AOD Won't Downshift Easily

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AOD Won't Downshift Easily

June 14, 2006, 07:04:31 AM

I'm not sure if this is a common issue with the AOD trannies but mine doesn't like to downshift unless there is an extreme change in speed. For example, driving at 60 mph I have to slow down for a 45mph car. Increasing speed and going to pass the AOD likes to stay in the high gear unless I mash it and force it to shift. Same thing around town. Once it gets to a cruising gear it like to stay there. I have driven it around town in OD and D with no difference.
The tranny is part of an 88 Cougar LS with a 5.0 and 48K orig miles. It runs great - I'm just trying to get all of the little things right. When I pulled the avg speed driven prior to my purchase it came up to a whopping 26.5 mph!
I checked the TPS voltage and it was 1.06 - I moved it back to .996. It made no difference in the shifting issue but thought I would mention checking it here.

AOD Won't Downshift Easily

Reply #1 – June 14, 2006, 10:33:18 AM

At what speed does the car shift into OD under very light throttle?

AOD Won't Downshift Easily

Reply #2 – June 14, 2006, 10:38:38 AM

On an even, light accelleration it will hit OD at about 44 mph. Driving around town holding a slow and steady 35 it seems to hit OD (in and out). Many times around town I will put in in Drive to avoid the constant in/out of the OD

AOD Won't Downshift Easily

Reply #3 – June 14, 2006, 10:54:52 AM

When the TV (kickdown) cable is properly adjusted, overdrive should kick in at around 45 mph under normal acceleration. Hunting in and out of OD is not good for the transmission, as the OD band is weak to begin with. You'd be better off locking out OD and keeping the car in just D if you are travelling under 45 mph for less than 10 minutes at a stretch. If you'd be going over a steady 45 mph, then OD should be engaged.

You may need a TV cable adjustment. But I would suspect that a fluid/filter change would probably help more.

AOD Won't Downshift Easily

Reply #4 – June 14, 2006, 02:13:21 PM

Quote from: EricCoolCats

When the TV (kickdown) cable is properly adjusted, overdrive should kick in at around 45 mph under normal acceleration. Hunting in and out of OD is not good for the transmission, as the OD band is weak to begin with. You'd be better off locking out OD and keeping the car in just D if you are travelling under 45 mph for less than 10 minutes at a stretch. If you'd be going over a steady 45 mph, then OD should be engaged.

You may need a TV cable adjustment. But I would suspect that a fluid/filter change would probably help more.

Basically what I was going to say...also, not that I recommend this, but a lot of my trans woes went away after the installation of my B&M shift kit...seems like Ford has a problem with heat warping the valvebodies just enough to cause the gasket not to get a good seal...In some cases, I've even separated valvebodies and re-torqued them(by feel, not a torque wrench) and eliminated the common "morning sickness".

AOD Won't Downshift Easily

Reply #5 – June 14, 2006, 07:24:33 PM

Changed the tranny fluid, filter, etc. I ran the codes and it threw a #34 - PFE or EVP circuit above the closed limit of .67 volts. Still don't know how it drives - avoiding making another charge through the mud that the hurrricane brought. I'll know more about the performance in the morning.
So what's my next move, replace the EVP sensor? Should I disconnect the battery and reset everything afterwards?

AOD Won't Downshift Easily

Reply #6 – June 14, 2006, 09:59:25 PM

The EVP may not be the problem though...could be the EGR valve itself...you're probably better off replacing both...I had a similar problem awhile ago and ended up having to replace the EGR vacuum control solenoid as well.

AOD Won't Downshift Easily

Reply #7 – June 14, 2006, 10:24:39 PM

I thought about that. I'll probably just change the EVP and see if it quits throwing codes. If not, I can always get the EGR, too.

AOD Won't Downshift Easily

Reply #8 – June 15, 2006, 09:05:52 AM

The fluid/filter change was a big success! Ran and shifted like new.
Then I got to work and noticed fluid draining from the tranny pan. Fortunately I have a shop 2 blocks from work and they can stop the bleeding. It's all I could do to keep it in gear to get it there. All I can figure is I didn't tighten the rubber gasket that came with the kit correctly. NEVER had that happen before. Never used a rubber gasket either. Had to swallow some pride to bring it to the shop. Even so, I know the ride will be better after the leak is fixed.

AOD Won't Downshift Easily

Reply #9 – June 15, 2006, 10:55:10 AM

the rubber AOD gaskets are complete trash....stick the cork. 1/2 turn past finger tight will usually net you a leak free pan.

AOD Won't Downshift Easily

Reply #10 – June 15, 2006, 12:12:01 PM

Yeah, it was a hard first lesson to learn. I just "assumed" the gasket in the kit was cork. Oh well, the leak is fixed and all is well - I can swap out the gasket when I find a convenient time.