Transmission Whine in Third Only - '76 Spider

[mPedro08]

I got this car with an extra tranny but I have no way to determine if the one in the car is the original or this spare. As far as I know the spare is junk.....The car actually came, as many do, with two boxes of parts in the trunk!

Now to my question.

The transmission shifts fine, does not pop out of gear or exhibit any other negative tendencies. It is however significantly more noisy in third gear than all other gears. In fact, that is the only gear I would consider noisy at all. Since the third gear is on the same shaft as several other gears not making noise, any ideas what the issue might be....or is this a normal thing? I thought bearing at first but with it being on the same shaft....not so sure.

I know my other car seems to have a noisier third gear than the rest, particularly under acceleration so maybe this is something quirky about these cars also?

Again, never pops out of gear or anything....just kinda loud in third.

Thanks in advance for any ideas,

Peter.

[puddin]

my 78 has a whiny 3rd gear too.. just used thicker fluid GL-1 80w-90 and still there-- went to 50w synth and still there-- gotta be something wrong with bearing shaft sleeves or the gear itself-- mine is the orig trans --

not too worried about it - gonna run it till the clutch burns up and rebuild the trans will it's out

[seabeelt]

It is more than likely a bearing.. You have to look at the power transfer diagrams to get a better idea about torque pressure on the gear and then the bearing, also dont forget that third is tuning alot faster than fourth and thus the bearing may be complaining because of that. Just a thought

[puddin]

i just drained the 50W motor oil and overfilled with the GL-1 90W and it quieted down a bit. shifts smoother too.

[jctucker]

Whining in a particular gear seems to usually be the gear itself. There may be a chip or an unusual wear pattern on the teeth.