AOD Question

fturner

Registered User
Hey folks,

Earlier this year I installed a tranny cooler on the car, and I had noticed that the transmission was more consistent on how it changed through the gears. The shifts stayed firm etc without getting that lagging feeling you would get on a really hot day. Now this AOD as far as I know is the original but has been VERY well taken care of with fluid and filter changes on a regular bases. There is no slippage that I am aware of.

Now I'm getting concerned. Since I've upgraded the blower and obviously making a couple more ponies, I'm finding the shifts up still consistent (mind you, they are harder) even at WOT which is fine. What is scaring me is how hard it SLAMS!!!! down into a lower gear when I nail it while cruising. For example, this morning I nailed it to pass someone, and it came out of OD into 3rd.... and I thought something was going to get busted with how hard it hit 3rd, and I mean SLAMMED into 3rd. I have never felt that in this car or any other , even sticks.

I don't want to live by the old saying of "Something is going to move, lets just hope its the whole vehicle" (of course in reference to the old jets that used water injection :D).

Can the old AOD handle that or should I shift manually down before going for the gusto now, or should I start looking at upgrading?
 
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I did do a search, for 3 days actually and saw more posts about doing a search than getting answers :rolleyes:.

The TV pressure has been double checked and all that is good. The transmission acts perfectly up shifting and down shifting etc. The concern is when it downshifts when I slam the gas, and how hards it slams down.
 
Who did you get the transmission from? When I had the Art Carr AOD with their valve body, I always thought the downshift was too harsh.
 
It sounds like the line pressure is increasing for the up shift, but not bleeding off for the down shift. Maybe have the line pressure checked :confused:
 
Maybe it would help to get some other club member to ride in your car and see what they think. Maybe they are used to shifts that harsh. It's really hard to judge since you're the only one with first-hand experience of it.
 
The transmission is the original stock AOD.

If it hasn't broke, something is going to break I think :eek:.

Normal driving and everything is like it was before with upshifting and down shifting, smooth no slams. As I mentioned though, since the cooler went in, the shifts stay firm like the car was when she was cold.

I did read somewhere that some coolers can cause enough back pressure to affect line pressure, but wouldn't that show up all the time through shifting up and down?

Today I decided to shift manually to 3rd then I nailed it after it shifted, and I didn't get that slam.... it smoothly shifted into 3rd. For now I'm just going to keep doing that.
 
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I wouldn't think the cooler lines would cause enough of a restriction to make a downshift so harsh. Since its only the 4-3 shift that has the problem, sounds like could be related to one or more valves. Broken spring, debris holding something open.. There is valve known as 3-4 backout which relates to the 3-4 shift and possibly 4-3?

If you're adventurous, you can pull the valve body out and inspect it for broken springs or debris. IMO, it doesn't sound like one of the clutches or you'd have some other problem during an upshift. Valve bodys are easy.. don't let them scare you. Just be sure to take a few pictures before you pull it apart and during so that you don't get anything mixed up. A broken spring will be obvious. Clogged valves will not be so easy to notice.
 
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I was planning to change the fluid soon anyway as it is time. Anything I can do to the valvebody while its out that can help the tranny?

I know Ford now recommends Mercon V for these trannies because they are not suppose to use the Mercon III.... Whats people's thoughts on that?
 
I'm not sure ,but, I thought merc v was for the 4r70w trans.I could be wrong.Iknow Art Carr recommends type f after their parts are installed.
 
John Deere Hydraulic fluid is what some people use. I am thinking I am going to swap out trannies soon and am going to use this. Do a search for that and see what you get.

Chris
 
I was planning to change the fluid soon anyway as it is time. Anything I can do to the valvebody while its out that can help the tranny?
In the members drivetrain forum, I've discussed a few of the fine points of the AOD. :rolleyes: At the bottom, there are some tips on rebuilding the valve body.
 
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