78anniversary

Hey guys, I did a 200-4R conversion a couple years ago in my 78. The trans has less than 3000 miles since the rebuild. Used the BTO conversion parts and it has worked great up until now. Yesterday it started to shift at the wrong time, very delayed, at too hi of an RPM, and most of the time it wouldn't even shift past 3rd gear. Nothing has changed, fluid level is good and fluid looks clean. The TV cable hasn't moved from where it has been set since the beginning.

Has anyone got any thoughts on this?

'75

As a guess, I will suggest a governor sticking issue or maybe the throttle valve stuck. You could try sending a message to fourm member Jake's Performance , He is a 200-4r expert.

78anniversary

Thanks, I will give him a try.

78anniversary

anyone else?

682XLR8

Check your fluid pressure as per BTO's instructions. Also try adjusting the TV cable if you haven't done so already

78anniversary

Good idea on the pressures...you wouldn't happen to have them would you? not sure if i can find mine.

682XLR8

Here's what I have written down when I did my BTO conversion:


Pressure @ idle Pressure @ high idle(in gear, foot on the brake)
Park 75-80 180-210
Reverse 120 270
Neutral 75-80 180-210
Fourth 75-80 200-210
Third 75-80 200-210
Second 210 210
First 210 200-210


These pressures were taken the day I got the car on the road after installing the trans. A few years later, I ran another pressure check, and found the numbers for first and second down slightly(can't recall how much, I should have wrote it down), but everything works fine so I don't think lower numbers from what I have posted would be a problem. If the numbers are a lot lower, then you should consult a trans expert as posted earlier.
I'm wondering if a clogged filter would cause the problems you're having....when's the last time it was changed?

78anniversary

Thanks for the info, I will check them out. As per the filter, it hasn't been changed yet being the trans has got less than 3000 miles.

Red 69

682XRB, I have a 2004R rebuild core for a future project and have one question on the pressure set up. Would you say setting the ATV cable fully extended on WOT would yield pressures in the desired range? Is the ATV cable on your car fully extended on WOT? I'm just curious, as this is the way I have set up other transmissions successfully without any pressure check. Thanks for sharing the info!

682XLR8

The pressure check was necessary for the warranty. I had to take measurements according to BTO's instructions and call them in to make sure they're in tune with the readings BTO wrote down when the first built the trans. Then the warranty kicks in
About the TV cable, I can't tell if it's fully extended(goes out a ways though) I would say as long as you're adjusting it the way GM says to do it, you should be fine

Ganey

The cable needs to be carefully checked.
I had a 2004R in a SS & saved this pressure check info.:

http://forums.corvetteforum.com/1560819997-post2.html