4R70W Won't Upshift

Hi,

I hope somebody here can help me with this.

I have a 1994 Mercury Cougar 4.6 V8 with the 4R70W and 160,000 miles. The transmission is original and has not been rebuilt.

Yesterday I backed out of a parking spot, stopped, put the car in 'D' and drove off. I heard the engine revving really high and when I looked it was around 3,0000 rpms. I stopped in a parking lot, cycled through the transmission selections several times and drove off. It didn't fix it. So as it stands my car does the following:

* I have only one 'D' gear. In that gear 45mph is about 2600 rpms and 50 mph is about 2900 rpms.

* If I am driving in 'D' and at 45 mph and I shift into '2' or '1' nothing changes. The RPMs don't change and neither does the speed.

* If I press the 'O/D off' button while driving nothing changes. The RPMs don't change and neither does the speed.

* I can still put the car into park, reverse and neutral with no noticeable problems or differences.

I checked the fluid today after she sat overnight and it was at the right levels. It appeared to be the right color and I did not notice any specs of debris in the fluid.

Before this the only problem that I had started about 7 months ago and it was that I would put the car in drive and I would have to rev her up a bit before she'd move. It only happened when she was cold and I had heard about the fluid pressures in the AOD-Es being finicky so I thought nothing of it. I would back out of a spot when she was cold, put her into drive and apply a little throttle and wait a few seconds and then its like the transmission would 'take' and she'd begin to move.
Also for the last two weeks or so I couldn't start my car when it was parked. I'd turn the key and nothing. I would then shift from 'P' to 'N' and back up to 'P' and then I could start my car. Today I had that problem and just to see I started her in 'N.' I turned her off, placed her in 'P' and she started up again.

I have done some checking and think it can be one of four things: EPC Solenoid, Throttle Valve adjustment, Shift linkage adjustment or unfortunately Overdrive band has died.

What do you think it could be? Am I missing something here? I'm really hoping it isn't a costly rebuild I need.

I appreciate any help you can give me.

Thanks,

Adrian

Hi,

I don't know if this makes a difference but I just wanted to add that at no time with this car has the transmission ever slipped.

Thanks,

Adrian

Hi,

I just wanted to give an update incase anyone has the same problem. I replaced the neutral start safety switch and the up-shifting problems and the car not starting in P or N all went away. I did it about a week and 1/2 ago and have had no problems since. I thought it was weirdest that this wouldn't let the car upshift when driving but who knows the problems electronics can bring.

Thanks,

Adrian

That's the MLPS and they fail all the time or when installing a trans they are not properly aligned. They tell the EEC/PCM what gear is selected. If it is off then it will not allow the shifts to happen or it will but you will be dropping in and out of gears. Glad you got it figured out though.

our windstar stuck in low gear- was just a bad switch too...the schematics show its just a rotary switch with a resistor array that changes resistance as you move the lever...luckily it was under warranty and a quickfix

on the not wanting to go when cold: my old windstar does it, has for a couple years if it sits more than a week, or 65 galaxie(original tranny!) does it every time I get it out- but it sits weeks at a time tooo...its just the pump taking time to prime up- can indicate filter almost plugged too...ours both have new filters recently, still do it- rather than let the clutches slip till pressure builds up, I just rock the lever from drive-reverse-repeat several times, and it will always engage normally after a few shots to get the oil moving/filling the pump/filter/valvebody or whatever the case may be...might be a worry wart, but I'm pretty certain it will be easier on the tranny to pump oil thru it this way instead of revving/slipping till pressure fills everything up