question Help Zetor 7341 grinding in reverse

[CanZetor]

Hello all!
I have a 1999 Zetor 7341 that has been making a grinding noise anytime you are backing down a hill. It will not grind if the tractor is backing up a hill or pushing something. I purchased the tractor three years ago and it was grinding then. I recently split the tractor this past winter and replaced all of the bearings and a few shafts in the speed reverser assembly. It was good for about five months but is now starting to grind again. I will attach some photos of the reverse gear that seems to have some play in it. I'm unsure if there are any adjustments that could be made as to not wear the bearings out.


Here are a couple of pics of the speed reverser assembly. the gear that is circled has a bit of play up and down. Maybe 3/16". I am not positive what is grinding.

 

[Renze]

I would suspect the needle bearing in the idler gear.

 

[CanZetor]

I would suspect the needle bearing in the idler gear.

I will check that out. Kind of odd that it went bad so fast though. I had changed the bearings in the idler gear too about five months ago.

I noticed that in the diagram of the speed reverser that the idler gear is mounted on the other side of the transmission, opposite mine. Probably nothing because I do not see how it could be flipped. Here is a picture of the diagram anyways.

 

[CanZetor]

Needle bearing in the idler gear checked out okay. Any other suggestions?

 

[Joachim]

The grinding noise only occurs when reversing and without load (downhill)?

Are you sure it's not coming from the portals? The large tapered roller bearings on the axle shaft are adjustable and need to be checked and adjusted from time to time.

So, can you pinpoint the noise more precisely?

 

[CanZetor]

The grinding noise only occurs when reversing and without load (downhill)?

Are you sure it's not coming from the portals? The large tapered roller bearings on the axle shaft are adjustable and need to be checked and adjusted from time to time.

So, can you pinpoint the noise more precisely?

Hey, thanks for the reply. Yes, grinding noise only occurs when reversing and without load (downhill). I did something which may be frowned upon and drove the tractor with the transmission cover off. It was difficult to see past all of the oil being flung up but I'm pretty sure it is the gear that I circled in my previous reply. It has a bit of play up and down, maybe 3/16", I cant figure out why those bearings would have gone bad so fast.

I will certainly check out those portals though. Where are they located exactly? Is the adjustment described in the service manual ?

Thanks again.

 

[Renze]

It was difficult to see past all of the oil being flung up but I'm pretty sure it is the gear that I circled in my previous reply. It has a bit of play up and down, maybe 3/16", I cant figure out why those bearings would have gone bad so fast.

3/16" is 4.7mm... UP and Down ?
Then i assume spigot bearing no. 57
Forward, the shafts aŕe connected directly by the shift collar. In reverse, the spigot bearing has to center the gears, when it is gone, it causes misalignment which causes noise and explains the grinding into gear.

Has your tractor been run with too low oil level, somewhere in time ? Because the needle bearings are the first to starve from lubrication at extremely low oil level

 

[CanZetor]

Tractor has not been run low on oil since I have changed all of the bearings. Unsure if it has been prior to that as I have only had it for a couple of years. Interesting guess with the spigot bearing (no.57). When I split the tractor this past winter that spigot bearing and retaining clip (no.42) were totally missing. I ended up cutting open the hydraulic filter and found the remnants in there. It badly scored the clutch shaft (no.2 and the driving shaft (no.15). I ended up replacing both and all corresponding bearings.

There must be some sort of improper adjustment somewhere because it is getting plenty of oil flung up onto those shafts. I will post some pictures later of the shafts that I replaced. Hope this information helps, I'm quite new to the world of Zetor mostly been working on David Brown's up till this point.

 

[Robertzetor3340]

What is the oil you are using for the Gear/Hydraulic oil ?
You may need to use the GL4 oil and not use the GL5 oil.
I use the SAE 75W-90 Synthetic Gear Oil, API GL-4 Gear/Hydraulic oil.
The GL5 oil may eat any copper parts.

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