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Kenny Z.
Kenny Z., Ford Senior Master Tech
Category: Ford
Satisfied Customers: 5355
Experience:  Auto Trans, Drivability and Electrical Specialist
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Ford AOD transmission problems

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About a year ago, I had a transmission shop rebuild an AOD transmission out of an 83 Econoline E150 with a 302. I'm making a hot rod and now just got the unit running. After I got the detent pressue set to 35 lbs. in neutral, I put it through the gears. All forward gears, reverse gear and neutral all had a forward engagement at about 2800-3000 RPM. It was very slow. Also, when moving through the gears a buzzing noise could be heard. Neutral and park had no buzzing noise. While setting the detent, the pressure would range from 0 to 70 plus lbs. Is this problem in the value body or somewhere else. I can't find anyone in my area to answer my question properly. Any help you can give me will be appreciated.

HiCustomer Thank you for asking your question on JustAnswer.


Did you use the guage block while setting the pressure?


What is the tv pressure at idle with out the block installed?


Do you have the means to check line pressure also?

Customer: replied 8 years ago.

I have no gauge block....I just used a gauge


I adjusted the tv pressure by the description in the manual by setting

It at 35 lbs. at idle.


No, I don't have the means to check the pressure line.


Why do I have forward movement in reverse and neutral positions

as well as in the forward selection position?

I was getting to that, just wanted to be sure you had the tv set correctly. A guage block must be installed when setting the tv to 35 psi.With the block out tv should be near zero at idle. I don't think the tv is your engagement problem.If the trans has been sitting a year and never used then something was probably assembled wrong during the rebuild.The valve body can't apply forward and reverse at the same time unless the wrong sep plate gaskets were used.Without seeing the trans disassembled it is hard for me to say,If you have to rev it to 2800 to get it to engage and then it engages fwd and rev at the same time there is definitely something besides tv pressure causing it.forward or rev clutch stacked to tight,one way clutches installed backwards,stator support seal rings mis installed,broken or missing......I would try to set the tv correctly then reevaluate...Sounds like you have the tv too high if you set it to 35 on the hard stop then its actually more like 70.That is probably causing the whining/buzzing the pump is at full line pressure especially if you are in the throttle then tv is closer to 100.This could cause crossbleed on the stator support seals,line pressure would be 300 psi plus at that point.






This revised method of setting TV linkage on all AOD transmissions is the only way to adjust the linkage to the middle of the specification curve. This method sets the linkage to the most sensitive point.

The new procedure attached uses a TV control pressure gage block service tool D84P-70332-A. If that tool is not available, alternates are listed in the procedure. Highlights of the new procedure include setting the TV linkage at idle with the gage block installed to 35 +/- 5 Psi.

The "TV pressure method for adjusting the TV linkage" procedure is recommended for transmission shift concerns while the "Linkage Adjusted at the Carburetor" procedure is recommended when the idle speed is changed by 50 RPM.


The following procedure may be used to check and/or adjust the throttle valve (TV) rod linkage using the TV control pressure.

1.Check/adjust the engine curb idle speed to specification required.
2.Attach a 0-100 PSI pressure gage, T73L-6600-A, with the adapter fitting D80L-77001-A, or equivalent to the TV port on the transmission with sufficient flexible hose to make gage accessible while operating the engine.




Obtain a TV control pressure gage block, service tool no. D84P-70332-A, or fabricate a block .397 +/- .007 inch thick (Figure 8). The following drill bit
shanks may also be used in order of preference:Letter X (.397 inch), 10 mm (.3937 inch) or 25/64 (.3906 inch).
4.Operate the engine until normal operating temperature is reached and the throttle lever is off fast idle or the Idle Speed Control plunger* (if equipped) is at its normal idle position. The transmission fluid temperature should be approximately 100-150~ F. Do not make pressure check if transmission fluid is cold or too hot to touch.
5.Set parking brake, place shift selector in N (neutral), remove air cleaner, shut off air conditioner. If equipped with a Vacuum Operated Throttle Modulator, disconnect and plug the vacuum line to this unit. If equipped with a Throttle Solenoid Positioner or an Idle Speed Control,* do not disconnect either of these units.


IMPORTANT:Do not make pressure check in Park.


6.With engine idling in neutral, and no accessory load on engine, insert gage block (or drill shank) between the carburetor throttle lever and adjustment screw on the TV linkage lever at the carburetor (Figure 8). The TV pressure should be 35 PSI +/- 5 PSI. For best transmission function, use the adjusting screw to set the pressure as close as possible to 35 PSI. Turning the screw in will raise the pressure 1.5 PSI per turn. Backing out the screw will lower the pressure. If equipped with Idle Speed Control, some *"hunting" may occur and an average pressure reading will have to be determined. If the adjusting screw does not have enough adjustment range to bring TV pressure within specification, first adjust rod at the transmission as described in the Shop Manual.
7.Remove gage block, allowing TV lever to return to idle. With engine still idling in neutral, TV pressure must be at or near zero (less than 5 PSI). If not, back out adjusting screw until TV pressure is less than 5 PSI. Re-install gage block and check that TV pressure is still 35 PSI +/- 5 PSI.


*NOTE: Idle Speed Control is only on 1984 3.8L engine with AOD transmission.



Customer: replied 8 years ago.

Thank you for your reply. Unless I purchase a gauge block, I

do not have access to one. I will look at your alternative suggestion.

What is your opinion of installing a shift kit in the stock valve body?

What about purchasing TCI's constant pressure valve body? Would

these help?

There were alternatives in the procedure for guage blocks.You can fabricate one using the measurements provided or by using the size drill bit that was referenced in the procedure.

I think a mild / moderate shift kit would be ok, but if they did not beef up the trans at all during the overhaul then I would not increase pressures too much because the factory parts will not handle the increased pressures.If you do get a kit a would recommend one from baumann.They are the best and all I use.The kit lets you decide how much firmness to add to the shifts and effectively addresses the O/D servo pressure apply that plagued these transmissions for years. I do not think a kit will help your current problem. I would get the TV pressure under control and if that fixes all of your concerns then think about the shift kit.


Baumanns site

Customer: replied 8 years ago.

If I understand you right, you do not recommend increasing the pressure

on the rebuilt transmission by putting in a shift kit. Are you familiar at all

with TCI's Constant Pressure Valve Body. By the description, all you have

to be concerned about is setting the tv pressure and you are good to go. Maybe

Baumann has somewhat the same thing. Thanks, Kenny

Thats not what I said actually, Its ok just not the axle snapping kit if you want the trans to hold up, and waiting until you have the trans shifting/engaging correctly before installing it.
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