Drivetrain Aod Tech Guys Heeeelp!

95Vert383AOD said:

Wow thanks guys for keeping this alive. I parked my car for the winter so YEAH i still have the issue. Please tell me i can check this "shell" by removing the tail shaft and not the whole transmission again. The transmission builder concluded that the issue must be in the aftermarket valve body. I was going to drop it in spring and have it rebuilt. Before this i used to have an issue where the reverse would kick in and out. and would be more constant if i have the car a little throttle.

Thanks again guys.
Chris

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Sadly, you can't check it by taking the tail housing off. Trans will have to come apart and be tore down

Valve body included? Another possible thing is the computer has what they call shift adapts. It changes pressures to compensate for issues. They need cleared when the trans is repaired or altered. If you didn't have the battery disconnected for long that could cause some issues. OH another thing. The valve body bolt length. You have to be very careful because the size is close and they will hit the band and apply it. It can lock the drum still and make you slip the clutches to overcome it. I dunno. I would say put a pressure gauge on it and check the pressures in all ranges.

95Vert383AOD said:

Its an AOD. No electronic shifting. The car has a manual computer.

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Read the rest of his post before ya blow me out. We were talking about a 4l60e.

All good, I was busting your chops.

gearheadboy said:

Valve body included? Another possible thing is the computer has what they call shift adapts. It changes pressures to compensate for issues. They need cleared when the trans is repaired or altered. If you didn't have the battery disconnected for long that could cause some issues. OH another thing. The valve body bolt length. You have to be very careful because the size is close and they will hit the band and apply it. It can lock the drum still and make you slip the clutches to overcome it. I dunno. I would say put a pressure gauge on it and check the pressures in all ranges.

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We did hook a gauge to the troublesome transmissions. They would always read way low. Even with new pumps, new valve bodies, and with the vacuum modulator conversion kit. I can't recall the numbers since it's been a while, though. And I always disconnect the battery before I work on them (unless they're the open bellhousing ones) and don't connect it back up until trans is rebuilt and back in the vehicle.

Here's some more info. We had one do this to us and my dad (he's actually the builder, I'm just the R&R guy usually) put 2 valve body gaskets on each side of the plate (he's figuring that the case is slightly warped causing loss of pressure somewhere). The slight initial slip went away and it drove and shifted excellent. We thought we had the issue fixed, so we let it go and then about two weeks later the guy calls us up and says he has no reverse. I'm thinking to myself "Ok this idiot broke the sun shell" but no. We get it and I pull it out and dad tears into it. Pretty much completely burned up again. So it's some sort of internal leak I'm figuring. Because it's not a faulty internal part or else JUST swapping the case wouldn't fix the issue. And I can't see it being something my dad is doing wrong, he's been building for over 30 years
and I know people do make mistakes, but these transmissions are basically our bread and butter so to say. If there were no '93 to like '05 GM trucks in my area, we'd honestly be outta business.

Don't know what to say. Yes if the pressure is low you probably have an internal leak which will burn everything up. I am really funny about valve body and spacer plate gaskets being OEM and you have to match them things up carefully. One different passage not open or closed will ruin you.

89BlackGTvert said:

You have a lockup convertor. I have one also with a lentech VB. If I don't quickly ratchet past 3rd, my car will stall. That's because when you have a AOD and lockup it does it automatically when you hit 3rd. I am thinking about going non-lockup myself.
Sent from my PI86100 using Board Express

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I have a 93 gt with lentech v/b and edge racing non lock up and that's the way to go