6 speed 4th gear grind/whine

Hi all,

I have a 2012 Tacoma with the 6 speed manual and a few months ago it grinded on me when I was shifting from 3rd to 4th and has done it 2 or 3 more times since then. There's also a bit of a whining sound when accelerating in 4th gear (seems to go away when I take my foot off the gas), and I only ever hear this in 4th gear, no other gears. The whining sound in 4th has been there since the truck was either new or close to new but it never grinded going into 4th until a few months ago.

The truck has 96,500km on it and I've owned it since new. I have only ever run Redline MT-90 in the transmission. I switched it over when the truck was a couple months old and it's been changed a couple times since (the last time was about 2 months ago) so it's not a case of the fluid needing to be changed or anything like that.

I'm going to bring it up with the dealer when it goes in for its next service in a couple weeks but I highly doubt they'll be able to replicate the grind since it only does it very occasionally (for now anyway). They should be able to hear the slight whining sound it makes in 4th though.

Does anyone else with the 6 speed have these issues with 4th gear? Just trying to find out if I'm the only one having these problems as I'm really wondering if I have some sort of problem developing with this transmission. The powertrain warranty is up in 3,500km so I'm hoping if there's a problem I can get it covered before the warranty expires.

Thanks.

 

No problem here - 60k miles so far. I've only had the gears grind a couple times (don't remember what gears), but in my case it was user error at the time - foot slipped or some such mistake.

 

None for me.
I have 55k and use redline also.
Mine does not and has never whined at all.
That would have worried me if my truck was new. I would have taken it to the dealer then.
Whining usually means a bearing or ? Is going.

 

If I'm accelerating moderately fast I can here a faint whine when in 3rd gear. It's the engine, not the transmission. A Australian friend one time asked if I had a supercharger when he heard it. It's not super loud and actually sounds kinda cool. Is the sound you hear definitely from the transmission or is it from the engine?

 

Yeah it's just a faint whine on mine as well, it's not excessively loud or anything, it's a little hard to hear it if there's a lot of road noise from wet roads, etc. I can't really tell if it's the engine rather than the transmission where the noise is coming from, I just figured it was the transmission since I only ever hear it in 4th gear. If it was the engine wouldn't I be hearing it in all gears?

I called the dealership that I bought the truck from about it a couple days ago and the service advisor I talked to said the whine in 4th gear is normal because it's the direct drive gear on the 6 speed. I don't know about that, I always thought 5th was the direct drive gear on the 6 speed since 6th is the overdrive gear. He also said that running the Redline MT-90 fluid is probably causing issues and the only 6 speed failures he's ever seen were ones where people were running Redline or some other non-OEM fluid. I don't believe for a second that running Redline instead of OEM oil would cause more wear on the transmission. Besides it says in the manual to run 75-90 GL-4 or GL-5 fluid (which Redline is) NOT to only run Toyota OEM fluid so if there is an issue they're not going to get out of covering it. Anyway it's going in on Wednesday and they're going to take it for a drive. Not sure if that will help since it's only grinded going into 4th 2 or 3 times in the past few months so it probably won't do it when they drive it. I'm just worried because it never once grinded going into 4th before and I'm afraid this could be the start of something that might get worse.

 

Dealer is full of it.
Not only does it not matter that u r not running OEM fluid,but the Redline is better for our trans.
It meets all req'd specs.
I have run both,and the redline is much better for shifting.
Fluid level is much more important.

 

I don't know what's causing your issue but I can confirm that 5th gear is direct drive in that transmission.