Hi guys. First post here. Been lurking a long time and finally registered. I purchased an 03 CVPI last week and I'm confused on the rear diff that's in it. First of all, here is the door sticker:



The axle code "Z5" would indicate a 3.27 open diff. But here is the tag on the housing:



As you can see, it has "L27 exposed, which should be "3L27" or the 3.27 Trac Loc diff. My problem is, I did a little burn out with it and only the right side spun. If I spin the tires in stones though, I get two marks. So do I have the Trac Loc or not? And if I do have it, is it wore out already? The car only has 47,500 miles on it. Thanks for your insights.

One way to test a functioning trac lock is to jack up the rear end, put the car in neutral and spin one tire by hand. If the other one spins in the opposite direction you have an open diff or severely worn trac lock clutches. If the other wheel spins in the same direction you have a trac lock.

Oh and welcome!

I was at the tire place today getting two front tires. When it was up, I spun the right tire and the left spun the opposite way, which is typical of an open diff. The car was in park if it matters or not.

Another point. When I ran the CarFax on it, there was a record of the right axle being replaced. Is it possible when it was replaced they didn't put something back together right? Local Ford dealership did the install, so I would think it was done correctly, but you never know.

hi and welcome to cvn

at this point might as well pull the diff cover and see if you havea posi or not because we can speculate for alot on this.

You will see right away if you have clutches and that wil also tell you that you need to replace them.

good luck

Thanks for the replies. My mechanic, who I also bought the car from, is going to open up the pumpkin cover on Thursday and see whats going on inside. Hopefully, the Trac Lok unit is in it and just needs the clutches replaced.

Also, I have a couple more questions on my car. First, I found this other tag on the diff cover:



This seems to contradict what the manual calls for. I was thinking I read somewhere this had to do with a TSB on the axles. Can anyone confirm that?

Second, I found these paint marks on the cam chain covers:





Are these marks indicating it had the cam chain guides replaced, which I believe was also a TSB? Thanks for your help.

usualy iirc the posi diff will run on 75w140
as forthe x on the valve covers it looks like your timming chains guide has ben replaced

Thanks for the reply. Good to know my timing chain guides have been replaced. Now I just need to sort out the diff.

Well my mechanic looked at the car this morning and he thinks it has an open rear end. He didn't take the cover off, but said he has worked on a bunch of them, and anytime he has had a worn out trac lok, he said the wheels will still spin in the same direction up on the hoist. Or at the very least, if you spin one, the other side will stay still. On my car, if you spin one tire, the other will spin in the opposite direction. So it looks like the door tag was right and the tag on the axle is either wrong, or the police dept that owned the car had the trac lok unit taken out. Either way, looks like I need to start shopping for a trac lok unit. Anybody have any good links to one? And what should I expect to pay for the unit and for installation? Thanks.

it does matter. car will need to be in nuetral for this test.

for all model years the ford 8.8 specifies two different fluids, 80w90 synthetic, or 75w140 Synthetic. factory maintance is 100k drain intervals for 80w90, and 75w140 may be used indefinetly. 75w140 will better protect gears and bearings, 80w90 is better for fuel economy. 75w140 is suggested for severe service or towing, which is why your poice axle may have a tag saying 75w140, or it may have been installed when the dealer performed the axle replacement. factory traction-lock differentials were filled with a 80w90 mineral oil for break in that was to be changed to synthetic at 7500 miles.

early 2003 model year CV's GM's and TC's had axle shafts that had not undergone the hardening process, and because the axles ride directly on the bearings, the axle ride surface quickly became worn, causing noise and bearing failure, which increased wear. there was a TSB and recall repair for certian build dates, but some dates were not covered but still had faulty axles. the dealer has a service kit, which included 2 new axle shafts, bearings and seals, that was to be used to repair the problem.

to install traction lock you'll need a new/used traction lock carrier(if used youll need new clutches too), you'll need to transfer over your old ring and pinon or replace them, good time to change gear ratio. your carrier will need to match your axles, yours are 28-spline, 05.5+ got heavy duty 31-spline shafts. you will need at minimum a R&P install kit, which I would suggest you upgrade to one that includes new carrier and pinon bearings, pinon seal, and maybe wheel bearings and seals. I ran a mineral oil for the first 3k after my rebuild, then switched to synthetic, so you'll likly want an aftermarket diff cover with drain plug for ease of service.

I just got done installing a new differential in my 2003 a few months ago, i had the axle wear isssue that was not covered by the recall, I went and bought an entire 2006 axle assembly with low miles and traction lock, had it sandblasted and powdercoated, had a differential shop rebuild it with the 31-spline shafts and originial carrier, new cobra carbon clutches, SVT heavy duty bearing rebuild kit, and drake cover. then I myself removed my old differential housing and installed the rebuilt one. I have about 1600-1800$ into mine.

you'll want a differential shop to perform the rebuild, its kind of a speciallty job, although your mech or the dealership might be willing to do it you should really have someone the speciallizes in it do it because of all the little things you need to get just right for it to last a long time without issues. most shops in my area want 400$ for rebuild with axle out of the car and 700$ to rebuild it with the axle in the car. and they dont really like to use your parts and I was charged an extra 100 to use my own parts, and parts alone will run you 500-1200 depeneding on what you replace. so if your not prepared to drop 1000 dont bother, you should really do it right when it comes to the diff. you may want to look for a low miles traction lock and just swap it in. good luck.

Thanks for the awesome reply and all the great info. Now I need decide how much money I want to put into it. Or just drive it like it is.

Does anyone have a list of the axle codes for these old cars?
I am looking at buying an old Mercury Colony Park wagon for parts, but if it doesn't have the low rear gears, I am going to pass on it.
Its a 1990 model. Not sure if the codes changed though out the years or not.
Thanks.

Found a used Trac Lok locally on Craigslist. Just rebuilt with carbon clutches. Complete 28 spline unit for $100. I am going to grab it. Then I will start shopping around to see what it's going to cost me to get it installed.