4x4 Rear End swap

[csamuels]

I have had pinion seal leak for several months and finally took the time to replace the rear seal. The rear end now has a whine that increases with speed. I pulled the rear cover and removed all fluid with no evidence of metal or any noticeable damage to the ring or pinion gear. I replaced the fluid with 80W90 as listed in the owners manual (I have a 2002, 4.10 non locker). I went by the dealer and their suggestion was to add fluid modifier, which made no change in the noise. I had driven about 300 miles before noticing the noise after installing the pinion seal.

Today I went by a service facility suggest by friend in the industry. His thoughts after a check out drive are that the ring and pinion gear or carrier bearings may be damaged.

My question is…….will the rear end assy out of a 2003 bolt directly into a 2002? I assume the only difference is the drum vs. disk issue. I have located a 4.10 rear out of a 2003 and would like to make the conversion for the disk reason. Just don’t want to get started and run into problems as I use this vehicle for business and only have this week to complete the project.

Thanks for you help........

 

[Todd Z]

IT will bolt in with no issues at all......

The bearings normally make a growling noise not a whine....



A whine would be the ring and pinion back lash being out, or the teeth on the gears are worn a little making the noise....



It probably will be fine, But the rear disc's are nice to have...



ALSO I just noticed you added the friction modifier, You did not need that in a non locker rear end... ALSO the fluid should be the 75w140 synthetic. The owners manual states the 85w90, but it should be the synthetic.....



Todd Z

 

[csamuels]

Thanks Todd.

I didn't add friction modifier at first as it was not listed with a non locker in the owners manual. Also my understanding that synthetic was only necessary if noted on a tag attached to the housing (as it is on my brother-in laws F250).

By changing the rear end out are you suggesting I move to 75w140 on the replacement rear as I am going to install new fluid in the rear end during the change over?

 

[Todd Z]

I would change the fluid in the new rear, yes... I also would look for a limited slip rear if you can, might as well get the benefit of the rear disk and the limited slip...



Most yards do not have the axles in the rear, So you will need to open up the old one and new one to swap the axles...

IF you can get it complete, rotor to rotor, with calipers and stuff, go for it....

Todd Z

 

[csamuels]

Todd,

Luckily (or un-luckily however you choose to perceive it) I am a collision tech by trade and have a great relationship with the salvage yard, so I am getting the complete assy hub to hub.

THANKS for your input so that I feel comfortable about the swap.