Increased noise in my '99 UZJ100

[truggier]

Hey everyone. Tried to search on this but didn't have much luck.

We recently purchased a 1999 UZJ100 with around 82k miles. We're now close to 85k miles, and recently have noticed increased noise from the vehicle. It sounds as if the engine is revving quite a bit higher, but the tach doesn't show the RPMs as having increased. At first it was intermittent - quiet one moment and then noisy the next - and through the transition from quiet to 'high - rev' mode, the RPMs would stay constant. Now, however, it is making this increased noise all of the time.

I checked the ATF level and that is a bit high (3/8" over full) but the consistency of the ATF looks fine.

I recently replaced the engine oil with Mobil One Synthetic, but I don't see how that could cause this problem. The temperature of the engine remains cool.

The two buttons next to the shifter are not engaged (i.e. the one to give you increased power by waiting to shift to higher gears and the one that lets you start off in second gear) and the overdrive is on.

So far the problem only seems to be the noise, but it is worrisome. I'm out of ideas . Anyone ever run into this before?

Thanks in advance.

 

[ATLcrusher]

Throttle position sensor? (just throwing ideas out)

 

[SWUtah]

Cold be the oil change to Mobil 1, since you don't know the grade of oil that was in it before. The Mobil 1 would clean out the engine. I would do another change using Mobil 1 5w30 in about 5K miles. The noise could be normal, hard to tell on the internet.

 

[spressomon]

Hey everyone. Tried to search on this but didn't have much luck.

We recently purchased a 1999 UZJ100 with around 82k miles. We're now close to 85k miles, and recently have noticed increased noise from the vehicle. It sounds as if the engine is revving quite a bit higher, but the tach doesn't show the RPMs as having increased. At first it was intermittent - quiet one moment and then noisy the next - and through the transition from quiet to 'high - rev' mode, the RPMs would stay constant. Now, however, it is making this increased noise all of the time.

I checked the ATF level and that is a bit high (3/8" over full) but the consistency of the ATF looks fine.

I recently replaced the engine oil with Mobil One Synthetic, but I don't see how that could cause this problem. The temperature of the engine remains cool.

The two buttons next to the shifter are not engaged (i.e. the one to give you increased power by waiting to shift to higher gears and the one that lets you start off in second gear) and the overdrive is on.

So far the problem only seems to be the noise, but it is worrisome. I'm out of ideas . Anyone ever run into this before?

Thanks in advance.

I do know most automatic transimssions are relatively sensitive to the fluid amount. So if yours registers too much fluid I would make this right and see if this is your problem...

 

[NMuzj100]

Mobil 1 is known to increase engine noise on BITOG. This is not neccesarily a bad thing but simply a function of its lower viscosity compared to other oils in the same grade.

Heavier oils mask noise better. Mobil 1 is thinner than most. The upside is that thinner oils are better for gas milage.

Also I doubt that the high ATF is part of your noise problem but my truck ran noticably better when I drained the excess fluid out of mine when I purchased it.

 

[ShottsUZJ100]

Mobil 1 is known to increase engine noise on BITOG. This is not neccesarily a bad thing but simply a function of its lower viscosity compared to other oils in the same grade.

Heavier oils mask noise better. Mobil 1 is thinner than most. The upside is that thinner oils are better for gas milage.

Also I doubt that the high ATF is part of your noise problem but my truck ran noticably better when I drained the excess fluid out of mine when I purchased it.

Not disputing....though my 2001 has run Mobil 1 10-30 for 93K of it's 95K miles. It's silent.

I wonder if he's hearing the added start-up noise we all hear though he hears it all the time? What makes that added noise during cold startups?

 

[ShottsUZJ100]

Hey everyone. Tried to search on this but didn't have much luck.

We recently purchased a 1999 UZJ100 with around 82k miles. We're now close to 85k miles, and recently have noticed increased noise from the vehicle. It sounds as if the engine is revving quite a bit higher, but the tach doesn't show the RPMs as having increased. At first it was intermittent - quiet one moment and then noisy the next - and through the transition from quiet to 'high - rev' mode, the RPMs would stay constant. Now, however, it is making this increased noise all of the time.

I checked the ATF level and that is a bit high (3/8" over full) but the consistency of the ATF looks fine.

I recently replaced the engine oil with Mobil One Synthetic, but I don't see how that could cause this problem. The temperature of the engine remains cool.

The two buttons next to the shifter are not engaged (i.e. the one to give you increased power by waiting to shift to higher gears and the one that lets you start off in second gear) and the overdrive is on.

So far the problem only seems to be the noise, but it is worrisome. I'm out of ideas . Anyone ever run into this before?

Thanks in advance.

Idler bearings? They do wear. My '93 was NOISY all the time. I replaced the main idler and it droped the noise 75%. The bearings inside were shotts.