Billy1987

iTrader: (10)

Just done the swap on my 99 camaro. The trans does great but when it goes into overdrive it like it is in neutral. Trans was rebuilt but none of the solenoids were changed. Reverse 1st,2nd and 3rd are fine and it locks the converter in 3rd.Any idea what my problem could be? Any help is appreciated.

Vince B

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AFL valve or 1-2 shift valve circuit would be the first place I would look. I'm going to doubt that its an issue with a solenoid because of the fact you have 1st and 3rd gears. I guess its possible that the 4th clutch housing bolt could have been left loose. HTH Vince

Billy1987

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The transmission is a 1991 if that matters any.

Jake's Performance

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It's not in the 1-2 shift valve circuit.
If there was an issue here it would either not shift to first, or it would not go to 2nd. Stuck shift valve, plugged or faulty solenoid. Its none of those because it shifts and the fact it has first means the A solenoid is functioning. 3rd is not related to the A solenoid.

It's likely a mechanical issue and not hydraulic.
The symptoms prove you have all the shift solenoids and valves functioning.

Jake's Performance

iTrader: (2)

Actually it does. 91 and 92 models have different hydraulics than a 93-up. It could be an issue where the A solenoid coming on forces it back to first instead of allowing an upshift, it would feel like neutral.

Vince B

iTrader: (1)

IMO if you have an issue in the AFL circuit bore you see a loss of fluid pressure here when the command for 4th gear happens. Reason being that you are now using the same AFL oil (1-2 signal oil) to help the 1-2 solenoid come on that is used for the 2-3 signal oil. Basically AFL oil right. Here is a spring my boss developed a long time ago to help this complaint that you can find in the TTK overhaul kits. I feel in conjunction with a tight AFL bore and using this spring this complaint is generally not an issue. Just a thought. Vince

Jake's Performance

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AFL is just limited pressure oil, it regulates actuator oil to no more than 125 psi. A leak in this circuit doesn't seem to have much affect on solenoid operation as much as loss of torque signal to the boost valve.the solenoids are also somewhat regulated by the solenoid feed holes in the plate that are. 020-.030".
It doesn't take much oil to apply the shift valves. I've never seen so much loss that they wouldn't apply, even on worn VBs.
I would have to look at an old plate to remember what it does exactly different. It's not relevant to my builds since we use our own plate but basically B solenoid oil forces the 1-2 shift valve upshifted no matter the state of the A solenoid. If you kill this by plate mods you could force a 3-1 shift when shifting to 4th.
It could be a bad or missing oring on the B solenoid.

Vince B

iTrader: (1)

I would think that if we had a missing or bad oring on the B solenoid we would not have 3rd gear. Don't know but it seems after talking with a few other builders about this complaint, the issue is a leak in the hydraulic circuits is what I'm saying. I don't think this issue is a mechanical fault in the rotating assemblies with a no 4th gear complaint.

Billy1987

iTrader: (10)

Should i start looking for a new valve body or just buy some new solenoids?

Jake's Performance

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The solenoid fits fairly tight and with the bracket may be enough to give third gear, but the B solenoid operates two shift valves. If the A solenoid has more pressure than B, it will force the 1-2 shift valve to the first position, instead of upshifting the 3-4 SV.

If the snap ring is left off the 4th clutch pack, you would have issues with 4th.

Billy1987

iTrader: (10)

In your opinion do you think it will hurt it to run the trans just leave it in 3rd for now?

Jake's Performance

iTrader: (2)

Potentially,
Why not have your builder do his job and fix it properly?

Vince B

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Jake's Performance

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Back to this Vince, now that I have a decent connection and not on my phone.

If AFL was leaking at the AFL valve, causing a loss of AFL oil to the shift solenoids (and EPC/boost valve) it would show up more so in a situation where only one solenoid is commanded on.
Each solenoid is a leak, approx .080" leak from my studies, being fed a constant supply of AFL oil from a .020-.030" feed hole in the plate. When the solenoid is commanded on, it seals itself and is no longer a leak, causing oil to fill the cavity between the solenoid and the shift valve, shifting the shift valve against spring force to what we'll call the "shifted position".
In the case of the 1-2 shift valve, the shifted position is low gear. It causes what is essential "DRIVE" oil to be blocked at the 1-2 SV, and 2nd oil to be exhausted at the 1-2 SV to pan.
When you release the A solenoid, the 1-2 SV goes to the 2nd gear position, feeding to the intermediate circuit causing a shift to 2nd and also allowing drive oil to reach the 2-3 shift valve so it is prepared for a 2-3 upshift.
2nd gear is default, both solenoids off.
When it shifts to 3rd, the B solenoid comes on, causing the 2-3 SV to move to the "shifted position" which allows DRIVE oil across the 2-3 shift valve to the 3rd gear circuit, and also blocking the 3rd gear exhaust.
BUT...
The B solenoid also forces the 1-2 shift valve to the outboard position, NO MATTER the state of the A solenoid. This is why a stock 93-up 4L80E can actually be held in manual low and the PCM can command a shift all the way to 3rd.
It is also why you can command the A solenoid back on for 4th, and not cause the 1-2 SV to move to the low gear position, exhausting all DRIVE oil, which would cause a return to first gear. Which would feel like neutral since we don't have a band on to cause engine braking in low.

A small leak on the B solenoid circuit, would cause A solenoid pressure to be higher than B solenoid pressure, which could force the 1-2 SV back to low causing the symptoms the OP is experiencing.
It may not cause a loss of 3rd. The B solenoid may have enough pressure to upshift the 2-3 SV, but not enough to counteract the pressure differential of a properly working A circuit.

Keep in mind, commanding 4th gear is both solenoids on, sealing off all leaks of AFL at the solenoids, so 4th should be the best you have as far as an AFL pressure loss not being an issue.

I designed a highly effective transbrake for this unit, so I do know my way around the valve body

Billy1987

iTrader: (10)

The trans guy wont warrenty his work. Which sucks. I drove the car alittle over the weekend. when i shifts into od it pulls for just a second and then starts to slip. But it does try to pull some. Dont know if that helps any but i figured id let you all know.

Jake's Performance

iTrader: (2)

It really sounds like a bad leak in the OD clutch basket with that symptom.
Might as well pull it out.

Send that pig to us, we'll fix it right, dyno it, and get you up and running.

Billy1987

iTrader: (10)

Update.... I have drove the car a few times in the last 2 weeks and i would always leave it in 3rd. After about 50-60 miles on the way home i forgot and put the car in Overdrive.The car shifted just fine and caught me by surprise. But i have about 200 miles on it now and i has shifted perfect.

Vetal

iTrader: (3)

Did the problem with 4th gear ever came back? If not, what could be the problem?