96 Accord Auto Ex No Reverse Zipper sound in D4
No check engine light.
Had to add transmission fluid.
Changed speed sensor
Reverse worked fine for a day or so
Been sitting about a week while timing belt was being changed.. Held fluid.
Now wont shift into reverse again.
Do I need a whole new transmission?
I love my wagon and dont want to see her die

 

Did the car drive fine before the belt replacement?
May have popped an axle out, verify both axles are properly seated.

 

This happened a few days before the belt was replaced. I got off the interstate on the exit it started with the zipper sound and lack of acceleration. Put in D3 got to work. Started fine but no reverse had to push it out the spot. Drove in D3 home. Added fluid it was pretty empty. Changed speed sensor. Worked reverse ok. Still zippered in D4.
Back to no reverse now.
The cam seal was leaking and it got all over it. Water pump was leaking too. It was just that time.
My buddy mentioned the neutral saftey switch?
It doesn't start untill D4 light up amd fuel pump engages. Is it possible its a related ECU issue?

 

There is something wrong with the wiring if you have to select D4 to start.
Remove the center console to access the NSS and verify your shifter cable is also properly adjusted.
Can you remove the key when the car is in gear? You should only be able to remove it with the selector in Park.
Does the gear selection on the gauge cluster light up when selecting gears?
With the ignition turned to II(ON) and you depress the brake pedal, can you hear the interlock solenoid in the center console working? It should make a click when you depress and then again release the brake pedal.

If the fluid was low probably well beyond time to drain and refill.
If the trans is original and has not been serviced and pushing 200K miles, then it is most likely the zipper sound you are hearing is the trans pump cavitating from the sump pickup being blocked with junk.
Drain the trans, if it is mostly dark gunk and slurry, most likely your pump sump pickup is clogged and will need to be cleared to allow normal operation of the transmission again.
Follow Tylers method to clean the pickup if you are positive there is no longer any flow. https://honda-tech.com/forums/honda-.../#post50667457

 

Thank you so much for the help!
The key will come out while running in park never tried on purpose or accident in any other and will only start in park.
When i turn the key and try to start it will crank but it wont start untill the D4 light blinks on and of once. Usually takes about 30 sec to a minute longest ive waited is about 5 maybe 10 minutes and that was after not starting it up for a few days. Once its started the first time rest of the day it starts pretty quick
I do hear the solenoid clicking.
The lights do also work.
Fluid is super dirty just from checking it. And its new.
I changed the transmission fluid when i first purchased the vehicle about 8 years ago and last week the tranny not been serviced in any other way. I can change an alternator, distributor ect basic take it off put new one on kinda stuff, never touched a transmission. Guess im about to learn a bit of something lol
Shes actually pushing 300000! 299118 to be exact.
Motor still sounds great when its not surging in park. Discovered today it only starts that after i hit the brake.

 

Most likely the pin lock for the key is missing or damaged. Possibly from the key cylinder being replaced. If your key is not a 'H' Honda key it may have been replaced, either due to theft damage or worn cylinder.
That is most likely a problem with the ignition switch.
When you turn the ignition switch to II(ON) all the warning lights should come on, the D4 light will illuminate for a moment and at this time you should also hear the fuel pump prime, they will then both drop out and the D4 lamp will go off.
If this does not happen, either the contacts in the ignition switch are worn out(common problem on aged Accords) or the Main Relay is not functioning.
Being the key pin lock is not functioning, I would check the ignition switch itself first. It is either not installed correctly or is simply worn out.
Also when the key is turned to II(ON) and the D4 lamp does not illuminated at prove out(before starting) then start to jiggle the key up down. If the lamp illuminates then it is definitely an ignition switch issue.
That means the brake lamp switch and interlock solenoid are functioning normally.
To fully change the fluid the transmission needs to be drained and refilled 3X.
Usually you would drain, refill and go for a drive, making sure to initiate all gears. Charge each gear circuit from P-1 and then recheck fluid level. If you live in a hilly area have it fulled to the upper portion of the hash mark.
Then repeat.

If after draining and refilling the transmission does not engage, and with nearly 300Kmile, it is most likely that the sump pickup is clogged and will need to be cleared to allow normal operation.

You MIGHT be lucky and be able to clear the clog by draining the transmission.
I would suggest having the car parked level fore-aft, but raise the Left side of the car somewhat to aid in sliding any junk in the sump towards the drain plug on the right side.
If you have just ran the engine, I would suggest getting the car parked as mentioned and leaving it sit for a few hours before draining, this would allow any gunk in the sump to move away from the pickup.

Use generic Dexron II/III(gallon jugs) from your local shop.