Ranwal

Recently bought a 1999 Honda Accord with a h23a swap done. Bought it knowing it needed some TLC but the transmission recently has been acting up.

• Reverse not working (off and on)
• Sporatic hard downshifts
• Staying inbetween gears (contant lurch, cyclic rev)
• Slipping
• (2) works. Have to drive max of 40mph at 4K rpms
• sometimes not even recognizing gears I put it into manually

All this sounds like an electrical problem or a solenoid problem, not an actual transmission problem. Shift solenoid? Lock solenoid? I have no idea. Thats just the info I've gathered from youtube and google. My question is, where do I check these solenoids on the trans? Also is there a fuse for the transmission control module that could be making it act up? Looked into a 5 speed swap and thats nearly 3500. Any tips or suggestions would be much appreciated!

Ranwal

also wondering what this is. It's not connected on the top of the engine. Gets warm, does feel like it might be a vacuum line. it comes up from the bottom(ish) area of the engine and merges into two lines not connected...

MAD_MIKE

First, Check fluid level.
Warm up the drivetrain, place the trans in every gear for 5-10 seconds, Return to Park and with the engine still running, pull the dipstick, wipe it clean, reinsert, wait 3 seconds and pull again, it should be withing the hash marks if not top off, repeat above and recheck. If level has stabilized go for a drive, note if there is any difference in function.

Second, check for any codes, be it at the CEL or D4 light. Although these cars still have the two wire test connector for OBD1 codes, it would be best to get a proper OBDII scanner/code reader to get the exact DTC code.
All the warning lights should come on for a few moments when the key is turned to II(ON) and should turn off when the engine is started. If no lights at all then the bulbs may be missing or burned out.

98-02 4spd ATs are known for issues. Check that the gear selector switch is still located on the transmission right side cover, and that it is wired and working correctly. If this is damaged or out of adjustment the PCM may not command an up shift.

Back probe the TPS, this may go bad but not set a code. Verify there are no flat or dead spots in the voltage readout, it should be linear.

The solenoids are located on the front face of the transmission, they are in pairs.
#7 is the linear control, these affect pressure in the system.
Adjusting solenoid ratio “a” will affect:
Reverse servo control and reverse engagement
1st Clutch forward engagement
3rd Clutch feed and 2-3 upshift
TCC lockup RPM slip rate in 3rd onl
Adjusting solenoid ratio “B” will affect:
2nd Clutch and 1-2 upshift
4th Clutch and 3-4 upshift
TCC slip rate in 4th
However I would not touch these until you are sure everything else is fine, also you will need a pressure gauge to monitor changes.

#9 is lockup/4th control
#11 and #12 are for shifting 1-3 IIRC

Pull #15 and #16 and make sure they are clean of any ferrous material on the tips, these are shaft speed sensors. If they are coated in material they cannot inform the PCM what speeds the shafts are at and the PCM may not command an upshift.



2nd gear is limp mode.
You need to find out what the PCM is doing.

Also, have you had any work done prior to the transmisison acting up?

That hose in you last picture should attach to the valve cover where that large rubber hose is. One end attaches to the valve cover and the other attaches to the air intake before the throttle body. That is the air inlet for the PCV system.

Ranwal

Ran the OBDII Sensor on it today at a friends house and got the following two codes

P0720 Output shaft speed sensor
P0740 Torque converter clutch solenoid circuit

Ordered the part for P0720 and it should be at auto zone tomorrow. The technician at autozone couldnt find the part for the second error code. I haven't found any luck researching it myself. Clean the transmission today and all connectors as well. Everything looks fine. Mechanic pulled off the solenoids and check for damage and everything checked out. The two error codes sound like just what it is doing. I am still getting the flashing d4 light and driving in 2nd around the military base (speed is 25mph so no harm to trans really) I know the flashing d4 light usually means TCU error. Hoping the two OBDII codes are the only thing wrong. Does anyone have any information on the Torque converter clutch solenoid circuit? ... location? Wires? Part number? I will be installing the speed sensor to see if that helps any. If not I'll be taking it to a local transmission shop and paying through the nose. So I'm trying to catch the errors myself if they can be operator fixed. Thanks for the information!

MAD_MIKE

The dreaded P0740 code...
Pepper your angus, a rebuild is coming...
http://www.sonnax.com/articles/20-Ov...ters-740-Codes
You will need to have the trans rebuild with a proper PRV...
http://www.sonnax.com/parts/2753

andyz

Why is it that a circuit code is thrown and not some Solenoid Performance code

MAD_MIKE

Because there is an issue with the circuits performance, not the solenoid.

Solenoids are working properly, its a default in the PRV overshooting which does not allow fluid flow. No fluid flow causes the fluid in the TC to not recirculate, the constant shearing of the fluid from the turbines creates friction and heat, combined with the low flow there is dragging of the TCC which compounds the problem. Eventually it just cooks the fluid, wears the TCC, and overheats the TC.

andyz

Is this the same as P0743 Torque Converter Clutch (TCC) Solenoid Circuit Electrical

Ranwal

What I am failing to understand is why this is calling for a transmission overhaul? All my error codes suggest elictrical. I ordered the P0720 Output shaft speed sensor and will put it on tomorrow. Also looking for a part for the other error code...anyone have a link?

I finally got around this morning to raising my car to change the trans fluid. Changed it, put some stop slip fluid in it. Ran it a couple hours later and it was shifting roughly fine. Torque converter is still giving me shift. When I don't give it enough throttle at higer speeds 40+ it will lurch again. Until the torque converter locks up right after more throttle. I'm going to install that part tomorrow and hope it helps. I have the money to rebuild the transmission or do the 5 speed swap. But it just seems like a hassle if I can save the transmission it already has. Anyone have the part link for the P0740 Torque converter clutch solenoid circuit?

andyz

This seems ominous. Not sure what they want you to do instead.

http://engine-codes.com/tsb/tsb.php?...tsb_make=honda

andyz

This seems really good:

http://books.google.com/books?id=I1L...20code&f=false

I suspect the Honda code is a bit generic, actually gives the one 0740 for all the other ones you see in that group like 0741, *Slip Detected*