no 3rd or 4th gear
 

On the way home tonight, the 83 downshifted from 4 to 3. Strange... A mile or so later, back to 4, then it would not pull in 4 and shifted it to 3. About 20 min. later, and about 15 miles, 3rd stops working. The only thing I have now is 1,2. On a dark windy road.

What am I in for? using the search,I have read about cleaning some screens in the valve body, to full trans rebuild.

this is the car that has had a fluid leak, the rad. leaked water into it, and it has been ran low to the point of not moving the car.

It has ran great since fixing the rad. and the trans dipstick o-ring. then this tonight.

If I power brake the car, the trans holds firm, and will even spin the tire in the gravel. But dead in 3,4. If the car idles for a minute, I get maybe 100yards before 3-4 are gone again.

Help

Definetly a STEVEBFL question
 

He should be at his shop and checking the forum by about 8 AM EST.
MONDAY

I assume you have the correct fluid level?

It sounds to me like a valve body problem or a servo on one of the bands misbehaving. If you hold your mouth right, you may be able to fix this without pulling it. How many miles are on it?

From the ATSG manual

1. Check regulating pressure, if no regulating pressure is indicated, continue with item 2. If regulator is in order, perform item 3.
2. Clean centrifugal governor and make operable.
3. Disassemble, clean shift valve housing and exchange if required.

When mine did this, it was because of excessive internal leakage from a worn out trans. If the trans has got over 200k on it, it really needs rebuilt.
I have had 3 of these apart so far between 215k and 230k. 1 of them had worn out B3 and K1 clutches, 1 had just the B3 worn out and the other(my 300sd) had all 3 clutches worn out along with a busted planetary gearset.

Where are you in washington. If yours does need rebuilt, I would do it for half of what a shop will charge.

I have the correct fluid level, and dextron fluid.
I do not know how many miles are on it. I got the car with a broken odometer at 299K. Put in the odo from another car, and have logged close to 15K on my own.

It has not been slipping at all prior to this.

Found this http://www.peachparts.com/shopforum/tech-help/201899-try-repair-when-your-xmission-wont-shift.html About clogged screens?
Fluid does not smell burnt, and is a nice red color

Did anyone mention switch under fuel pedal,could be hung up?

With 300k+ on it most likely has been rebuilt previously, very few make it that long without being rebuilt.

Definitely worth a try on the screens. Done it before myself its pretty easy.

Let me know if you need a hand.

thanks BG, Hope it does not come to pulling the trans.
One more bit of info. When bringing this home yesterday, I got it into 3rd a coupe of times, and it pulled really well, until it downshifted again.
How do I disable the kickdown switch under the pedal, Could the bowden cable be stuck? seems to move ok at the engine side. how would I check that.
Thanks

Just unplug the switch under the pedal, or disconnect the kickdown at the trans. Passenger side, just in front of the mount. Single wire.

I pulled the pan.
there is nothing there but fluid. I did find a small rock, from when the dipstick had all of the issues.
The bowden cable is actuating the plunger, I will refill it in the next day or so, and unhook the kick down switch.
Would it be worth running transX or seafoam in this when I refill it?
Any other ideas.
the fact that there was no metal, or build up at all is good news, right?

A lot of the junk gets trapped on top of the valve body plate. But it is good that theres not much in the pan. You should really check out those screens before you put the fluid back in it. Its really pretty simple to do. If you are carefull you can do it without changing the gasket.

Did you unplug the kickdown switch yet. It would be nice if it was something simple. :o

I have not done the switch yet. Anyone know what the voltage is spposed to be at the trans? I would like to check it with a meter first.
And what about the vacuum modulator? Those are the 3 things that can make it down shift externally correct?