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Magnum 7220 trans prob


PJW360
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Hi

looking for some expert advice on a magnum 7220

i’ll try to keep as brief as possible

i’m UK based and own a tidy 8000hr 1997 7220 Pro European spec w/o creep purchased s/h from Sweden 2 1/2 yrs ago it has run great until now

i serviced it 18 mths ish ago and found a lot of swarf like metal in the suction screen thinking maybe a previous repair as internals looked clean and oil like new

checked accumulators and has performed fine until now when the transmission lost drive

pressure tested fine so drained oil removed screen small amount of metal found but not much but discovered master clutch had popped Circlip out so removed g/boxes stripped range to find

master clutch issue

park lock cover ,broken pawl pivot/marked constant mesh gear

mfwd not good because 4 small Allen screws from backing plate sheared off

high range clutch plates darkened but no blueing/scuffing on separator plates

med/low clutches look really good

I haven’t stripped speed box yet but have removed bearing housing cover to reveal a nicked 1st seal on output shaft

i have no intention of getting rid of the tractor so want to repair properly

other than the obvious parts that need replacing like seals gaskets what about clutch plates and bearings-thrusts/needles if looking ok

and best place to source parts does any one do overhaul gasket /seal kit as uk case parts supplies are telling me to give them list of parts required listing every part /o-ring/seal/gasket required which as you will know there are many

Any help greatfully received

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I can't answer your question but I would mention that if Euro spec and especially if higher speed transmission park paw and constant mesh gears are different than USA spec park paw. Picture of the two side by side. There is other differences also but many things are the same 

IMG_20220905_072602016.jpg

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10 hours ago, PJW360 said:

other than the obvious parts that need replacing like seals gaskets what about clutch plates and bearings-thrusts/needles if looking ok

and best place to source parts does any one do overhaul gasket /seal kit as uk case parts supplies are telling me to give them list of parts required listing every part /o-ring/seal/gasket required which as you will know there are many

I am not aware of any "kit" for seals and o-rings. I have always just looked up and itemized each shaft, listing what I need. Some of the thrust needles between gears have been subbed to a composite wear washers in favor of needle bearings.

Make sure you have good service info and follow it closely, clutch cups need to be properly indexed on shafts so drillings for oil pressure line up. I like to "air test" each shaft on the bench, then again when it's installed in transmission. If you keep air testing as you assemble, you are moving any potential problem to the "outside" document your tests.  

Best of luck...!!

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Thanks for the replies

bitty I had seen your post on euro/USA parts the other day which is very useful to know 

cihtech I do have a good dealer shop manual to follow so hopefully have the info to follow and thanks for the tips

its interesting you mentioned a update on the thrust bearings to wear washers do they cause trouble

its the things like that I’m trying to find out what is advisable to replace as any body I spoke to in the uk hasn’t  been a great deal of help with one dealer engineer saying he wouldn’t worry to much about all the seals as they last a long time

lack of experience as not so popular tractor in the uk especially in my area I expect

So was there any updates on the master clutch or is that just what happens with wear

to my mind it’s common sense to replace all orings/seals while your in there

clutch packs my manual says replace friction plates if a clutch is dismantled again would you just replace every thing or leave if in good condition 

bearings obviously the bigger taper ones if clean up ok I think I would reuse but what about the smaller needle bearings did they ever give trouble and the thrust bearings as have already been mentioned updated

sorry to be a pain but I like to do a job right the first time as you know the amount of work involved

one more prob I’m having is with the hydraulic trailer brake valve when you apply the foot brake normally the trailer brakes surge on and off(pulse)but do hold when brake pedal pushed really hard

i have stripped cleaned inspected the valve and the only thing I can see is where the tractor left right signal lines come in they have a steel check ball I’m assuming to check the tractor signals from crossing seem to be restricting oil flow into the valve

i have been in touch with Bosch rexroth but they came back to me saying they don’t have any info any more as valve is to old any body experienced with this

many thanks

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On the thrust needles versus composite washers, I would have to go back and find / read the bulletin. I no longer work at a dealership so don't have quick access to bulletins, maybe @SDman can shed some quick info on this. Just covered in a recent thread if I am not mistaken. To my knowledge the number in parts book will "sub" to the composite washer where applicable. 

The master clutch piston was changed from (2) anti-rotation tabs to 6. I typically replace all the clutch plates in each clutch. My theory is when you have it in your hand it is never cheaper than right then. We repair a lot of tractors and I struggle to keep everything in mind, but doesn't the Magnum service manual give a wear spec on the thickness of clutch plates? 

I like to change the seals & o-rings, as they get compressed, embedded with debris (from normal wear) and hard over time. To me it's simple, your dollars spent aren't going to be that much more to "know" you done the best you can. 

In US we didn't have trailer brake on 71-8900 series Magnums, couple around that are imported Euro spec tractors that do have the trailer brake. That said haven't needed to troubleshoot / repair one yet. Does your manual cover the trailer brake system? 

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36 minutes ago, CIHTECH said:

On the thrust needles versus composite washers, I would have to go back and find / read the bulletin. I no longer work at a dealership so don't have quick access to bulletins, maybe @SDman can shed some quick info on this. Just covered in a recent thread if I am not mistaken. To my knowledge the number in parts book will "sub" to the composite washer where applicable. 

 

Here you go, sir. Although I believe the gentleman's 7220 should already have the thrust washers in it already.

7100 series thrust washers.png

7100 series thrust washers #2.png

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2 hours ago, CIHTECH said:

In US we didn't have trailer brake on 71-8900 series Magnums, couple around that are imported Euro spec tractors that do have the trailer brake. That said haven't needed to troubleshoot / repair one yet. Does your manual cover the trailer brake system? 

The trailer brake system should be covered in the manual.  I know it is in the MX150/170 OEM manual, and that is essentially the same system the Classic Magnums use.  The term “surge” is a bit vague.  It could be that the system is behaving normally for that type of assisted brake.  I don’t really care for how the Magnum (and MX150/170) brake reacts to operator input.  I have an MX150 on a round baler so plenty of stopping using the brakes.  The problem is that the assist is a second or so behind the pedal input, so the driver hits the pedal, expecting an instant response.  There isn’t any response instantly, so the instinctive reaction is to stand on the pedals harder.  Then about that time the assist catches up and WHAM, the brakes hit and it might feel like the brakes surge, but that isn’t really the case.  I also have an MX135 on a round baler and that has a much more intuitive brake reaction.

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