5 speed gear noise when under load?

[WildCrustacean]

I have a 96 sr5 5 speed 4runner, 280k ish miles.

Ever since I have owned it there is an audible whine or a ringing kind of noise in some gears but only when I'm really pushing it. 2nd gear is the loudest (and its not really even that loud) but if I'm accelerating hard at the top range of 2nd gear it is pretty noticeable. If I accelerate more gently it doesn't make any sound at all.

I changed the transmission fluid last year and that didn't seem to make any difference.

Hoping someone with more knowledge can comment on this, I realize it's an old truck and has strange noises but I'm more curious than worried right now.

 

[IoN6]

Interested in the replies. Have a new to me '99 Tacoma that the trans seems to be louder than I would have expected.

 

[DaveInDenver]

Does it pop out of gear? Is it hard to shift in to or out of 2nd? Does the whine change with RPM or speed?

What gear lube and weight did you use? Did the old lube look OK and what about debris on the drain plug?

Does the shifter wobble or is engagement solid and sure?

Problem here is there's not just one thing that could cause it. Input countershaft bearings are common wear points. But the main shaft could have excessive play, one or more worn gears or synchros, etc.

You kind of have a choice, though. You can't really know if it's a simple shim or snap ring or thoroughly worn bearings and gears until you pull it out and put eyes on it. Thing is if you do inspect it at 280K it needs some TLC so you might as well rebuild it at that point.

I'd do the easy stuff first. Replace the shifter seat and put in good oil (I've liked Redline MT90 a lot in my trucks). Bleed and set the cluch. Not a lot externally you can do otherwise and those things generally don't point to a specific gear whine. But you might get lucky, never know.

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Or you can turn up the radio and find a different scab to pick at. It's *probably* not bad enough to be catastrophic just yet.

 

[WildCrustacean]

It does not pop out of gear or really feel loose that I can tell, the driving/shifting all feels normal.

It can be difficult to downshift into 1st when moving, but I think that's normal and if I do the double clutch thing and rev the engine a bit it will downshift into 1st no problem.

I put redline MT90 into it last year, and the fluid that came out was definitely old but didn't look that bad to me and I didn't see any metal bits or anything on the drain plug. It did shift noticeably smoother after changing the fluid but the noise was still there.

The only thing I can pinpoint that affects the noise is how loaded the transmission is, which directly correlates to how much gas I give it. The normal place I notice it is like when I'm trying to go from zero to 40 or whatever as fast as possible, I hear the noise when I'm getting ready to shift from 2nd to 3rd with the accelerator down. I also can hear it a little bit in higher gears going up a hill, like for example if I'm on the highway in cruise control at 65 I'll hear a little bit of the noise when I start going up a hill and the transmission starts working harder.

I'll have to look into the shifter seats, and yes I know eventually it will probably need a rebuild but it doesn't seem to me like I'm at that point yet. It doesn't have any symptoms to me that point at something being broken or in immediate danger of exploding or anything.

 

[WildCrustacean]

Or you can turn up the radio and find a different scab to pick at. It's *probably* not bad enough to be catastrophic just yet.

I missed this the first time, and this is what I'll do in the absence of somebody here saying "oh yeah, that noise is the well known 4runner 5 speed noise of impending doom" or something.

 

[DaveInDenver]

Yeah, 1st gear is not synchronized so it will be very difficult to shift into while moving. That's normal and double clutching (e.g. RPM matching) is the right way.

Usually the owner's manual will just say not to use 1st unless you're stopped and to some extent it's right, you shouldn't force it because that can wear the shifter fork.

All your symptoms point to more-or-less normal wear. It's a spectrum that started the day it rolled out of the factory. We use 2nd a lot and accelerate fairly hard in it usually, so it's one that wears faster.

If everything seems normal even if someone could say "It was exactly this bearing" or "That input countershaft gear" that fixed it for them it's probably not bad enough to justify tearing it apart yet. Stay on top of maintenance until grinding, popping out of gear, hard shifting start to show up.

 

[DaveInDenver]

Oh, also forgot to mention, also check your motor mounts and the cross member transmission mount. If the drivetrain isn't true and has a lot of movement that can cause weirdness. I wouldn't think a single gear whine would be due to it but it could explain issues under heavy loads if things are twisting up.

 

[C.Gerdo]

Unfortunately a gl5 gear oil is not good for these manual transmissions.
Many years ago I was having some shifting issues. I switched to the Redline MT90, which is a gl4. Shortly, it shifted easy and was quieter. I won’t use anything else in my transmission.
It’s probably worth the cost to do another change and use the MT90.

I am noticing that I have more noise and vibrations in 5th gear under load, uphills. (266,000 miles).

 

[WildCrustacean]

Unfortunately a gl5 gear oil is not good for these manual transmissions.
Many years ago I was having some shifting issues. I switched to the Redline MT90, which is a gl4. Shortly, it shifted easy and was quieter. I won’t use anything else in my transmission.
It’s probably worth the cost to do another change and use the MT90.

I am noticing that I have more noise and vibrations in 5th gear under load, uphills. (266,000 miles).

I did use the GL4 redline MT90 (after having read about how GL5 might not be the best). It definitely made a difference when I put it in, but didn't eliminate this particular noise.

 

[IoN6]

Yeah, 1st gear is not synchronized...

Almost positive 1st is syncro'd, it is just the most abused.

 

[DaveInDenver]

Almost positive 1st is syncro'd, it is just the most abused.

View attachment 126845

Whatcha know, I've always assumed it was not. This was in my head so I tried and was able to shift down into 1st on my RA60 (2008 Tacoma) last night while moving. I have been assuming something wrong all these years! Googling shows even the H41 has a 1st gear synchro.

One of the vehicles I learn to drive a stick was an 1980 F150 with a T18, 4 speed, 6:1 granny with no synchro. Once you get something into your head it's sometimes impossible to get it out I suppose. One builds up 40 years of brain and muscle memory, it took concentration to *make* myself ignore that voice telling me do not shift into 1st slowing towards a stop light...

FWIW, the T19 that's only a few years younger was helical cut 1st and synchronized. So that mistaken assumption I made hasn't been true for a very loonnngggg time even in old farm trucks.

 

[IoN6]

Funny you mention the T18, that is also where my experience with un-syncro'd 1st comes from. The CJ has a T18a (totally do not recall what the (a) means) with the granny first. Though I think it has a 6.32:1 ratio.

 

[Rzeppa]

I had that tranny in my 1977 F-150 too. The Land Cruiser J30 3-Speed is also non-synchro 1st.

I took the H42 out of my '76 '40 and put it in my ''71 '40. I didn't kit it or anything, just put it in as-is with 272k on the clock. I've added another 50k or so since then and now it is starting to get a little tough to get into 1st and 2nd, pretty sure the synchros are probably well-worn.