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7745 with noisy transmission

J

juney68

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juney68
I just purchased a 7745 at auction. This is my first Zetor and have never even operateed one before now. It has a very noisy transmission and I was wondering if this is normal for these tractors or do I have a problem. With the clutch pedal pushed in it is quiet. In neutral, with clutch pedal out, there is some noise, but not too bad. When operated in first through fourth, it is very noisy. When in 5th, it is still some noise, but much less than 1st through 4th. The noise is not a grinding or knocking noise, but more of a gear whining/meshing noise. I do not have a manual yet, so I am not sure if maybe it has the wrong oil in it or something simple like that. Does it take hydraulic or gear oil and is the transmission and rear end oil housing all together or seperate ? Any help would be greatly appreciated.
Thanks, juney68
 
first of all check the oil

we purchased a forklift which had the same problem. when the clutch was in it was quiet when clutch was out it was scream and bang. when we took of the gearbox lid we found all beaings had finished.

usually wed use SUTO oil (super universal tractor oil) this does backends and is very good.
 
I agree with Matthew.
The transmission, rear end and hydraulics all use the same oil.
The dipstick is under a rubber plug in the floor covering between your feet, attached to the filler plug. It takes 34 lt. to the top mark and 27 to the middlemark with the dipstick screwed in. dont fill to the top mark unless you are tipping a very large trailer or working on steep land.
These gearboxes are not normally noisy.
Dave
 
My 6320 Zetor has always had a noisy transmisson but ran well.
 
Hmm...

If you have 4WD connected, it keeps some noice at high speeds, like when H4 and H5 is connected...
 
Ok, thanks to everyone for all the ideas. It was about 8 ltr's low on oil so I added but this made no difference. I also cannot tell any difference when its in 4wd, and I have not had it on hard surfaces in 4wd. I did take the magnet out and check and clean it. It did have some metal on it, but nothing big. Just very fine particles. Is this normal ? Is there a cover plate on this tractor like was talked about on the forklift that I can take off to check the bearings ? I have to say there is no banging, just more of a whine. Also, I tried all the different selections for the PTO and hyd pump and this also made no difference. Any ideas as to why it is quiet in 5th ? Thanks. juney
 
Mike,

I have been using my 6245 (equipped with No-Spin diff lock)several winters all the time 4wd on. I have studded ice chains on front wheel and no chains at rear. Im driving a lot at roads, asphalt coated too, pulling log trailer.
So im doing all wrong

Now it has 4500 hours on it and i opened it few years ago, but there was only fine surface worn on the gears where 4wd shaft comes out from gearbox.

I think many other brand would not last in my use

But Zetor is still going and going.....
 
small metal particles id expect. if your oil is all ok well it may be ok. for instance david brown tractors have noisy transmissions due to stright cut teeth on the gears. dont know if all models are though. my 3545 whines in 4th and 5th.

matthew
 
The 5. gear locks the clutsshaft to the main gearshaft,innside it is a small bearing that cold make the noice, it stops moving vhen in 5.geare.It cold olso be the syncro for the 5. gear thats whinig.
 
Ok, thanks again. I think what 4911 is saying may be what it is. I was thinking something like this myself, as I know alot of transmissions(maybe all) are direct in high gear. I never thought of the synchroniser aspect though, this also makes sense. I assuming 4911, that I have to pull the engine out to make these repairs ? Also, Dave mentioned not filling the oil to the top mark. I actually overfilled it some and now I have oil dripping out from between the transmission and engine, in the clutch area. Is this why you said not to overfill or do I have a seal bad ? Thanks, juney.
 
You probably have a seal that is leaking. I'm afraid you have to split the tractor to get at them. This is not a big deal if you have some help and the tools, and it lets you check the clutch while its apart. The seals are on the gearbox main shaft and the PTO shaft in the centre of the main shaft.
The reason not to fill to top mark unless necessary is that these seals and the seals into the brakes tend to seep when they get old and hard and the oil is permanently above them.
Where are you located ?
Dave
 
I also wanted to ask about the centrifugal oil filter. This is my first experience with these. I took it apart and cleaned the black grime off the inside wall. I'm assuming this is what you are supposed to do ? I still don't fully understand how it works though. ??? juney
 
Juney,
It spins when the oil is being forced out of the 2 jets. The dirt deposits in the oil are thrown outwards and stick to the wall as you saw, any bits of metal or other rubbish in the oil is prevented from going back into the sump by the gauze filter in the centre.
You were right to clean off the black gunk, just make sure its all clean and the holes in the jets are clear and remember that the unit is dynamically balanced , so it is important to make sure that the 2 marks on the bottom flanges are lined up before you do up the big nut on top.
Dave
(From SW UK)
 
Thanks Dave,
I've got a couple more questions. For the clutch throw out bearing, it says lubricate every 200hrs(i think). Do you just use engine oil here and how much ? Also, the pto lever on the left side of the seat says something like 5 min/max on it. What does this mean ? Is there a fuse diagram download anywhere online ? Where is the best place/prices on manuals ? Thanks for all of your help. juney
 
Juney
For the clutch throughout bearing use just a few drops of your normal engime or transmission oil.
When you lift the PTO clutch lever it has the same effect as the foot pedal has on the main clutch,so leaving it in the up position will lead to premature wear and possible overheating not to mention wear on the throwout bearing, so its a good idea to not leave it up at all unless its just , for example, when you are using a muckspreader and you want to turn at the end of a row. Do you know that if you put the air compressor in gear once the air is up , when you push the main clutch pedal all the way down it will operate the PTO clutch, also the lever will then be air assisted to make it easier to lift.
I'll scan a page from the ownwers manual with the fuse diagram, and attach it to the next message, Im not good at multi tasking and would probably lose this one if I tried it here !
Dave

 
Juney, Here is , I hope, a pic of the main fuse box. you may have another smaller one as well - that works items in the cab roof in UK spec tractors, but I don't know about US ones


Type "workshop manual" in the search box at the top of the forum page for places to get a book
Forget that !!
Try this, Scoll down to "dont know" then Type "Zetor" in the "search" box
Dave
 
Thanks Dave, That worked. I'm assuming that #8 is a spare as mine has nothing connected to it. I think I'm going to go ahead and try to use it some before I tear it apart to check the bearings. Really cold here right now. Is there any type of glow plugs or pre heater or cold weather starting techniques for these tractors. I hate ether. Also, you talked about the compressor, is it ok to leave the pump engaged all the time ?
Thanks juney
 
To aid cold starting in sub zero tempratures a block heater can be fitted the part number is 6901-1730
 
No, no heater as standard, in UK at least, I have no experience of temps like yours, if it gets to -2 c here we think its cold.
Seriously though, maybe one of the contributers from a cold country will conmment.
Some people leave the compressor running all the time, but we tend to use it only when we want the air.
Dave
 
A cold starting device is fitted on these tractors. when you start push the hand throttle to full speed. it vill turn over a valve in the diesel pump, wich give you more diesel than normal in the starting moment. also this device will automatically keep the rpm around 1000.1300 rpm until engine is warm. Here in norway we often have cold tempratures but i never had any problems starting my 7745 in temps as low as -25C you could use the block heater if fitted its much better for the engine. it will also ease the start. These tractors are equipped here in norway as standard with a heater that works wery well. Also if your tractor is not fitted with an air reservoir tank. You must not have the compressor running without the air hose connected. or else u may blow the compressor. also the lubrication of the clutch The dealer ship here in norway says not to lubricate it . it will make more of a mess in the clutch housing than it will do good. Usually there is a sweat in the clutch housing so there is no need to add oil. the lube and pipe wich to lube through was removed on later models because it wasnt necesseary.The noise in your transmission could come from the hydraulic pump, if the shift lever for 540/1000 rpm is set to 1000 rpm.
 
Thanks guys ! Your expertise is greatly appreciated. Although it provoked more questions. About the air tank, I would like to add this. Any recommendations about size,location,plumbing,relief valves, etc would be helpful. Maybe even a picture. On the hyd pump causing the noise, I had it in all the different positions and it made no difference. Also, my cab heater fan is not working. How do I access this ? I read something about tilting the cab roof but not sure how to do this or if I need to. I did not see any fuse labled for this Dave. Do you know which one ? Thanks to all. juney
 
Are you sure you havn't got an air tank? It would be under the floor to the left of the gearbox, About 1' dia and 2 1/2' long.There's a guage showing its pressure on the dash.
Maybe us spec tractors arn't fitted with this.
To lift the cab roof, stand on the bonnet (us=hood) and undo the 4 bolts around the bottom of the white roof then lift it up, it's hinged at the back.
Look at Mike's post of a couple of days ago about the fuses for the cab roof.
Our tractor has another smaller fuse box which is for the roof only, located just above the main one. the fans take a lot of juice, so when you get them working dont leave them running without the engine going.
Dave

 
As your tractor is nott fitted with air tank from factory. it doesent have airbrakes (optional) or air trailer brakes. thats why there is no need for a reservoir tank. to get to the cabin heater fans you have to unscrev two srews in the corners of the roof console inside the cab. rater big screws with a big plastic washer. then the roof will sving down. som consoles have hinges some dont. you can see the hinges just above the windscreen if they are fitted. it also depends if its the narrow or wide cab thats fitted. be care ful with the front window as you swing it down. if its not hinged. the whole thing will come down. be careful.also the fuses in the top fusebox wich is for the heater and fans. im not sure wich of them. it varies slightly after wich country you are in and what kind of equipment is fitted.the relays for the fans are located near the fans in the roof console. They may very well be the cause of your problem. You check if they work by turning the switch and listen for a click. be sure to check the fuses before you do. hope this will help you .by the way this procedure im giving you is for the narrow cab with the steel roof. Daves reply is for the wide cab with fiberglass roof
 
Thanks guys, I checked and mine does not have a air tank. If I just added one would I have to put some type of pressure relief valve on it ? On the cab fans, it turned out to be the fuses. I had only checked the fuses in the lower box. Mine has the fiberglass roof. Do you need to oil these motors ? Thanks, juney
 
yes you would have to fit a pressure relief valve. no need to oil motors in the fans. when they are worn out you will hear a loud ratteling noise. because the fan blades touch the fans interior walls.
 
What psi or bar should this relief valve be set at ?
 
if you buy the original its preset from factory. but dont mount the air tank you dont need it....... do you. its more trouble than its worth if you ask mee
 
To carry on from the previous post, What do you need an air tank for?. The factory tank does not allow air stored to be used for anything other than air brakes on a trailer and air assistance for the hand clutch and foot pto operation, so if you only need it for tyre inflation then your current system works the same as it would with a tank.
Dave
 
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