Been noticing a very slight whine that increases in pitch based on engine load/rpm. Its not super loud but definitely noticeable especially when I was on the trail or when I give it a lot of gas. I have a new alt, timing belt, wp, fan clutch, serp tensioner and pulley. Also have flushed steering fluid and replaced with proper atf

A separate issue that I'm not sure is connected, but I have also been noticing is the trans hesitates to shift into 5th and will go up to like 2500 or more rpm and hold there for like 15 secs before shifting. Its not abrupt or harsh, just hesitating. Sometimes it shifts immediately sometimes it hesitates. I feel like I noticed this only after the bigger tires so maybe its that. I have also done a full drain and fill with absolutely zero change.

What do you guys think?

I had a similar issue with my 3rd gen, and oddly enough it was a u-joint in the front of the driveshaft. I knew it was bad. I had the typical vibration but I had no clue where the whining was coming from. It changed in pitch/volume based on load/rpm as well. Put a new driveshaft with good u-joints in it and it went completely away.

This I have no help on. Mine does the same thing every now and again, for not quite so long, so I assume (hope?) it's something normal.

I keep mine greased frequently and see little to no change at all, but next time I grease it Ill pay close attention to see if I hear something.

Just got back from driving to lunch. It wouldn't shift out for like 30sec-1min this time. Its like its rightttt on the edge of shifting but it just wont do it unless I go up another 20 mph or so. Really annoying

The whine is not likely a drive shaft if it happens at trail speeds - the shaft wouldn't be spinning fast enough to whine. Rumble or growl maybe.
I would suspect:
- low power steering fluid
- failing PS pump
- alternator whine in the radio/audio system due to a failing diode - switch the audio system off to check that.
- alternator bearing whine.

I'm not saying it's the case with him, but mine most certainly was whining from take-off. It actually went away the faster I went.

My thought is a failing power steering pump as well. The fluid level is fine though I just checked that and its still bright cherry red (fresh). The alternator is a reman Denso and its not showing any signs of wear thus far with alittle over 10k on it. No flickering lights, correct voltage, etc.

Ill have to turn off the radio and see if that does anything, but to me it sounds mechanical. Almost outside or under the vehicle

My whine got progressively louder and people kept telling me it was PS pump, but mine ended up being the drive belt idler pulley - it seems yours is new though so maybe not. I'd try to isolate where the sound is coming from - a low tech way we used was a long screwdriver up against the bolts with our ears up next to it to see which one was actually emanating the sound.

The hesitation thing seems to happen to me as well...I was gonna try to pull the ETCS and EFI fuses to reset the ECU/transmission "learning" values - maybe you could try that.

I don't have a new idler pulley, but I do have a new tensioner pulley and tensioner bracket etc. Maybe I'll swap the idler pulley and belt for $hits and giggles.

Can you go into more depth on how I do the reset? I can give that a try.

Do transmissions whine? I'm wondering if they might be related.

Some other things to check concerning the whine:
- does it do it when the vehicle is in neutral, or only when moving?
- If only when moving, is it ground speed related, or engine speed related?
- Is it worse when you're trying to turn (steer) the front wheels?
- You noticed it on the trail. Does it do it in high range as well as low range? It''s not uncommon for transfer cases to whine more in low range than in high.

Basically, gears can whine, hydraulics can whine, bearings can whine, electronics can whine. You just have to isolate them one by one.

Idler pulley is a quick swap and pretty cheap, so that might be worth it anyway (I used the Dayco 89154). I got a the Bando drive belt (6PK2240) for under $15 and it's been fine as well.

I believe it's just pulling those 2 fuses in the fuse box near the battery for a few minutes (with the truck off and a key out of the car) and then putting the key in the on position for about 10 seconds before starting it. Otherwise you could also pull the negative terminal on the battery for a few minutes for the same results. Might be worth a shot for shits and giggles as well.

Pulley ordered! We shall see what that does if anything...belt is only a few months over a year old but I may change that too while im in there...

If that doesn't fix it I think I may take to mech and see what he says. Shes going to the shop soon for headers anyways.

1. Haven't checked SUPER thoroughly, but I definitely notice it way more in drive than N.
2. What do you mean by this, can you elaborate? Does this mean coasting vs constant held speed?
3. Turning doesn't seem to affect anything, but I will check this further.
4. It is more noticeable in 4Lo I feel...also I felt like the hotter the truck got on the trail the more noticeable the whine was....

So I did alittle checking tonight and it’s definitely more noticeable in D or R. It changes pitch slightly in N and isn’t really there all that much. I did this test by holding the brake down and giving throttle. Not moving at all, but putting the engine under load.

Turning doesn’t seem to affect it as much as change in RPM does.

Noise goes away almost immediately after throttle is let off of. Picks back up immediately when on the gas especially at lower speeds in lower gears 1,2,3. Especially with a quick tap of the throttle. More noticeable when engine is cold as well. But still there when warm.

Haven’t checked 4LO yet. Will report back tomorrow

bump