Hey guys, haven't been on this forum for ages but lookin for some help from the fox body guys that know about AOD Transmissions. I originally posted this question in 2021 and just put the car aside out of frustration and worked on my F100, Now I'm trying to get back on the Mustang. I put an AOD out of an... 87-ish Mustang into my '68 coupe and after topping off the fluid, adjusting the TV cable, checking for leaks etc, took it out for its first drive. It moved forward and back in the garage and I was stoked but on the test drive, the transmission refused to shift out of first gear. Revving high in first it just seems to want to hold in gear. When you let off the gas the hydraulic pressure is released as if it shifts, it doesn't engine brake like it stays in first. Then when you attempt to accelerate again, it's like its not in gear at all, the transmission just free revs. At this point it is out of first but not in second. Could be in high gear i suppose. If I put the trans in neutral, then back into drive, I have hydraulic pressure again and the trans grabs again but is again in first gear. The AOD has a B&M shift kit and Hughes 2500 stall converter, other than that, stock.

Could this be a symptom of a bad lip seal on the piston between the forward clutch and forward drum? I fought and fought that seal and was never convinced it was perfect. it's of course a total rebuild to replace that so trying to narrow down what to look for.

looking at the transpartsonline diagram, it is item 334 and 335 https://www.transpartsonline.com/TRA...sPartsType=AOD

 

Although i have never seen anything about it, I have witnessed people back flush a ford AOD by jacking the rear end, throwing them in reverse and stomping the gas. This is needed when the trans gets turned up its side during an install.

I assume you drove the mustang the transmission came out of before pulling it?

 

After thinking about it, back flushing may actually work.

 

not sure I understand the idea... like to remove air in the hydraulic system? or just get fresh fluid throughout?

Doing some research, it pointed me away from the lip seal on the forward clutch and back at the throttle valve and/or valve body in general. I hooked up a pressure gauge to the TV port and got the car running. With the car approaching operating temp and idling in neutral the TV pressure was upwards of 60 psi. I loosened the TV cable to make sure it wasn't too tight, with tons of slack, still over 60 psi. Let the car cool and looked at throttle valve assembly, it does not seem to be binding or stuck open. does that align with the backflush idea or...
I suppose my next move is to pull the pan and take a closer look at the valve body...

 

sorry it didn't work for you Let us know how it turns out

 

All this guy did was change his fluid and filter and it did what yours is doing.


Transmission fluid is a detergent. If the fluid goes long enough without being changed, that detergent doesn't clean anymore and crud starts to accumulate. When the fluid is changed, new detergent is being added, thus breaking up that crud build-up and accumulating it in veins of the torque converter. This is why dealerships flush, instead of just change filters.

 

Didn't say it didn't work, I evidently don't understand what you are saying to do... jack up the rear end and gas it? what...what would that accomplish?
Some explanation and logic might help here, a video of a guy with similar transmission problems doesn't clear it up. This is a freshly built transmission so crud buildup should not be an issue.

 

If your problems are with TV and cables I have worked in the industry for over 10 years, maybe I can help... if i understood your problem. TrimpDrippers thinks you should try something that you haven't... and wouldn't be difficult. I'd say ignore his advice, and buy new stuff.

 

It may be too late for that. It only takes a couple of miles of driving to burn an AOD up if that cable is left unhooked. As soon as it hits OD, you can pretty much kiss that thing goodbye.

 

Another thing I didn't think about; is even though the transmission is new, that doesn't mean the cooler didn't have a bunch of crud in it. Probably when you fired it up, you flushed all kinds of trash through the system.

Edit: There are some service bulletins for the AOD on the line. One of them includes adding an inline filter. You are smart, so i will let you look those up.