Thread: Transmission leak and whining 3rd gear

Hey guys, my third gear is whining and it looks like a lot of oil had leaked before it started whining. I noticed a long while a go the striking rod boot was wet but I didnt think it was a big deal. I may have driven it like that for months, until one morning the 3rd gear started whining. I looked under the car and I saw what smelled like my MT90 between the engine block and the transmission bellhousing. What can I do to fix this? I never took the tranny apart, just took it down when doing an engine swap. It's not leaking from the axles, but I see significant amount of oil seepage (maybe about 4 - 5 inches) on the bottom of the bellhousing. Should I just replace the whole thing from a junkyard part? I'm thinking its the input shaft seal (30401J in courtersyparts diagram -- 321 Transmission Case & Clutch Release :: Power Train :: Genuine Nissan Parts :: Sentra / NX Parts (B13) 1991-1994 :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com). Do I need to take the gearstack out to replace it or is it accessbile from the clutch side?

I belive the gear stack has to come out. I did mine a couple years ago

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Finally spotted where the leak was, after replacing the striking rod seal and the driver's side axle seal. I'm suspecting a crack (worst case) or loose bolts. About a few weeks ago I replaced the axle with a rebuilt one, and within a few days I heard a clacking noise like the CV joint was broken, but it wasn't. In retrospect it could have been something that knocked something out of place inside. As of now the symptoms are 3rd gear whine and hard shifting into first. Any guess as to what could have gone wrong?

Here's the pic:



Since it's kinda tricky to remove the pin with the transmission still on the engine, I'm posting these pics to save time next time it needs replaced.

Location of striking rod pin:


To remove striking rod pin do it in two steps: punch out the inner pin then punch out the outer pin
Striking rod pin:


Inner pin punch tool:

Hit the cut off nail on the inner pin and it will slide out.

Outer pin punch tool (it's a battery terminal bolt with rounded tip):

Grind about 1/8" length of the tip of the battery terminal bolt, just to fit in the outer pin. Grind it round (approximately) with a dremel tool. Put the tip inside the outer pin then just hammer it out. The ground tip keeps the punch tool from bouncing off the rod.

You ran it low on oil and probably damaged the internals.. I had a crack on my tranny in the bell housing and it eventually caused 3rd gear to go out and it had a whine at a certain speed.. You need to clean off all that oil so you can even see where its coming from in the first place though

Ok guys, so I put it in a replacement trans from a forum member almost a month ago. After coming back from first drive to work the next morning I noticed a puddle of green shockproof. I was like, "no, it can't be". I really thought it was from the overflow from filling it, which I knew some of it came out of the fill hole, so I kept driving it until this weekend when I noticed another small puddle. Took it off yesterday and found lots of shockproof inside the bellhousing and some seeped out of the top (see below). I found something I didn't expect and wonder if any of you can answer what it was I found in the second picture.



The picture was taken after I cleaned up a lot of the shockproof, but notice how clean the bellhousing looks: thats from tranny oil cleaning it up.

I'm using the original bad tranny for practice, and took the gear stacks off, and found something like this on the input shaft oil seal:



Looks like "half of a ring". Anybody know what that's for? Is it a shim? If it is, won't it deform the sealing surface? Interestingly, the original didn't look like it was not leaking oil into the bellhousing, athough I could be wrong. In the picture the washer is right above it.

That last pic looks like a broken pilot bushing.. if so it shouldnt be in there lol it should be it the hole in the crank..

Do the shafts wobble? You might need to replace the bearing an seal for the input shaft..

I figured out what it is. According to the FSM it's a snap ring. Apparently the input shaft moved over about 1/4" to the "back" of the housing. On the shaft in front of the bearing is a groove that the snap ring sits in. When the shaft moved back it came off the groove so it was just sitting there on the rubber seal. I think that may have made the thud-thud sound I was hearing that sounded like a broken axle. I think that's what gouged the gear cover also. Comparing the gear alignment with the one on the replacement confirms that the whole set of gears on the input shaft is off by quite a bit. Probably why it was hard to put it in first gear and whining third gear. Shafts are not wobbly, so if there's anything good that would be it. I pushed the bearing until I could see the groove and put the snap ring back on and the gears rotate freely. But I'm not sure if I would use it. I also broke the oil pocket on the main shaft, aarrgh. I'll see what caused the leak in the replacement tranny tomorrow.