What would you do? auto trans question

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furyus2

furyus2

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OK, I've had problems with my 727 not having kickdown, and the shift points won't change with adjusting the throttle pressure. Yes, the throttle pressure lever is all the way back when the gas pedal is floored. Did the air pressure tests, and the only thing I noticed was the front servo didn't hold air pressure like the rear servo did. Took the trans to a large transmission shop to have it rebuilt. They say there's nothing wrong with the trans. Was told they would try a new valve body. Then they say they don't have one for that particular year. They want me to re install the trans, and if it doesn't work, bring it to them.
questions: Should the front servo hold air pressure with an air test?
I thought other than valving, all valve bodies were the same?
Would you re install this trans without knowing what the issue is?
I'm not young, and I don't have the energy to keep pulling, and installing transmissions. Thanks.
 
I would consider a manual valve body. Then you can shift whenever you want. Makes driving an automatic more fun as well.
 
furyus2 said:
Would you re install this trans without knowing what the issue is?
Click to expand...

Oh yea, and then deal with the no KD.
You can't test a valve body unless it's in the car and running, and just so you know there are servo rings that can be changed easily by the shop if you feel you can't do it.

Also just so you know, lowering the overall pressure in the trans may very well give you kickdown back. (not a lot, maybe 5 lbs and retest)

I have a part throttle kickdown valve assembly sitting here I'm going to end up selling that came out of my 904 because the planetaries went in it so I am swapping to a 42RH OD.
The part throttle kickdown valve assembly is really easy to install also, and it not only brought my kickdown back but kickdown came in somewhat earlier than factory which was nice.
Let me know if you need it, and do some research on it in the meantime.
 
I already have a manual valve body in my 64 Sport Fury. I wanted this car to be a nice driving car I can just get in and go. Also, the car is a column shift. Not very effective for manual shift.
 
TrailBeast said:
Oh yea, and then deal with the no KD.
You can't test a valve body unless it's in the car and running, and just so you know there are servo rings that can be changed easily by the shop if you feel you can't do it.

Also just so you know, lowering the overall pressure in the trans may very well give you kickdown back. (not a lot, maybe 5 lbs and retest)

I have a part throttle kickdown valve assembly sitting here I'm going to end up selling that came out of my 904 because the planetaries went in it so I am swapping to a 42RH OD.
The part throttle kickdown valve assembly is really easy to install also, and it not only brought my kickdown back but kickdown came in somewhat earlier than factory which was nice.
Let me know if you need it, and do some research on it in the meantime.
Click to expand...
The shop I took it to claims they completely disassembled the trans, checked it, and re assembled. I'm guessing they put the servo pistons back in correctly. I want to pull the pan and air check the servos, but I need to know if the servo should hold air when I apply, or should I hear some leaking, even though I still see the band being applied.
and again, the shop told me that I need a one year only valve body. I believe this is false. I know the earlier ones up to 65 are different. What are the facts. From my conversation with the owner, I think he thinks it's my adjustment of the throttle pressure. I don't because when the pedal is floored, the throttle pressure lever is all the way back. Will this high pressure keep the throttle pressure from adjusting at the carb? This is part of my research, but I will need to read up on adjusting the pressure. If I can get my specific questions answered, I can move on to the next thing.
 
furyus2 said:
The shop I took it to claims they completely disassembled the trans, checked it, and re assembled. I'm guessing they put the servo pistons back in correctly. I want to pull the pan and air check the servos, but I need to know if the servo should hold air when I apply, or should I hear some leaking, even though I still see the band being applied.
and again, the shop told me that I need a one year only valve body. I believe this is false. I know the earlier ones up to 65 are different. What are the facts. From my conversation with the owner, I think he thinks it's my adjustment of the throttle pressure. I don't because when the pedal is floored, the throttle pressure lever is all the way back. Will this high pressure keep the throttle pressure from adjusting at the carb? This is part of my research, but I will need to read up on adjusting the pressure. If I can get my specific questions answered, I can move on to the next thing.
Click to expand...

The kickdown can go away just because of a change of the mainline pressure inside the valve body (which by the way can be adjusted inside the pan.
A little bit too high and KD will go away and nothing you do with the TP adjustment will solve it.
Personally I'd try backing the pressure off by turning the pressure regulator adjuster clockwise one 360 degree turn and see what she does.

As far as the servo question, you will hear air as it does get around the rings with an air test. (fluid is thicker remember, so it won't let near as much fluid by as air)
If it applies the band with air it's probably just fine.

As far as I know everything after 65 is the same and basically interchangeable outside of a few drum and shaft changes over the years.
Did they give you specifics as to why they feel it's a one year only trans?

If you have the TP rod adjusted so it goes all the way back at full throttle and don't have KD it's because the mainline pressure is too high, or your trans doesn't have the part throttle KD assembly.
 
Rear servo's use rubber lip seals and front servo's use steel or Teflon rings so air gets by the rings a lot easier that it does the rubber lip seals. (your's sound pretty normal to me)
 
Thanks, that helps a lot. I guess I can go ahead, and install the transmission. I think I would like to have a stock valve body, and get it working properly, then worry about modifying it later. Your answers tell me a lot, but would the pressure adjustment being off keep me from adjusting the shift points?
 
furyus2 said:
Thanks, that helps a lot. I guess I can go ahead, and install the transmission. I think I would like to have a stock valve body, and get it working properly, then worry about modifying it later. Your answers tell me a lot, but would the pressure adjustment being off keep me from adjusting the shift points?
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Yes. The normal shift kit instructions usually say to adjust the regulator spring (the allen wrench one) where you can fit a 5/16 bolt between the plate and cage. Depending on which spring is under the cage this can be too much and be over riding any signal from the kick down. Like the beast said I would back off the regulator a bit and see what happens. This can be done in car.... Needle nose vice grips may be required though....

linepreadjvb01.jpg
 
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time for more spring on the kickdown/throttle valve if the base pressure is too much. Or someone cut the throttle valve to short. Was this a built VB? This shop should be able to fix this for you. Its in the VB, not the trans, so put it in, and take it to them to assess.
 
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