horrid grinding sounds going for reverse
 

OK here is the problem I been getting for sometime and I made some mistakes I am going to clear up ASAP as I feel rather dumb when I found more info. But I still must post this. I have stock 1983 LE, 12a engine, transmission is stock nothing modded or anything.

At cold or not running, I can shift to all gears, reverse and neutral very well. Running at neutral, I hear a whirling sound with a little bit of marbles rolling time to time and it sounds like its running with the flywheel or something and when I press down the clutch, I can hear it disengage. I feel its normal since there are no other odd noises. But with the volume of this sound might be a part of can be my high idle issue which I will post a bit later. When I drive the car a bit, everything shifts and reverse go in smoothly. I guess once it gets hot lets say about a good 5 or 7 miles on the road, I put the car in reverse, I am locked out as it seems and its grinding a bit. I can feel the teeth of the gears or something not catching.

From what I done with mistakes I made :scratch: and this is the first time I changed gear oil on a manual, I figured its low since its never been changed since I got the car in 08 and folks just tell me check the oil first before assuming the worst.
Yesterday I got a pump, drained the old oil which stink really bad and is dark. No metal flakes but very little on the magnet which I was told is normal, I used royal purple 75-90w I think and Lucas. I thought I filled it up since I did see some dripping from the "drain hole" stupid me didn't read or listen well so had it half way closed when I was pumping:( where I just found it its the "Fill hole that should be dripping. 1st mistake since I just found out. The car wasn't level, I had it on ramps but its all I have at home which I count as 2nd mistake, 3rd I think I under filled it since I just used one freaking bottle of royal and should be a bit more than from what I read in the Haynes manual says somewhere at 1.7 quarts and I just found out at least 2.6.

From the result of all this, last night, the noise I had which I believe is normally called transmission chatter, It seems to slowly went away and reverse came in stronger than ever and everything was silky smooth as I drove a little bit last night. Today there was no marble noises "chatter" so its all quite, still hear the whirling till I pushing in the clutch and I can hear the sound disengage, and reverse comes in no problem. I drove to my destination which is about 5 miles or so and as soon as I got back home, I get ready to back my car in and it did it again. The grinding is back, the other gears are getting a bit more stiff to shift around, I can't get into reverse and the only I was able to get the car to back up is the shut it off, put it in reverse crank up and go as I did before.

Now I will fix the low gearbox oil and get it to seep from the "fill hole" as I am supposed to soon as I can but as I do this, is there anything else that can be wrong here besides low oil or anything else I need to check here as I get more oil to level everything out? Do I need to rebuild or tear out the tranny to get something replaced or fixed? or is it just low oil and a lesson learned. Be easy on me on this now

update 6-8
 

ok I topped the gear oil the right way with the car level and pumped till the fluid drools from the filler hole. Let the car warm up a bit and took it for a test drive and so far same thing as before. The shifting gets rather resistant to shift and reverse gear was grinding just a little bit at first but engages in. Once it got warmed up even more, either some gears feel resistant then some feel smooth. Basically a lot of hit and miss going on with the grinding reverse and just won't let me shift in.
The noise factor is minimum, not loud at all and is getting better and better. So far I used Lucas 75-90w to top off and a half quart with a advance auto synthetic brand to top off with the same grade.

Overall I guess this means rebuild and I feel like taking chances to win the lotto and have my 7 ripped apart and rebuild from the ground up anew. But since I haven't heard much from here yet, I still question. What will be the next thing to do in a rebuild or if I need one? Is this the synchros not catching? And since I am on a sad budget with a low paying job, how much does it cost for anyone to rebuild myself with a experienced partner vs. the cost for a specialist to fix like certain limbs or my soul??

Feel free to answer and if I don't make sense just ask and I will try to clear things up

It will be tricky to get the gears right if you choose to rebuild the gearbox yourself, i know what you mean by tight budget though and i don't know every thing about gear boxes but i think for what it's worth, save yourself the time and get a nice second hand gearbox and install that yourself. Then if you want you can sell your gearbox to someone for the right price to make up for some of the money you've spent. I'd say the reverse gear in your car has had its day and like all parts it's going to need a replacement one day

How much did get for your gearbox and where did you go to get one? Out here I feel that it be very difficult to get a savaged box in some recycle areas as to me, some of them don't care about a car that old or those that do care and know how to treat a 7 really won't get this issue as the original owner. This is just me on feel or opinion than experiance, I know this can happen to any original owner, even with the love, care, and know how to keep these cars up.
But on subject, If I get a rebuild kit and have a specialist to have at it as I know the gearboxes isn't anything too "alien" to a good specialist compared to the engine as far as how it works or build, have you ever found a quote on how much it will cost before you came to you our final solution on replacing?
From what I see so far, getting a gearbox from ebay seems good in buying price but the shipping can kill my wallet unless I can try hard to find local but so far, I'm not having any luck online as of yet.

try the classified sections in this forum, thats where i got mine.

also, check this link out to help identify your tranny problem:

http://www.mazdatrix.com/g2.htm

Thanks on the site there, I forgot about mazdatrix. It even Identified a part that just fell out of my the last time I drove it last week:( It was my split air pipe......That might be another issue with my high idle, I may doubt from what it does but who knows. But I haven't found the classified section yet but its 4am here so I will check soon enough.