More Transmission Noise (?)

[WVBill]

I Have a B6100DT that has developed a noise that seems to come from up in the engine/clutch area rather than back by the gear shift. It seems to be on the right-hand side about where the 3ph hydraulic pump is located. The noise is unaffected by operating the 3ph so even though the noise seems to be coming from that area, I've mentally eliminated the hydraulic pump. Since the noise only happens when I'm driving the tractor and it usually only lasts for 10 sesonds or so at a time, it's hard to pinpoint where it is coming from.

It started a few days ago - the day after I had washed the tractor.

The noise is a "whirring" sound sort of like a little toy car friction drive makes. The noise comes and goes by itself but only when the tractor is moving and only when I'm in high range 2nd or third gear. I can make the noise stop by slowing down a little bit either by pressing the clutch or decreasing the throttle. But niether the clutch or the engine speed alone seems to affect the noise. The pitch of the noise does not change with engine RPMs but the pitch does seem to decrease just a little bit right before it quits.

I'm wondering if the noise is coming from the starter motor being driven by the engine intermittently (?) Maybe by washing the tractor, I "de-greased" it so now it sticks semi-engaged (??) But I don't know where the starter motor is located on this tractor.

 

[looch]

I'm trying to recreate the situation in my head. Let me get a few things straight:

1. The noise only occurs when the tractor is moving (and moving relatively quickly).

2. Pressing the clutch does not make the noise dissappear (except because pressing the clutch causes the tractor to slow down).

A couple of questions. With the tractor stationary and the PTO engaged and running at 540, does the noise still occur? How about jacking the rear wheels and spinning them by hand to see if the noise occurs then?

I could be wrong, but I think the starter would be somewhere around the steering column - like between you and the engine. If it were the starter, the noise should occur even when you are stopped.

 

[WVBill]

<font color=blue>1. The noise only occurs when the tractor is moving (and moving relatively quickly).</font color=blue>

Correct. The noise occurs when I'm driving in high range 2nd (my normal "traveling" gear) and 3rd - but I've not been able to get it to occur in H 1 or any of the low range gears.

<font color=blue>2. Pressing the clutch does not make the noise dissappear (except because pressing the clutch causes the tractor to slow down). </font color=blue>

Correct. The noise does not stop immediately upon pressing the clutch - but it does quite quickly after pressing the clutch - (I assume because the tractor slows down). The noise also stops (and starts) all by itself.

<font color=blue>With the tractor stationary and the PTO engaged and running at 540, does the noise still occur?</font color=blue>

I used the tiller briefly and did not notice the noise while the PTO was engaged - but it was only engaged very briefly and I was stopped/moving very slowly when it was engaged.

<font color=blue>the starter would be somewhere around the steering column - like between you and the engine.</font color=blue>

That is kind of where the noise is coming from - between me and the engine - my steering column is only inches in front of the gear shift which is only inches in front of my.. er... the tractor seat. Is the actual gear box up toward the clutch/engine or is it back right at the gear shift lever (i.e. almost right under the seat)? I assumed it was back at the gear shift lever so I've been menatlly eliminating gear noise as the source.

<font color=blue> If it were the starter, the noise should occur even when you are stopped.</font color=blue>

My thought too - I'm grasping at straws with the starter speculation - trying to relate washing the tractor to somehow causing the noise - which would point to some "external" component like the starter, vice something internal.

<font color=blue>How about jacking the rear wheels and spinning them by hand to see if the noise occurs then?</font color=blue>

I'll try it.

Thanks

 

[Kelvin]

WVBill,
I looked in my shop manual that covers the B6100/B7100 and it doesn't discuss starter location or starter removal. It does talk about rebuilding it. It is a Nippendenso starter.

According to the electrical wiring diagram,
(1) the positive lead off of the battery should go straight to the starter.
(2) There is also a wire from a safety switch (probably the clutch safety switch) that goes straight to another terminal on the starter.

Hope this helps. I have no suggestions for what the noise may be.

Kelvin

 

[Egon]

Could it be the clutch throwout bearing?

Egon

 

[looch]

If it were the throw-out bearing, wouldn't the noise also occur when the tractor is stationary with the PTO engaged?

I saw a tool on Motorweek called a chassis ear - would certainly help id the source of the noise.

Without actually experiencing the problem first hand, it's difficult to offer advice - especially if it turns out to something completely unrelated, like a loose whatchamacallit that only makes noise at a certain engine frequency and vehicle speed.

As an example of things can get crazy, I'll realte the following experience:

A friend of mine was having problems with his car. Everytime he hit the brakes - weird things would happen (lighter would pop out, dome light would come on, etc). We were quite perplexed. We checked connections, wires, fuses - all good. Grasping at straw, we decided to replace the brake light bulbs - fixed everything. Turns out the brake light filament in one of the bulbs broke and fell across the driving light filament causing a short everytime he hit the brakes.

 

[WVBill]

I didn't have time to go out and look at the tractor last night, so I checked out my parts list and my Workshop manual. My WSM shows where the starter motor is (top left-hand side of the bell housing) and how to remove and re-build it. It appears to be one of the very few components on this tractor that can be removed without a complete engine dis-assembly and/or splitting the tractor! /w3tcompact/icons/hmm.gif. This is at least roughly in the location where I think I hear the noise coming from.

The problem with fixing location of the noise is that it only happens while I am driving the tractor so ther's no way I can get my ear-or even a mechanics stethescope to the area.

As soon as I get a chance, I'll "fiddle around with" the starter motor to see if there's any indication that it may be intermittently "engaging" while the tractor is operating.

Thanks for the ideas everyone.

 

[Anonymous Poster]

When you say washing and whining noise, I think of water or cavitation in the hydraulic lines. Is this an HST? If so the hydraulic flow that could create the noise would be speed sensitive/pressure & flow sensitive. Water has a different density than that of Hydraulic fluid, and those braided steel lines have a funny way of resonating.

 

[WVBill]

It's not an HST. The only Hydraulics are the front end loader that has a separate hydraulic system driven by the front PTO and the 3ph hydraulics. The pump for the 3ph is in the general area of the noise but I have operated the 3ph lift wiile the noise was happening and it had no effect. Also, there is no evidence of water in the gear case....

Didn't have a chance to look at it last night... The mystery continues.

 

[krickard]

I have a L3600 GST with Fel and my noise after a lot of looking turned out to be the Pins holding the Front end loader also only time the vibration type noise is heard is when moving and 6th to 8th gear range. and 1800 to 2000 RPM.
a couple of washers stopped this noise.
There is several L-3600 in this area and never see a post of any one using this type any reason? se'ya ken