Some general 8.8 questions

[KNanthrup]

Hi guys, ive been doing a little searching here on the forums but I haven't found anything to quite answer my questions yet. Maybe some of you can help.

I just picked up an 8.8 rear out of a 1st gen explorer. I'm not sure on the exact year but it has drum brakes. Now, I'm wondering if there's an easy way to tell the gear ratio. Is there a marking on the axle itself outside? If not, is there a number for tooth count on the ring gear or somewhere inside? I just don't want to have to be counting teeth here.

Also, I've heard this rear is pretty stout. Anyone know how much power the stock assembly w/ stock posi can handle? We're talking drag racing use here so assume fairly sticky traction.

Thanks guys, id appreciate any help you can offer!

 

[section525]

Usually there's a plate bolted onto one of the cover bolts. It'll say 373 on it or so. Or you can just turn the pinion and count how many turns until the wheel would go around once.

You can also get a kit from Ford to swap this over to disc for pretty cheap I believe.

 

[Eneurb]

The gear ratio is also stamped on the pinion gear, but you need to have it apart to see it.

 

[KNanthrup]

Thanks for the reply guys. I have another quesiton though, does this rear w/ posi require a different type of lube or is it just standard gear oil? Thanks

oh and also if anyone knows about the power handling of this rear.

 

[dman726749]

need a friction modifyer with the l/s, its like 3 bucks a bottle....as for power, its got 31 spline shafts, so i am sure it can handle plenty of power, but i wouldnt trust the factory l/s for much, they tend to wear out around 40k miles on normal street driving and if you are going to be launching hard on it repeadetly i dont see it holding long and you will be into one wheel peel then, and we all know that one wheel peel is ghey. i would get a powertrax or other lunchbox locker or even a full detroit if this is going to be a serious strip car.

 

[techieman33]

Ya, the one wheel is pretty ghey, I still do it though. I just have to keep better track of my tires so they wear evenly. It's still fun to put up a big cloud every now and then though.

 

[KNanthrup]

Well I guess I will probably pop the diff case to check things out inside. I didn't know the L/S's wore so fast, im assuming the obvious that its a clutch style. Hopefully the truck i got it out of wasn't used much

 

[greenbeer]

My 93's 8.8 has 193K on the L/S, and it works great.

 

[dman726749]

yep its a clutch pack style l/s, rebuild kits can be bought from ford for like 40 bucks or they are on ebay for that much alot of the time too

 

[prozachappy]

My question is if you just picked it up...and don't know the axle code/ ratio, then how do you even know if it is LS ??? Not all 8.8's have the limited slip, infact... many of the 1st gens are open diff. There should be a metal tab connected to one of the cover bolts with the axle code on it. If thats not there, then like said above spin the pinion and count how many rotations it takes for the wheel to make one full turn..this will give you your gear ratio. But if the tabs not on the diff cover, you'll need to open it up to see if it is LS or open diff.

 

[KNanthrup]

My question is if you just picked it up...and don't know the axle code/ ratio, then how do you even know if it is LS ??? Not all 8.8's have the limited slip, infact... many of the 1st gens are open diff. There should be a metal tab connected to one of the cover bolts with the axle code on it. If thats not there, then like said above spin the pinion and count how many rotations it takes for the wheel to make one full turn..this will give you your gear ratio. But if the tabs not on the diff cover, you'll need to open it up to see if it is LS or open diff.

The guy at the junkyard told me he checked it. Don't know if that means he read a code or if he turned the axle to see if they locked together. As far as the tab on the diff cover, is this going to be a code I need to decipher or will it actually say limited slip on it? If there is a code, can someone tell me what it is or what I need to look for on the tab?

Once again, thanks for the replies guys.

 

[KNanthrup]

Oh and this is the same carrier as the Mustang 8.8 right? It's nice to see there are lots of parts readily available for it at cheap prices. I see some posi carrier units on ebay selling for $30-60, and rebuild kits for cheap too. I guess if for some reason mine turns out to be an open diff I could just grab a posi carrier for cheap.

 

[dman726749]

most mustang 8.8's are 28 spline axle shafts, explorers use the stronger 31 spline shafts, so carriers and lockers will not be swapable bewteen the two...i think cobras had the 31 spline shafts too, and there is plent of parts out there for these axles

 

[prozachappy]

So the junkyard guy told you it was LS but didn't tell you the gear ratio??? Sounds fishy to me!!! You need to verify what you have, how much did you pay for the axle ? If its not an LS its not worth more than a $100 or so. I got a 4:10 LS out of a 97 for $200 w/ discs, hope you didn't pay much more than this. Did you pull it from the vehicle or was it pulled already? If he told you it was LS, then he either read the diff cover tag or the door code from the donor. Check the tag on the cover, should have a series of numbers ending with one of the following codes...

Axle Codes
Code Description Capacity Ratio
41 Open 3200 3.27
42 Open 4.10
43 Open 3200 3.08
46 Open 3.73
45 Open 3.55
D4 Limited Slip 3200 3.73
D2 Limited Slip 4.10
L73 Limted Slip 3.73

 

[KNanthrup]

So the junkyard guy told you it was LS but didn't tell you the gear ratio??? Sounds fishy to me!!! You need to verify what you have, how much did you pay for the axle ? If its not an LS its not worth more than a $100 or so. I got a 4:10 LS out of a 97 for $200 w/ discs, hope you didn't pay much more than this. Did you pull it from the vehicle or was it pulled already? If he told you it was LS, then he either read the diff cover tag or the door code from the donor. Check the tag on the cover, should have a series of numbers ending with one of the following codes...

Axle Codes
Code Description Capacity Ratio
41 Open 3200 3.27
42 Open 4.10
43 Open 3200 3.08
46 Open 3.73
45 Open 3.55
D4 Limited Slip 3200 3.73
D2 Limited Slip 4.10
L73 Limted Slip 3.73

Well I've actually seen it. The axle is still in the truck, but the truck has its tires off and is sitting on some tires on the ground so i can't really get under it. I went back today to see if I could read the tag. It was hard but this is what I got from it, not 100% positive in accuracy from my view but I think I got it.

7 8 8 81M09
S6298

That's what seemed to be on a tag on the passenger side of the diff. From that code I don't see any match to decipher what it means. All I know is it's from a pre-95 with drum brakes and the 4.0 at this point. Paid $175 for the whole unit.

 

[X-1]

look for the axle code on inside of drivers door on donor vwhicle, you are missing some numbers, chances are 3.27 open carrier, from the 7 across, at the 8's there should have been a raised dot meaning 8.8, the rest of numbers not sure about.

 

[Espresso]

Lower left side of the tag should say something like 3L27 or 3 27( nothing in the space where the L would be).

Remember just because it says something on the drivers side door doesnt mean that is what is in the vehicle. They could have done a swap themselves. Never know.
The best way to tell is to do the pinon turn & count.

 

[KNanthrup]

Thanks guys. I'll have to see if I can check the tag again from a better angle or maybe check the drivers door. I turned the axle on each side and it also makes the other side turn in the same direction.. does this mean anything? It's not frozen together either because i jammed a stick in the lugs and it stopped the other axle but could still tell it had force on the wheel. It doesn't seem to me that an open carrier would do this? typically they dont spin at all or spin backwards

 

[KNanthrup]

Woohoo! Alright guys, I picked it up today and checked the tag. It says 3L73 (mistook the 78, was actually 73), so it is a posi 3:73!!! That's exactly what I wanted too, definitely happy about that. He gave me the whole rear including all brake lines and sway bar and everything attached plus the driveline so I can modify my current driveshaft with the disc type connection for $175. Not a damn bad deal if you ask me. I think im going to pop the diff and check things out, repaint the whole thing and get it fresh fluid. Thanks for your help guys

 

[KNanthrup]

Oh, one last quick question. What's the electric plug connection for on the top of the diff? When I popped the rear cover it looks like there's another thing ring gear on the side with teeth that rotate by it. Some sort of sensor?