John Deere 7800 Powerquad: metal parts in transmission oil

[yamahahonda]

Hi,

It seems that, unfortunately, our JD 7800 will need to have the differential and/or gearbox repaired. We were in the middle of changing the hydraulic-transmission oil and everything was going well until we removed the oil line on the front left side of the differential case. As seen in this picture:

https://imgur.com/WfnIXCw

We found metal parts in the oil - smaller pieces have come out together with the drained oil, while "T" looking part and few others were kinda stuck near the drain hole, so we were able to reach them and remove them with a magnet:

https://imgur.com/a/tECYUyG

We bough this tractor around 3 years ago and we changed the oil and filters at that time. The tractor haven't even reached the 1500 hours yet (as written in the manual for the transmission oil change) but we decided to change it this year, since we are servicing the tractor and changing other fluids anyway.

We had some strange problems with transmission oil pressure in 2019 but changing the transmission oil pressure sensor appeared to have fixed them. Other than that, the tractor seemed to be working fine, all the gears, differential, PTO worked, we did not notice any weird noises or transmission behavior. The previous owner also told us that he did not have any problems with it. The hourmeter on the instrumental panel shows ~11,000 hours.

Anyway, the local John Deere dealer won't be able to come until the next week. Maybe someone have seen something similar and knows what part could have broken? The "T" metal part is somewhere around 4 cm in length. All the bits are hard and do not bend at all.

I've checked through the whole John Deere Parts Catalog for 7800 Powerquad with MFWD online and I did not manage to find anything that could resemble these metal parts.

 

[davidroberts30]

bearing cage?

 

[forblue]

As Dave stated looks very much like roller bearing cage, certainly wants looking at sap and not use it till you find problem, rollers in bearings will not usually break due to hardness but cages will and do, what will happen is rollers bunch up on one side putting stress on shaft or where they are used, did you check to see if large roller bearings are used and or if dealer has any in stock if so, as it could narrow search down.

 

[Ronnie MacD]

Hi ,I’ve just had the same problem,john Deere 6200,the worst bearing in whole tractor to disintegrate,the pinion bearing in my case.Bearing cage parts passed through to power quad after oil change / filter change .
Big job as powerquad and gearbox have to come out,both back wheel turrents off ,brakes dismantle,pick up hitch to come off,back housing plate and handbrake to dismantle to remove diff,to access 5 bolts that hold pinion shaft to diff housing.
I can upload photos of most of the proceedure,it may be different to your tractor hopefully to remove move pinion bearing,About £180 for bearing and £3200 for second hand power quad in my case and days of Labour ,£600 in gaskets etc .
if your lucky it could be a diff bearing which is much easier to replace.

 

[davidroberts30]

Ouch

 

[yamahahonda]

Thanks davidroberts30 and forblue for your replies, it appears that I somehow overlooked the parts catalog and I can now clearly see that these are the broken bearing cage pieces.

 

[yamahahonda]

Hi ,I’ve just had the same problem,john Deere 6200,the worst bearing in whole tractor to disintegrate,the pinion bearing in my case.Bearing cage parts passed through to power quad after oil change / filter change .
Big job as powerquad and gearbox have to come out,both back wheel turrents off ,brakes dismantle,pick up hitch to come off,back housing plate and handbrake to dismantle to remove diff,to access 5 bolts that hold pinion shaft to diff housing.
I can upload photos of most of the proceedure,it may be different to your tractor hopefully to remove move pinion bearing,About £180 for bearing and £3200 for second hand power quad in my case and days of Labour ,£600 in gaskets etc .
if your lucky it could be a diff bearing which is much easier to replace.

Thanks for your detailed reply. Wow, I can only image how big of a job that was. I'll be crossing my fingers for a diff bearing failure, because I'm certain that me and my mate would not be able to find time to do a complete transmission and differential overhaul ourselves. Also, we have never fixed anything on this tractor ourselves because simply we did not need to. And having worked only on (and with) soviet tractors before, such a huge task of dismantling the whole rear end of the "western" tractor apart and fixing a transmission and differential is very daunting.

I'm also curious did you notice this bearing failure while working with the tractor? Something like unusual behaviour of the transmission or differential? Some strange noises or something?

 

[Deerefarmer]

Fairly straightforward job if you endeavor to give it a try. Best if you don't use it til you get it repaired .
Hopefully you get fortunate and only need to open the a b c d gearbox

 

[yamahahonda]

So, an update. Our 7800 has been at the JD dealer since last week, and I'm relieved to say that these metal parts were leftovers from a previous failure/repair. It seems that it was the differential that needed to be repaired sometime in the past, and whoever did it, somehow forgot to do a proper cleanup.

All the parts in rear axle and differential are in good condition. We did not have any major problems with transmission, but since the whole rear end of the tractor is disassembled anyway, we might as well have it thoroughly checked and replace some parts if needed. We also plan to change the brake discs, while we're at it.

Thanks guys for taking your time to reply to this thread.