727 3rd gear feels more like a down shift

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dgibby

dgibby

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Started today. When I shifted into 3rd if either was very slow to engage or almost felt like a down shift. When cruising slow speed it actually slowed the car down and didn't want to accelerate. Any ideas?
Rebuilt 5k miles ago. Clutches, bands, seals, bushings, sprag, servos, all new. Fluid is fresh and not burned. Thanks for the help.
 
New reverse valve body was also installed with rebuild.
 
Manual vb. No linkage.
Not sure if it makes a difference but first gear is solid, no slipping and second seems fine too
 
I only have experience with manual vbs that were factory vbs converted to manual through the use of a shift kit. They DEFINITELY still require the use of a kickdown, or at a minimum tying the linkage back on the transmission to ensure adequate line pressure and therefore holding power of the bands and clutches.

I have heard but cannot confirm that some aftermarket vbs do not require any linkage.

Without a kd linkage your trans would work but the shift points, when in D, would be very early......untill thd fwd clutch wears out from slipping. When this happens the powerflow in third is the same as first as the fwd clutch slips in third.

The precursor and warning sign of this happening is when the 2 to 3 shift starts to allow the rpm to flare during the shift.
 
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It is a professional built vb. There is way for it to shift automatically. No early shift unless I shift it.
 
Ok. You should then be talking to the professional that "built" the vb. If they used a transgo kit to do it it still needs the kd linkage. Just my 2 cents.
 
Thanks for your input. I'll talk to these guys that "built" my valve body http://coperacingtrans.com/
(Pretty sure it's not a transgo kit)
And maybe someone with "actual" experience with manual vb will chime in with some suggestions also.
Just my 2 cents...
 
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Sorry if I offended you. Just trying to share some knowledge and experience. Take it or leave it, it is up to you.

Sounds like a call to Cope should be the first thing you do. Your symptoms do sound like a forward clutch failure.

Good luck, Iet us all know how you make out so that we can learn!
 
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What does the tach do Dave? Does rpm increase when you shift into 3rd? If so it sounds like the front clutch is slipping for some reason. If the rpm's don't increase my guess is for some reason the front band isn't releasing all the way.
 
Seems like no slippage. Didn't really try to see if it would go because didn't want to risk burning it up. It really seemed more like a down shift, slowed the car down and was very sluggish trying to accelerate but didn't try too hard to get going because of risk of damage. Would go back to second and to third again any it would be fine.
 
You have too much overlap between the 2-3 shift. One possible cause is the 2nd gear band is either adjusted too tight or not releasing fast enough.
 
Well, I adjusted the band 2 1/4 turns and made sure the fluid level was good and it made no difference.
Higher speeds it goes into 3 pretty firm for the most part and at cruise speeds it goes right in but could have several seconds of lag time before it engages.
At very low speeds it has the same lag time and will bring the car to a stop when it does engage.
 
It almost sounds like something is clogging or restricting a passage. Does the fluid have a burnt of off smell? It might be worthwhile to check the filter.
 
belmateo said:
It almost sounds like something is clogging or restricting a passage. Does the fluid have a burnt of off smell? It might be worthwhile to check the filter.
Click to expand...
No, not burnt, fluid smells good and is fresh. I'll drop the pan and see whats going on.
 
I know it's hard to say but if it is going into 3rd is it safe to drive?
My buddy has a shop but it's an hour away but would be nice to get on a lift rather than on my back on the garage floor.
 
dgibby said:
It is a professional built vb. There is way for it to shift automatically. No early shift unless I shift it.
Click to expand...

Do you mean there is NO way for it to shift automatically? It is a full manual reverse pattern valve body?
 
dgibby said:
Yes, full manual reverse valve body.
Click to expand...

Was it made into a full manual reverse valve body with a kit? Or was it bought from someone (like cheetah) like that?

Like someone else mentioned. The kits to turn a stock VB in a full manual reverse still sometimes need the line pressure. If it was bought as a "new" VB from cheetah. Then you probably don't.
 
I agree with belmateo, too much shift overlap.
This could be a VB issue but I doubt it.
Here's the thing; the same oil circuit that energizes the hi-drum for third gear is also the one to depressurize the second gear band. It is supposed to happen simultaneously.
If you had said second gear was sluggish, I would have said that the hi-drum is likely piled up. But since you didn't, and since reverse is fine (which also uses the hi-drum; I have to think that the band is not releasing, or rather that the servo is not retracting.I know of no way for this to occur
But it doesn't really matter. In MO the tranny has to come down.
I don't see a hydraulic pressure test for this.
But you might be able to check the servo by taking off the VB. And you might get to see the servo in action with doing an air-pressure test.
So, then, I recommend an air-pressure test.
 
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AJ/FormS said:
I agree with belmateo, too much shift overlap.
This could be a VB issue but I doubt it.
Here's the thing; the same oil circuit that energizes the hi-drum for third gear is also the one to depressurize the second gear band. It is supposed to happen simultaneously.
If you had said second gear was sluggish, I would have said that the hi-drum is likely piled up. But since you didn't, and since reverse is fine (which also uses the hi-drum; I have to think that the band is not releasing, or rather that the servo is not retracting.I know of no way for this to occur
But it doesn't really matter. In MO the tranny has to come down.
I don't see a hydraulic pressure test for this.
But you might be able to check the servo by taking off the VB. And you might get to see the servo in action with doing an air-pressure test.
So, then, I recommend an air-pressure test.
Click to expand...
Of course I have no idea but it feels like the band isn't releasing since it will actually slows the car down at low speeds, but again, really have no idea.
If I do the servo air test what am I looking for? If it is leaking won't the trans still have to come out to get the kick down lever of to remove the servo or if it passes am I looking at the vb?
 
If you take out the VB and back off the front band adjustment all the way the strut connecting the lever to the band will drop out and let the lever swing out of the way of the servo.
 
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