T-10 low oil

[JohnnyBertone]

Hello all this is my first post here. Been searching google for the last 60+
Hours and can’t find any 100% straight answers on my issue. BW aluminum T-10 leaked all of the fluid out and I had driven it maybe 5 miles before I noticed due to the whine 1st-3rd. Filled back up with 80/90 and it still whines but shifts just like before. Some searches tell me this is a sign of a cooked input shaft bearing, others say “overheated unit” and don’t advise on what to do to fix that. Unit is currently out of the car for a clutch replacement and I’d like to see if anyone else experienced this and if there is any fix short of a full rebuild. I am saving for a TKX 5 speed swap so I’m not about to rebuild this unit to only use it for another 6 months.
Any help is appreciated.

[81Blackbird]

This is what I found on another thread and pretty much says what you mentioned...

"When do you hear the noise. First gear, second gear,etc.
It makes a difference, as these transmissions are not known for being that noisy.
A noise in 1st, 2nd and 3rd gear, but goes away in 4th gear, would indicate a worn main drive bearing, also known as the front input bearing, or just front bearing.
A noise in 4th gear only would then suggest a worn rear bearing, on the output shaft, as the load is imparted on that bearing in 4th gear. Not likely.
When I think of a whine I usually start considering a gear whine, bad pattern from previous bearings worn really really bad, or someone ran the trans low on fluid and the unit overheated."

I had an input shaft bearing on mine making noise years ago.  I was able to repair/replace the bearings myself.  It was my first transmission rebuild and this was way before the internet and You Tube.  I guy on You Tube named Paul has a very good video on how to the the T-10.  In fact I used his video last November to guide me through a complete tear down of a Doug Nash street 5-speed.  If you have the time,  take off the side plate and take a peek.  If the teeth are not blued then it is more likely the bearings are toast.  That can be replaced without digging into your wallet.

[JohnnyBertone]

Yea I saw both the same info and the same guy on YouTube. Was going to use his videos to tear down my “spare” T-10 that has a tooth broken off the input shaft gear, but decided it wasn’t cost effective. Appreciate the reassurance will report back with the hopes that this info can help
Someone in the future 

[70_71_78]

This is what I found on another thread and pretty much says what you mentioned...

"When do you hear the noise. First gear, second gear,etc.
It makes a difference, as these transmissions are not known for being that noisy.
A noise in 1st, 2nd and 3rd gear, but goes away in 4th gear, would indicate a worn main drive bearing, also known as the front input bearing, or just front bearing.
A noise in 4th gear only would then suggest a worn rear bearing, on the output shaft, as the load is imparted on that bearing in 4th gear. Not likely.
When I think of a whine I usually start considering a gear whine, bad pattern from previous bearings worn really really bad, or someone ran the trans low on fluid and the unit overheated."

I am not so sure the above is correct. I suspect that a noise in 1st, 2nd and 3rd gear, but goes away in 4th gear, could have more than one cause. My first suspicion would be the bearing between the input and main shaft, due to the difference in speed between them in the first three speeds. The second cause could be bad bearings or wear to the teeth on the countershaft, as power is transfered through it in the first three gears. but not fourth. I suspect it could still make some noise in fourth, but would probably be more noticable in the lower gears. As power is always applied through the front bearing supporting the input shaft, I suspect that it could make noise at any time, verying greatly with RPM and load, making that one very difficult to single out by sound. When inside a manual, I usually replace every bearing as routine, and give a close inspection to every other part and replace anything that is questionable, I taking things apart twice because I was stingy the first time.
Just my two cents worth.

[firebirdparts]

Well, what they're getting at is the load on the input bearing is gone in 4th gear.  There is a big load placed on that bearing by having to drive the countershaft under power.

I don't know if you like to work on things, but you can dismantle it for free.  It's not trivial to get it back together, but to me it does seem pretty obvious.  I guess that the input bearing may not reveal anything to inspection, but the middle bearing certainly will, and the countershaft bearings also will just come out in your hand as far as I know.

Once you get it apart I suppose you won't wish to reassemble it without a new input bearing.  I guess they're pretty cheap.