[Lifted79CJ7]

I made a quick video on how to change the oil front and rear differentials my 4.7L, 4X4 Grand Cherokee and thought I would share here since they have the same drive train. Hope this helps someone out if they have never done their own maintenance before!

http://www.youtube.com/watch?v=rNdHmpQQJJQ

:stickpoke:
Jack



Warning: I am not a professional and not held liable for any damages to any vehicle that you work on or have someone work on. This is only for demonstration purposes on how I have done work on my own vehicle and may have left out some critical information. Please refer to your dealer before performing any maintenance or work on your own.

 

[gord181]

Diff Service at Dealer

Thanks for the video.

I was at the dealer for regular maintenance and the service rep told me that I should consider getting the front/rear diff. oil changed out. I have an '07 LTD HEMI with only 25,000 miles on it.

They wanted $315.00 all in just for the diff. work.

Do you know if any warranty would be voided if I did the work myself?

Thanks

 

[Lifted79CJ7]

It shouldn't be voided as long as you stick with products that are approved for your vehicle and as long as you keep receipts and mileage with it. That's what I have been doing. I would still consult with your warranty provider first though. The dealer is a rip because they have to pay all the staff, plus insurance through the roof, chemical pick up fee's, blah, blah,blah. Do it yourself and return the used oil to pep boys. This took me about 30 or 45 minutes to do in my garage - well worth saving several hundred dollars in my book!

 

[gord181]

Thanks for the info!

 

[PhilCommanderPayne]

Hi, I know this is an old thread. thanks for the link and just to be sure, the front diff doesn't have a separate lower drain plug, you have to pump out what's in there from the same plug you fill it from? Cheers

 

[drm4633]

are you sure? i made the same assumption when i changed mine but the service manual says otherwise.

 

[PhilCommanderPayne]

I only thought that was the case from the link that was in the first post. I would have thought there would have been a drain plug but not sure where. Could the drain plug you reference there be for the transfer case?

Are there any images that would show it?

 

[consumedbywater]

There is a drain plug for the front diff, on the passenger side. It takes the same 14mm allen key to take out as the fill plug does.

 

[PhilCommanderPayne]

There is a drain plug for the front diff, on the passenger side. It takes the same 14mm allen key to take out as the fill plug does.

Amazing, thanks, will take a look for it. Makes sense there would be!

This next question may seem a bit stupid (as I presume ou should always keep it as level as poss) but am I able to drain the front diffs and transfer case having jacked up the front slightly so I can get under a bit easier or will that affect the drain and refill amounts badly? Probably only talking 10cm raise or something. Same for the rear diff. Thanks

 

[rblapham]

The Front Diff and transfer case have drain plugs - think a 1/2 inch drive ratchet fits the diff one and possibly the transfer case. The rear diff does not have a drain plug - remove cover to drain. To put oil back in get one of those pumps that fit oil bottles - cheap at auto parts store or many retail stores.

 

[consumedbywater]

Amazing, thanks, will take a look for it. Makes sense there would be!

This next question may seem a bit stupid (as I presume ou should always keep it as level as poss) but am I able to drain the front diffs and transfer case having jacked up the front slightly so I can get under a bit easier or will that affect the drain and refill amounts badly? Probably only talking 10cm raise or something. Same for the rear diff. Thanks

Jacking the front up slightly shouldn't impact draining too badly. The transfer case should drain more quickly when jacked up, since the drain plug points towards the rear of the vehicle, and you may get more fluid out overall. You might get slightly less out of your front diff when draining it, but you should be fine.

As far as refilling both units, you'll want to have the Jeep as close to ride height as possible. Since you're filling until oil comes out of the fill port, any changes in fill port height may cause the gears to run dry or foam up the oil, causing lubrication problems.

Instead of jacking the car up for this procedure, I'd recommend getting a few blocks to drive the Jeep up on. If you have a block under each wheel, you'll still gain the necessary height to fit underneath, but it'll still be sitting level.

 

[PhilCommanderPayne]

Amazing, thanks, will take a look for it. Makes sense there would be!

This next question may seem a bit stupid (as I presume ou should always keep it as level as poss) but am I able to drain the front diffs and transfer case having jacked up the front slightly so I can get under a bit easier or will that affect the drain and refill amounts badly? Probably only talking 10cm raise or something. Same for the rear diff. Thanks

Jacking the front up slightly shouldn't impact draining too badly. The transfer case should drain more quickly when jacked up, since the drain plug points towards the rear of the vehicle, and you may get more fluid out overall. You might get slightly less out of your front diff when draining it, but you should be fine.

As far as refilling both units, you'll want to have the Jeep as close to ride height as possible. Since you're filling until oil comes out of the fill port, any changes in fill port height may cause the gears to run dry or foam up the oil, causing lubrication problems.

Instead of jacking the car up for this procedure, I'd recommend getting a few blocks to drive the Jeep up on. If you have a block under each wheel, you'll still gain the necessary height to fit underneath, but it'll still be sitting level.

Thanks! I’m going to attack, front and rear diffs and transfercase in the next couple of days!