Whiny manual trans... why??

I have a 01 Tacoma V6/5spd/4wd - The transmission has a whiney sound in first, second and a little bit in 3rd gears. Kinda like the whine when you go in reverse. Anyone else have this problem? Anyone know how much, and what type of fluid goes in this so i can check to see if its low? thank you!


EDIT. I opened up the FILL plug on the tranny and it was full of clean gear oil. Any ideas why it has a whine?

 

synchros are going out.

 

Are you serious? People like you shouldnt be allowed to post answers on any forum. Do you even know what a synchro is, or what it does?? My transmission shifts perfectly. Works perfect in every way, besides a little whining in 1st-3rd gears. That has nothing to do with synchros.

Im not trying to be a dick, but unless you know what your talking about, please dont reply. All you do is cost people unnecessary time/money.

 

Straight cut gears.


*Edit. Maybe. I know straight cut gears whine, and I'm pretty sure reverse is straight cut.

 

So is this just a normal whine, or do you think maybe there is a defect in my gears? I recently had a 2001 5 speed 4cylinder 4wd taco, and I didnt notice it whining like this one does. But yes, it does sound like reverse, just not as loud.

 

That's weird, mine doesn't do that. Maybe you just need to change the fluid. I hear Red Line MT-90 is the best. Im not sure on the capacity though.

 

Oil level looked good. I took out the "check" plug bolt, and clean fluid ran out of it. maybe there is a chance they used the wrong viscosity? Maybe I will drain it and try the redline stuff. Can you get that at a parts store like oreilly's or autozone? thanks!

 

I think you have to get it online but im not sure.

 

If oil was coming out of the fill plug that isn't too good. From what i've read, you're supposed to fill it just before the level reaches the fill plug.

I've looked for Redline around here and haven't been able to find. Cheapest place I found it after shipping was from here

It's $9 shipping for the entire order, so if you need to do a fluid swap anytime in the near future, I'd just buy everything at once.

Trans needs 2.3qt of GL4 or GL5 (many people say use GL4, which is what the MT-90 I linked is)

 

All the forward gears in any manual transmission are helical gears so they maintain constant contact as they interact meaning smooth silent operation.

Reverse requires the use of an idler gear to move into place and cause the transmission to rotate backwards. The idler gear can only move in place if the gears are straight cut. Straight cut gears mesh very well, especially with current manufacturing but they don't maintain 100% contact during transfer from one tooth to another. This create impacts with every tooth transfer and hence the characteristic whine.

As your transmission wears, especially in the lower gears that have the most force applied to the teeth, the helical gears can start wearing to the point where their constant contact isn't so constant anymore. It will never whine like reverse but there may be minor transfers, so 99.9% contact.

If the truck has a lot of miles on it, you accelerate like a jack rabbit, or your transmission is improperly maintained this will happen sooner. Not accusing you of any of these, especially since you might not be the original owner. The only way to stop it is to replace the transmission or wear ear plugs.

Might not be your problem but from your symptoms, chances are pretty high this is it.

 

sounds like a pretty good explanation to me. i just bought the truck, and it has 109k miles on it. Im unaware of how the previous owners drove it. I will change the fluid, and put in the proper amount, and if that doesnt help, i guess I will have to live with it. Its not THAT bad, but it was enough to notice, and would like to correct if possible. Thank you all for your replies!

 

mine does it too. bought it at 60k. i havent noticed any problems from it and just assumed that was the way it is. i have put about 25k on it since then

 

mmmm.....it's a truck! With a truck tranny.

 

mine does this too. my previous tacomas did it as well. so its not bad that its does it?

nagelg.. where are you at in MN