post 8.8 swap questions

[joef753]

I have an 8.8 out of a 96 tranplanted into a Jeep Cherokee (but I heard y'all werent hostile to that). There's a few things that I hope you could clear up.

The diff fill plug is brass and has two wires leading from it. When removed, the resistance changes when heat is applied. Is this an aftermaket temperature indicator - or related to the ABS system?

What is the recommend weight and quantity of gear oil? I was guessing 75 or 85w140 synthetic.

What do you think about the bearing caps and aftermarket diff covers?

What about carrying spare axleshafts - how often does breakage occur? Any unusual tools required to change a shaft trailside?

Thanks for your assistance

 

[Ray Lobato]

Hi Joe and welcome to the site.
I can't help you with what that resister thing is , but All the manual says is to fill it up until it starts leaking back out of the fill hole. They recommend hypoid gear lubricant SAE 80 or 90.
Now so far I haven't heard of anyone breaking an axle yet, and some of these guys go some pretty rough places, Example, Rubicon, and seeing as that our Explorers weight alot more than your Cherokee, I don't really think you will have a problem with breakage. The only thing stronger than an 8.8 is the 9 and the Ford 9 isn't too much stronger. Like anything, it can be broken, but you'd really have try hard to do it.
Oh almost forgot. I would recommend putting a good axle cover on. One that supports the carrier as when the axle starts to flex it can cause the spider gear to also either flex or break. Many of us with lockers have these and it does seem to help hold everything together better.
Last year at Moab a few of the guy ended p blowing their lockers, but the guys with the heavy duty covers seemed to fair much better. I have a Granatelli rear diff cover/support myself to help keep my ARB locker safe. One of the other Jeepers on here was saying that you couldn't put one on a CJ but maybe you could do it on your cherokee. Do a search in the modified or suspension forums for Ford 8.8. There are other jeepers that ask this question all the time.
Hope this helps.

 

[Robert]

It depends on what his axle ratio is and what engine he has. When in the Explorer, the 8.8 calls for 140W synthetic when the Explorer has either a V8, limited slip or 4.10 ratio. Otherwise, it gets the standard 85W gear oil.

 

[LukeDog3D]

The thing with the two wires leading from it is the abs sensor. The fill plug is located below the abs sensor. You can still fill it up from the hole where the abs sensor goes, but if you shoot oil in there until it is topped off at that hole, it will be overfilled. Fill it up thru the fill plug...take it off with a 3/8" ratchet extension. Oh yea...that 75W-140 synthetic Motorcraft oil is like 18 bucks a quart!! Dont forget the 2 bottles of friction modifier if you have a trac loc. I think it takes about 3 1/2 quarts to fill up.