JD 790 Front wheel lockup

[MinnyMoMan]

Hello everyone am new here. Have searched for a problem I am having with my 790. The left front wheel (as you are sitting on tractor) locks up, mostly in reverse. If you drive forward a little it works fine, then later it will lock again. It is getting worse so going to fix, had the front wheel gear box open at the wheel to look at gears as one thread mentioned but they are fine. So before going any further wanted to get peoples advice. Any knowledge or advice would be helpful, thank you.

 

[RoyJackson]

You wrote you opened up the front pumpkin and didn't see any problems. That's good...now it's time to pull the wheel and hub (if you haven't already) and see what's going on there.

When I had my 790, I was fortunate enough to have no problems with the front end (which are rare, considering the number of 790's that were sold), so I never had to pull anything apart other then when shimmed the hydraulics and routine maintenance.

 

[MinnyMoMan]

I meant i already took wheel off and took that cover off, those gears are fine, have not opened the center trans axle yet

 

[Don87]

Maybe the first question that should be asked is:
Are the tires the correct size for the tractor. Improper tire size can cause that also.

 

[MinnyMoMan]

Tires are the right size, now having problems getting the center hub out, will come out about a half inch but that is about it. Anybody have this problem? Any suggestions? Have had plenty of these out but never one that hung up like this.



Thanks for your help

 

[RoyJackson]

Tires are the right size, now having problems getting the center hub out, will come out about a half inch but that is about it. Anybody have this problem? Any suggestions? Have had plenty of these out but never one that hung up like this.



Thanks for your help

If I recall, there's a circlip you have to pull before you can take it down. Wish I still had my service manual, but that went when I sold my 790.
Anyway, if no one here can respond wth a picture of the components, you can try JD Parts (https://registration.deere.com/Sign...ontroller.SessionStartup?userAction=fromEmail) and you'll find a number of illustrated break down pictures that might help.
You will have to register, BTW.

 

[Tractor Pilot]

MinnyMoMan,

Attached are some pictures from the JD790 service manual on disassembling the MFWD differential and shafts. Let me know if you need more pictures from the manual.

Bruce

 

[kennyd]

Roy, When are you gonna learn how to do it?:laughing:

 

[RoyJackson]

Roy, When are you gonna learn how to do it?:laughing:

Actually, I forgot my JD Parts password!!

 

[godaddy]

U have to pull both front axles out. Then the center section will come out. I have just had to rebuild the whole front end on mine about 3 months ago. More than likely one of the gears one the left side hub is broke and a broken off tooth is getting caught in between the gears. That is why it stops turning. Mine was doing this at one time when it broke. Easy to fix just "VERY EXSPENSIVE". Each of the outside gears are close to $90 each. More than likely u will need bearing also, $20 each. If u have a ring/pinion issue, $770 for just the ring/pinion. I am willing to bet u have a broke outter gear. What ever it is, if it was me knowing ? I know by having this exact samething happen to me, I would pull it all apart. Check everything, clean all metal out(it's in there) and replace what needs be. Do not drive tractor anymore or u will be spending more money. Like i said, this has just happened to me and close to $1500 dollars later, with me doing all the work, all is well for now! U need to buy u a shop manual 4 your tractor also. Good info in it. Good luck!