH on gentle acceleration, much higher when you get on it of course. The easy throttle shift to 2nd should really be down at 10 to 15 MPH. When it does shift, it shifts fine, no slipping. All the downshifts and engagements seem to be fine. Its just the 1 - 2 shift is delayed. Engine is really starting to rev at 20 in 1st!
I have adjusted the TV Throttle Valve Rod properly, it was close anyway.
I thought it was a classic case of a restricted Governor, that it was taking more output shaft speed to get enough pressure through the Gov to oppose the TV pressure and work the 1-2 shift valve.

So I pulled the extension housing and separated the Gov from the counterweight. It and its screen were clean, no sticking or junk in it. Darn! I did notice that I could move the counterweight a little bit on the shaft. The book said after pulling the snap ring, you may have to tap the Gov counterweight with a mallet to get it off the shaft. Not on this one!
I also changed ATF including the T/C, the old fluid was red, no bad smell, the pan was pretty good inside, no chunks or metal. Changed filter and put it all back together.

No luck, exactly the same. Have since read on a website that the locating ball in the output shaft can wear the counterweight, dropping pressure. Don't know if that is the problem or not. I have heard of this delayed 1 - 2 shift symptom before on AOD's, but don't know what the solution was.

I tried the book's Governor test, which is accel to 25 MPH and back off the gas, should shift up to 3rd, which it does.

Any ideas? Help!

sorry this is so long, but I wanted to get all the info right.

 

Back to the top. Anybody????

 

If you have an adjustable modulator try adjusting or replacing it. If by some chance it is an aod-e the 1-2 solenoid might either be bad or getting a bad signal.

John

 

>I'm running out of ideas.
>'83 AOD behind a 302, with a 3.08 rear end. No previous
>history known, but does not look like abused. Problem is the
>1 - 2 shift is delayed. It shifts to 2nd at 20 MPH on gentle
>acceleration, much higher when you get on it of course. The
>easy throttle shift to 2nd should really be down at 10 to 15
>MPH. When it does shift, it shifts fine, no slipping. All
>the downshifts and engagements seem to be fine. Its just the
>1 - 2 shift is delayed. Engine is really starting to rev at
>20 in 1st!

Well I would say if the engine is starting to realy rev at 20 mph and you have 3.08 gears your transmision is sliping badly. Guess it all depends on what you call rev.

 

No, its not slipping. Minimum throttle 1-2 shift should be at 8-13 MPH, I get 20 MPH. With moderate acceleration should shift at 16-26 MPH, I get 40 at least. WOT should shift at 33-46, I don't want to try it without a tach to watch redline!
The 1-2 shift just happens at too high of speed. But it does move higher in speed along with harder acceleration like it should. Just the whole range is shifted to high in speed.
After it finally does the 1-2 shift, it does the 2-3 right after that, as the 2-3 shift was stacked up waiting on the late 1-2 shift to happen.

I have:
Checked and cleaned the Governor, no luck.
Replaced the Governor, counterweght body and locating ball, no luck.
Put in a new Valve Body, no luck.
Adjusted the TV Rod to have a whole 1/4 inch gap between it and the throttle lever, no luck.
Adjusted it to 1/2 inch gap to say what the hay, does it have any effect at all? No luck, still 20 MPH 1-2 shift at the lowest, but with a 1/2 inch gap it started to slip at the 3-4 shift, so I put it back. So the TV rod IS changing control pressure.

I'm stumped. Dead out of ideas . It would seem that whatever is wrong is up in the case, but what I dunno. When it does shift, it shifts well, so I would think that a clutch piston seal isn't bad, and worn out friction plates would make it slip when shifting, which it doesn't do. The only slip I got was when I backed off the TV rod and dropped the pressure too far.

HEEELLLLLPPPPPPPP!!!

 

What about the vacuum line to the modulator? Is it good? No cracks or leaks, or clogged?

It's the only other thing I could think of.

Roger

 

No vacuum modulator on a AOD. Early AOD's use a rod called the TV rod from throttle to trans. The more the throttle is opened, the more the rod is pushed. It increases the TV pressure in the trans. Later AOD's have a wire cable instead of the rod to do the same function.
Thanks anyway, lanero.

 

Double check filter/filter gasket. And I had a 1982 AOD that I put a shift kit into and I was very pleased with it.Its transtar #k53908 For $25 bucks. Call 1.800.831.0884 and order one.You can program the thing how you want it to shift.

 

Hi Torky, Ken here, I'm afraid you have a 1-2 shift valve problem. Anything from a broken valve body gasket to a twisted spring under the 1-2 shift valve or the valve under the shift valve and spring is sticking. Your best bet is to take the truck to a good trans shop and pay the price. Good luck Ken.