When I reverse I hear grinding sound from rear of vehicle?

[kornmanz]

When my car was running and driving it would make a nasty loud grinding noise when I reversed the car. Then it would go away. As I drove the car forward if I let go of the gas I would hear noise coming from under the vehicle and feel vibration. I figured it would be the driveshaft and differential having problems so I lifted it, removed both of them, and took a look at them. They both seem fine. There are no gear problems with the diff. I can't tell what was causing those issues. Can I get any help? I dont wanna order parts and they be the wrong parts.

[Dr.feelgood]

do you have a welded diff

[Yasko]

vvvvvvvvvv

[sbart315]

I have the same exact problem except mine is sorta quiet and is a whining sound. I replaced my diff and it still does it so idk.

It's normal for a manual transmission car to whine in reverse.

[breadbox]

lift the rear up and get under it, while someone else reverses. <You did this right?

[sandcrabsailor]

Breadbox, that's just mean. Not to mention dangerous if some newbie took you seriously.
Kornmanz: If the grinding noise is coming from your rear diff, drain the fluid, replace the fluid, and try again. If it is still grinding, take your pumpkin apart and take a look at the gears. See if there is uneven wear or debris. If there is uneven wear, either take it to a shop or replace the rear diff. If there is debris, rotate everything and see if you can see where the debris came from.
See if you can get some help to determine EXACTLY where the noise is coming from. If you have access to a lift, do it. If you don't, get all 4 wheels off the ground to pinpoint the noise source, but DO NOT get under the car while the wheels are in motion. That's just bad juju.
Good luck and keep us posted.

[AZ89two4Tsx]

Are you sure it's completely going into gear?

[OutToWinPAHC]

Reverse is not syncronized is it?

[johnny butt]

SO lots of s*** to sift through in this thread. MOST of these people are correct, but they need to specify why they are saying what they are saying, so this post will do that:

Please specify if you are hearing a WHINE or a GRIND.

YES it is COMMON for manual transmissions to WHINE when driving in reverse. THIS IS VERY COMMON mostly noticeable on Hondas and other FWD cars because you are so close to the transmission and "differential," but will be faint with a RWD Car but it can still be heard.

as far as a GRIND
NO these 240sxs do NOT have synchronized REVERSE gears.
What that means is this: If your vehicle was moving before you go into reverse (whether it's forward, or slowly moving in reverse in neutral [rolling backwards]) what you MUST DO is put it in 1st or ANY other gear with the clutch still depressed to "sync" it up or STOP the transmission from moving.

If you are MOVING and you put it into reverse before you have put it in any other gear you will hear an INITIAL grind (for lack of syncro and 2 gears meshing up at different speeds [hence: not synced??]), but it should not continue to grind. If it is grinding continuously in reverse, it's probably because the previous owner did not know of this procedure (as most owners have shown here...) and f*** the reverse gear up. No worries though, as long as it still moves your car in reverse when necessary; Not a big deal since you don't drive in reverse a whole lot anyway...

I don't believe the differential is the problem because you would hear the noise constantly (and even in neutral??), not just when going into reverse and then shortly disappearing. You are probably not stopping the transmission (manually, meaning YOURSELF) before you put it in reverse.

[kornmanz]

Well see I started hearing this back when I used to drive the car (Over a year ago). It started having problems where it would make that noise (trust me I stopped before reversing) and I would feel a lot of vibration from underneath the car.

I've recently came across some money to throw into the 240. I've taken the driveshaft and differential out and there appears to be no problems. Which is confusing.

I'm going to replace both and see if that fixes the problem.

[imposible drift]

I have exact the same problem with my S14
but the only difference is that mine is Automatic ABS
And is Whine not Grinding

[kornmanz]

Taking the plug for the fluids out of the diff pumpkin showed me a lot of awesome metal shavings. Going to replace the DIFF this week with a kaaz 2 way.

[mikes13jonz]

is it a grinding or screeching noise? check your rear brakes. mine did the same in reverse, till i changed them. didnt hear that noise agian after that.

[raven2345]

I've got a very loud grinding noise only in reverse, and it only goes away after either going in reverse for a good distance, or pressing the brakes all the way down. When I had the wheels off (car in the the air), I would push the rotor back up against the hub, put car into reverse, and it wouldn't grind. Car is automatic. Check your rear brakes before anything. I haven't fixed mine yet, but I believe it's a defective caliper, or possibly I somehow eff'ed up installing my calipers.