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I have a 90 TA with a 94 LT1 stock as a rock and a 700R4 with the following mods:

Sunbeast shift kit
.500 boost valve
Correct Throttle Body and TV cable
TV cable adjusted properly
B&M Coverter 2600 stall
Corvette Servo
Kevlar bands
18 months old from an extremely reputable builder
Correct Fluid type and amount

Heres the problem:

It will not downshift whatsover if you give it throttle
It will not upshift until 3600 RPMS
You could be at 20 in second gear and floor it and it WILL NOT downshift.
If you shift manually its fine.
It does not slip, grind, or make any abnormal noises.
Dropped the pan and fluid is clean and no metal shavings at all on the magnet.

This problem has me so confused and frustrated that I don't know what to do.
Any help is GREATLY appreciated.

 

First thing that comes to mind is, although the TV cable is properly adjusted the TV itself is in a bind. How did it look when the pan was off?

Did you have your builder look at it yet?

How long has this been going on?

Did it begin immediately or deteriorate over time?

g

 

We provided the TV cable is working and ajusted properly , I would bet the THROTTLE VALVE is stuck in some mid throttle position. Thats where I would be looking its a very common thing and as long as no trash easy to fix but you will have to remove the valve body.
If you need a diagram for it let me know and ill send it to you.

 

To the first poster: Everything looked great and I put 2 different TV cables on it and with the same result. It happened all of the sudden and never got better or worse.

Performabuilt: Please tell me how to do that? If that would cause something like this problem..is it expensive? Please send me that so I can check it out!!!

 

Will send in the AM and its comon little scratches or burs on the valve or valve body

 

Sounds like the throttle valve is stuck. You can look at them wrong and make them stick!

 

Lol Thats right... if the unit was installed / replaced recently it might be a good idea to go back and flush the cooler again as debris may be caught in the bends of the tubes and is washing out a little bit at a time...

Those dang throttle valves can be very fickle... just hold your breath while yer in there, don't blink and genuflect when yer finished!

Good Luck wid it!

g

 

Thanks a lot guys for all your advice, performabuilt sent me the diagram and I am going to attack it tomorrow!

 

Your welcome on the diagram and if you need anything when working on it tomorrow just give me a call i will be around as ussual all day

 

Awesome, thanks a ton.

 

Ok so update:

The upshift late problem is still there. It will NOT go into 3rd or 4th gear. Otherwise the trans functions flawlessly.

WTFFFF????

 

Do you still have all of the original brackets for the throttle cable an the TV cable from your original set up being used? I can't remember but in 94 they used the 60e and the brackets were different if I remember correctly. Might be something to address. Vince

 

What did you do while you were inside the transmission?

g

 

I didn't go inside of it yet. Waiting for access to a lift from work.

The TB and cable is from a 93 LT1.

 

How does it shift if you try to do so manually?

What happens at the 3rd gear shift... does 2nd continue to pull regardless of rpm or vehicle speed and just does not seem to initiate a 3rd gear shift......or does it release 2nd and engine freewheels?

g

 

Shifts the same manually and 2nd disengages and engine freewheels like you were in Neutral.

 

So it shifts 1-2 but then instead of shifting to third its like neutral ? Thats not the way you described it in the begining post so made things a bit confusing. To me it sounds like you have lost the 3-4 clutch if that the case and are going to need a unit or a rebuild , Sorry to be the bearer of bad news

 

Yeah unfortunately it does sound like you lost the 3/4 clutches, maybe not though. I suspected that after re-reading this entire thread this morning.

Sometimes it is time consuming and hard to diagnose conditions and symptoms over the internet. That is why I ask the questions I do rather than jumping to conclusions.

What strikes me about this unit is you said your fluid is in good shape, that is not typical of a clutch failure... what else can you tell us about this unit? Has it been serviced recently, was there a repair on the unit earlier this year. Usually when a clutch pack fails the fluid will become contaminated. If the fluid has not been changed and it is not in any way discolored or burnt smelling.... I would suggest you have a professional look at it. It is possible that is is losing pressure internally and is simply not feeding the apply circuits for the 3/4 clutches. I have seen stranger things.

Good Luck.

g

 

These symptoms point to a fluid control issue.... that's why the Throttle Valve came in to question.

Today I read this... and it is the first key to the problem!

And this comment speaks directly to a 3rd gear apply problem or a 3/4 clutch failure and is the second key!

This is the important information in this thread that will allow yopu to get to the bottom of the issue. Again, have a pro look at it!

g

 

I didn't put it into the first post because it JUST happened.

The fluid is still cherry red and not burned or contaminated.