Quick transmission question

[gloomys13]

So, i have a 89 ka24e 5spd s13, and sometimes when i throw it into reverse and back up it'll grind and kind of vibrate. Though, I don't get why sometimes it'll grind and sometimes just not. So, am i right assuming is a bad synchro. If it is, why it'll do it and sometimes just not?

[coupe240sxguy]

grind... from where exactly?

[gloomys13]

^^^Well, to me it feels as if it grinds/vibrates from the differential or something from the back, it may be just me or the transmission could be it actually. The transmission itself shifts good into reverse with no grinding, but is when i start backing up that this deep grind starts. Weird, like i said sometimes it'll do it and sometimes just not. Thats why i'm a little puzzle.

[conno707]

Mine does this same exact thing...
It does it more the longer i go in reverse.
I just pulled my ka and the transmission. The transmission had metal flakes in it. But if that were the problem it should've grinded in every gear.

[coupe240sxguy]

are u leaking brake fliud... check level. possibly the brakes just a thought

[gloomys13]

No, i'm not leaking any kind of fluid and all my fluid levels are good. I don't think its the transmission cause i just replace the oil with Red-line, like 3 weeks ago. Also if it was a bad synchro it'll do it every single time, right. I will go thoroughly tomorrow and see what i can figure out.

[corn322]

Sometimes it's the rear brakes making noise.

[rustest86]

reverse doesnt have a synchro, its a straight cut gear. ive been into more transmissions lately than ive wanted too. im putting money on the rear brakes.its a real common problem with sliding calipers, normally they do that when the slide pin is sticking or stuck. and what your hearing is the harmonics from the pads rubbing when there not suppose too. check the slide pins and grease them with the silicone brake grease and you should be good