JD 790 drive shaft

[Robert Bolton]

Hi guys, what is the procedure for removing and replacing the front drive shaft on a 790? I can see that the bolt on the front spline has to be removed but what is under the rubber boot with the two hose clamps? I assume that there is another spline but will I lose fluid and are there any "gotchas" in this process?

Thanks, Robert.

 

[RoyJackson]

This would be a good time to buy a Deere service manual if you're going to tackle this kind of work.
The CD-ROM version (make sure you get the one for your 790!!! There's been 3 revisions to my knowledge) costs about $50 or so.

Have the serial number for your tractor when you go to the dealer.

 

[JimRB]

Does the parts diagram help out? John Deere - Parts Catalog

 

[Robert Bolton]

Thanks Jim. I have not been able to find the driveshaft in the parts book.
Robert

 

[Robert Bolton]

Thanks Roy. It really doesn't look too difficult. I agree with you about the service manual.
Jus asking if anyone else has been through this.
Robert

 

[joecdeere]

Robert, see if this helps -
check your private messages for more
Joe

 

[Robert Bolton]

Thanks, Joe. This helps a lot. My driveshaft must be a little different since it doesn't have the tube covering the shaft.
Robert

 

[Robert Bolton]

Thanks, Joe. This helps a lot. My driveshaft must be a little different since it doesn't have the tube covering the shaft.
Robert

Now I am beginning to think that something is missing. I will try to post pics.
Robert

 

[RoyJackson]

Now I am beginning to think that something is missing. I will try to post pics.
Robert

Sure looks like the tube that covers the drive shaft is missing...probably got dented up when the shaft was bent.

 

[AKfish]

Now I am beginning to think that something is missing. I will try to post pics.
Robert

Yep... your pics tell a story that the previous owner likely had a front end collision (high centered, etc.) on something that damaged the front steering tie rod and the front driveline.

That front shroud (cover) on the driveshaft is pretty important! It's always turning, turning. So, anything you drive through is very prone to getting wound up on the shaft. Tall grass, weeds. Wire! Everything... and something's could be a real problem!

AKfish

 

[beenthere]

Here is the jdparts pic and parts (cover and shaft) if you want.

 

[Tractor Pilot]

Robert,

Here is a picture of the drive shaft on my JD770. Should be similiar to what your JD790 should look like. I would recommend that you not use your 4WD until that shaft is fixed or replaced and a new cover installed.

Bruce

 

[Robert Bolton]

OK Guys. Thanks for all of your help. I now have the front end/driveshaft problems fixed. See pic. Ran me about $320.00 for parts. If I knew then what I know now I could have saved about $60.00 by making the tube shield out of 2" electrical PVC. Oh well...live and learn. Thanks again for all your help.
Robert

 

[Tractor Pilot]

Robert,

If you haven't already, there is a lot of information on this forum to read about how to best operate your JD790 to reduce the risk of breaking the front gears.

Bruce

 

[RoyJackson]

Robert,

If you haven't already, there is a lot of information on this forum to read about how to best operate your JD790 to reduce the risk of breaking the front gears.

Bruce

Yep...and one good thing to remember is the tractor is better at pulling heavy loads going forward, rather then backing up.
Another...use adequate ballast on the 3PH when you're using the loader.

IIRC, those gears in the front differential cost another TBNer about $1500.