4 speed noises .. help!

[blue66cuda]

I have a 340, 4 speed in my 66 cuda. The trans was just been put in within the last few months and immediately I noticed it made noise in neutral. My previous 4 speed (another story for another day) made the same noise so at first I thought that it must be normal. It's kind of a grinding/ gears working kind of noise that goes away when I push the clutch in. My mechanic says " it's a mechanical device and it's gonna make a certain amount of noise." It think that's bull. He basically just acts like there isn't a problem. Everyone I talk to says there should be no noise in neutral. My clutch pedal vibrates in between shifting gears and I do get some vibration in the handle as well. It shifts fine but over all the trans feels like it's wound up pretty tight, if that make sense.

Resently the same mechanic put an open 8 3/4 rearend in the car for me, changed from a 7.25 and now the trans makes a weird low whine when I push hard in first gear. I don't know if it's related to the rearend but it didn't do it before the rear end was put in.

so I have some issues.. I've never owned or driven a 4 speed car before I owned this one so I have nothing to go on but I have a hard time believing Plymouth made transmissions that made "a certain amount of noise"

Honestly I need to drive/ride and/ or hear what a proper 4 speed is supposed to sound like. Or I need to have someone besides my mechanic drive mine and give me an assessment. I'm starting not trust mechanics anymore so I'd rather haves someone that works on their own car check it out.. If anyone in the Los angeles area can help me out , i would be super grateful. I'm in Sherman Oaks but I'll drive the car anywhere within reason.

If any one has suggestions, info or ideas please hit me up.
thanks

 

[RedFish]

You probably just need to replace the bearings in the trans. The front bearing will make a noise when in neutral and no load on it. Push in the clutch pedal and the noise will stop or get much quieter. Just the oposite symtom of a bad release ( throw out ) bearing.
Whine in low gear probably is due to the rear gear change.

 

[mod5v]

Possibly the driveshaft is to long putting pressure on the mainshaft? should be able to push the yoke in 1/2-3/4" when at rest and weight is on wheels.

 

[demon seed]

Ask your mechanic this, when he went to a shorter drive shaft (which you have to when going to an 8 3/4) where did he position the tranny slip yoke on the splines before taking the tranny yoke to pinion yoke centerline measurement. If you see his eyes get all wonky like he's thinking to hard or he just can't come up with the answer don't drive the car and find yourself another drive line mechanic.

Terry

 

[Rob R]

Cluster gear(or counter shaft gear) thrust washers are worn.That's the most common problem when it comes to what you describe