Willi Hoffmann

A friend got a 98 Civic, tranny failed. When you start the car the tranny works fine for some minutes, shifts firm, then fails. Got code p0700 TCS, p0740 TCC Solonoid, p0730 incorrect gear ratio. I think it is an "electric" problem. Anybody any idea ?

Former User

If you reset the ECU, do the codes return?

nub

OP says the transmission failed. Was it replaced?

I've never owned an auto Honda and never put any research into them so don't take this as gosel by any means.

If it was replaced was it replaced by one from the same generation car? My "understanding" is the control scheme for OBD1 & 2 are different.

There's also the possibility it was replaced with a CVT which isn't compatible with traditional geared auto trans. controls.

Former User

Still worth resetting ECU to see whether both codes return.

Check the VIN secured to the transmission. Compare to VIN on chassis. Do they agree?

What Civic trim?

nub

Agreed 100%.

I'm just throwing some "possibilities" out there since the supplied info is lacking useful details.

I'll stop now to prevent confusion.

Former User

You're doing fine. I understood your point. My intention was not to criticize.

Willi Hoffmann

Sorry for lack of information. It is an LX with the original transmission. The same problem accured last year once, after topping of the fluid it went away. When you start the car the transmission will shift firm into D or R, drove it only to load on the trailer, then it just fails and act's like it is in N, you can rev up or shift thru the gears, nothing will happen, no signs of slipping, no noises..... will reset codes today and see what happens.... I thought it is some electrical problem as I got 3 codes, not only the p0700. Just never worked before on a Honda transmission..... so happy about all input. Thank you !

Former User

Only two codes are thrown (P0740, P0730) - P0700 is just a generic code to indicate a transmission problem.

Willi Hoffmann

Ok, deleted codes, started car and drove it on the property for a while, tranny failed again WHEN I SHIFTED from forward to reverse, no codes came up, turned ignition off, started engine again and tranny was working fine again. NO CODES ! Could it be the p0740 = Torque Converter Clutch Solonoid Circuit ? Where is the Solonoid located on the transmission.

Former User

I'd recommend that you try 3 drain/refill cycles with Honda ATF with a short drive where you move the shifter through all gears between each cycle.

I wouldn't let the previous codes influence your decisions unless they repeat.

Willi Hoffmann

Ok, did as follows:
Waited for the new oil yesterday and swapped the Torque Converter Solonoid and the Speed Sensor from other transmission. Tranny failed again ( feels like tranny in N ) when shifting after a while. No Check Engine Light ! Turning Ignition off for at least 5 seconds and starting again car will drive like normal. Changed today fluid 3 times and drove it between changes for like 1 mile and shifted thru gears, everything seemed to be fine. After last change I took it out for longer test drive. First miles everything perfect, pushed kick down several times..... after like 7 miles Tranny failed again, after kick down it was not shifting up again, like sticking in this gear, then felt completly like beeing shifted to neutral. Check Engine Light came on, Code 0700 and 0730. When I shut car down for more then 5 seconds and restart, it will drive normal for like 1/2 mile, then fail again..... what now ? new tranny ? Thank you !

Former User

See diagrams:

Willi Hoffmann

Change the Shifting and Linear Solonoid.... failed again after a couple of miles, 700 and 730. It is better after everything I do, but guess will start to pull tomorrow the tranny Anyhow learned a lot, worked never before on a Honda tranny. The only way to survive as mechanic - keep learning !

Former User

People usually do auto ---> manual tranny swaps so you may be able to fine a good auto replacement for a low price.

94EG8

The transmission is bad. I have never seen one of those transmissions throw codes that was ever fixed by replacing solenoids. Any time you see incorrect gear ratio codes it tells you one of 2 things: The wrong transmission was used (using an EX trans in a CX/DX/LX will do this) or the transmission is slipping.