91 Accord Auto - No Reverse, Grind Sound

[mrdeep2001]

Hey guys,

New fella here, just joined last night. Need some help:

91 honda accord with auto transmission issue - You can move the gear selector to the reverse position, but it makes a grinding sound and it will not move. All forward drive gears will engage. He said the rpms fluctuate a bit when he reaches constant speed (not sure if any speed or just in higher gears used on the highway). Possible torque convertor or lock up solenoid issue?

Also, he was having an issue with the main relay (wouldnt start if warmed up), which we were able to fix thankgs to you guys here!

This is my dads car so I don't know all the details, but, a long time ago he was driving and the car overheated. At the same time or shortly after, the S light was blinking (no codes were pulled). About a year or so later is when the reverse gear issue started to appear, sometimes it would work, other times it wouldn't, until gradually it stopped working altogether.

I found the "Auto Transmission Faq" http://www.cb7tuner.com/vbb/showthread.php?t=179566

I think it is a mechanical issue, but I hoped it was something simple so I ran through the tests there:
There were no codes to pull from the TCU
Examined circuit board for burnt out resistors & Caps, it all looks OK
Both solenoids (lock up & Shift control) will actuate when you apply voltage.
Solenoid resistance read 15.2/15.3 Ohms(within spec of 12-24 Ohms)


In the faq towards the bottom, there's a section about:

Problem: My car won't go in reverse (can't backup.) What is causing it?

Solutions: On car without an electronic transmission, replace fourth gear selector or the affected gear(s). The reverse gear is activated by fluid pressure. Check for an internal clogged fluid. Cars with electronic transmission don't require the shift solenoid to go in reverse.

How do I tell if the transmission is electronic? I would assume electronic b/c it is controlled by the TCU, is this true?

I'm not sure if I understand everything correctly, but are there no solenoids used to engage the reverse gear? Are the shift control solenoids only used for forward driving gears (1, 2, 3, etc)?

I found another thread on another site where a guy was having a similar issue, he went through all these checks, rebuilt the transmission (seals) and it ended up being the reverse gear teeth worn, worn reverse gear fork and something else (reverse gear selector I think). If it is something major like that, I brought up doing a 5spd swap (which is what most of you guys do on here) but I don't think my dad wants to do that.

So any help you guys can give to figure this out is appreciated!

[RyanD]

well i cant post in the tech forum yet, so here goes:

91 honda accord with auto transmission issue - Grinds when you try to put into reverse, but will not go. All forward drive gears will engage. He said the rpms fluctuate a bit when he reaches constant speed (not sure if any speed or just in higher gears used on the highway). Possible torque convertor or lock up solenoid issue?

Also, he was having an issue with the main relay (wouldnt start if warmed up), which we were able to fix thankgs to you guys here!

This is my dads car so I don't know all the details, but, a long time ago he was driving and the car overheated. At the same time or shortly after, the S light was blinking (no codes were pulled). About a year or so later is when the reverse gear issue started to appear, sometimes it would work, other times it wouldn't, until gradually it stopped working altogether.

I found the "Auto Transmission Faq" http://www.cb7tuner.com/vbb/showthre...ight=TCU+codes

I think it is a mechanical issue, but I hoped it was something simple so I ran through the tests there:
There were no codes to pull from the TCU
Examined circuit board for burnt out resistors & Caps, it all looks OK
Both solenoids (lock up & Shift control) will actuate when you apply voltage.
Solenoid resistance read 15.2/15.3 Ohms(within spec of 12-24 Ohms)


In the faq towards the bottom, there's a section about:

Problem: My car won't go in reverse (can't backup.) What is causing it?

Have you changed the fluid? what color is it?

Solutions: On car without an electronic transmission, replace fourth gear selector or the affected gear(s). The reverse gear is activated by fluid pressure. Check for an internal clogged fluid. Cars with electronic transmission don't require the shift solenoid to go in reverse.

How do I tell if the transmission is electronic? I would assume electronic b/c it is controlled by the TCU, is this true?

there are 2 solinoids. the top one is for torque lock up and the bottom one by the dipstick is the shift solonoid. take it off and clean it out

I'm not sure if I understand everything correctly, but are there no solenoids used to engage the reverse gear? Are the shift control solenoids only used for forward driving gears (1, 2, 3, etc)?

I found another thread on another site where a guy was having a similar issue, he went through all these checks, rebuilt the transmission (seals) and it ended up being the reverse gear teeth worn, worn reverse gear fork and something else (reverse gear selector I think). If it is something major like that, I brought up doing a 5spd swap (which is what most of you guys do on here) but I don't think my dad wants to do that.

So any help you guys can give to figure this out is appreciated!

answers are in this color

your TCU could be bad as well

[mrdeep2001]

answers are in this color

your TCU could be bad as well

I'll have to ask my dad about the fluid when he gets home from work.

We took the top solenoid off and cleaned it out (was fine). Bottom one we didn't do b/c it was getting dark out.

You are thinking the TCU could be bad even though the electronic components (resistors, etc) were fine?

[RyanD]

it might be ok. i mis read that part in the OP. i would guess the fluid or that solinoid. when you take it off clean the screen. if that does not help it might be something stuck inside the tranny or its just plain toast.

[10thAnnivCB7]

^ x2 . Any of the transmission lights on ? Like the D4 is on when you're on park ?

[mrdeep2001]

it might be ok. i mis read that part in the OP. i would guess the fluid or that solinoid. when you take it off clean the screen. if that does not help it might be something stuck inside the tranny or its just plain toast.

ill clean up that other solenoid, then fluid

^ x2 . Any of the transmission lights on ? Like the D4 is on when you're on park ?

no lights out of the ordinary, cluster lights up corresponding to gear selector position. No flashing lights (S light or CEL)

[AtLargeCB7]

how do the normal gears feel when you drive down the street?

[mrdeep2001]

ill clean up that other solenoid, then fluid
no lights out of the ordinary, cluster lights up corresponding to gear selector position. No flashing lights (S light or CEL)

Cleaned out the shift control solenoid, seemed ok. Solenoids clicked when applying current.

Here's a video I made for the noise I'm talking about.

http://www.youtube.com/watch?v=93YNp8qjdQw

[10thAnnivCB7]

Damn. Sounds like the purge canister but 100x louder. I've actually never seen this problem before. Don't wanna scare you but try another TCU or 2. I have 3 that are fixed and properly soldered with the hot glue around them so they don't leak.

If that doesn't work you might have to get a remanufactured transmission or a rebuilt. The passage ways might be clogged up.

Can you get someone to look at the back and see if the reverse light are coming on ?

Also the shift linkage might have moved. Mine has a ziptie holding it up. You said that when going from reverse to park it keeps grinding a little bit. Maybe when the cable/linkage is up that far it might not be releasing it fully.

[10thAnnivCB7]

I've been on google for about an hour and i keep seeing that this happens when the synchros go bad. If none of the top suggestions work you might have to buy a new trans or get yours rebuilt. I read that it starts by the car cliking into reverse which I've noticed mine has been doing a lot lately so i might not be far from having this problem.

[mrdeep2001]

Damn. Sounds like the purge canister but 100x louder. I've actually never seen this problem before. Don't wanna scare you but try another TCU or 2. I have 3 that are fixed and properly soldered with the hot glue around them so they don't leak.

If that doesn't work you might have to get a remanufactured transmission or a rebuilt. The passage ways might be clogged up.

Can you get someone to look at the back and see if the reverse light are coming on ?

Also the shift linkage might have moved. Mine has a ziptie holding it up. You said that when going from reverse to park it keeps grinding a little bit. Maybe when the cable/linkage is up that far it might not be releasing it fully.

Shift linkage checked out ok, I forgot to mention I checked that a while back.

Somehow while fidgeting with it, going park reverse neutral drive reverse, it DID go into reverse for a second and the car moved back, but then it like popped out of gear and was making the noise again...

[Accord problems]

Hate to tale you bro but its toast.

[mrdeep2001]

I've been on google for about an hour and i keep seeing that this happens when the synchros go bad. If none of the top suggestions work you might have to buy a new trans or get yours rebuilt. I read that it starts by the car cliking into reverse which I've noticed mine has been doing a lot lately so i might not be far from having this problem.

Yeah I think it is something mechanical inside of the transmission, but I've never really had transmission issues before so I wanted to run through as many tests as I can before needing to open up the tranny, which to be honest, I'm not too confident in doing tranny work as I know that you have VERY tight tolerances between components.

[10thAnnivCB7]

Save up and get a remanufactured one. It should be around the same as getting it rebuilt.

[mrdeep2001]

Hate to tale you bro but its toast.

i got 99 problems but a working transmission isnt one?