8.8 rebuild

[SMOKEDYA]

Going to rebuild the possi in my 8.8.As long as i keep the shims on the correct side when i take it out and then reinstall them in the same spot,i should be ok correct?Also whats the ticket to making the possi tighter?I had my old one done at a shop and if i remember correctly they installed more of one disc type then the other to make it tighter and grip better.Just dont remember the correct process and what more of a certian disc or how many they used.What do you guys do???peace








john

 

[rockyracoon]

Well it all depends. If you're. Just gonna rebuild the posi unit, technically you should be able to get away with reinstalling the same pinion and carrier shims and hit the ground running .now if you are swapping out the gears with non ford gears the rear will have to be set up measuring pinion depth and backlash however it is rumored if you go with ford gears you can get away with the same pinion shim and possibly the same carrier shims but if the existing shims are the factory cast shims it may be hard to get em in without cracking them unless you have a case spreader. Of course this is just my opinion based on having spent countless hours setting up a number of 8.8s over the years. IMHO the hardest thing is determining the proper pinion shim without the factory rotunda pinion depth tool and it is also a beeotch to crush the sleeve.

 

[rockyracoon]

Oh yeah some guys do install an extra clutch in the posi unit.

 

[rd]

The carrier shims are unaffected by this. Put them back the same way you took them out.

There are shims at each side, between the side gears and the case that tighten/set the left-right play in the traction lock unit and clutches. Adding another clutch would most likely mean using thinner side shims there. The Ford rebuild kit, iirc, comes with a selection of these shims.

 

[NIKwoaC]

IIRC, in a stock Traction Lok, the "clutch pack" on either side of the spider gears uses only 3 friction discs. It's setup something like steel-friction-steel-steel-friction-steel-friction-shim (SFSSFSFS). To get more out of it, you want to run 4 frictions per side, so something like (FSFSFSFS). In other words, alternate each one friction/steel, don't double up the steel discs.

 

[SMOKEDYA]

Well it all depends. If you're. Just gonna rebuild the posi unit, technically you should be able to get away with reinstalling the same pinion and carrier shims and hit the ground running .now if you are swapping out the gears with non ford gears the rear will have to be set up measuring pinion depth and backlash however it is rumored if you go with ford gears you can get away with the same pinion shim and possibly the same carrier shims but if the existing shims are the factory cast shims it may be hard to get em in without cracking them unless you have a case spreader. Of course this is just my opinion based on having spent countless hours setting up a number of 8.8s over the years. IMHO the hardest thing is determining the proper pinion shim without the factory rotunda pinion depth tool and it is also a beeotch to crush the sleeve.

Thanks for your input,but i think you missunderstood me.

The carrier shims are unaffected by this. Put them back the same way you took them out.

There are shims at each side, between the side gears and the case that tighten/set the left-right play in the traction lock unit and clutches. Adding another clutch would most likely mean using thinner side shims there. The Ford rebuild kit, iirc, comes with a selection of these shims.

Thanks.So are you saying i will need to reset the backlash and so forth once i install extra discs?

IIRC, in a stock Traction Lok, the "clutch pack" on either side of the spider gears uses only 3 friction discs. It's setup something like steel-friction-steel-steel-friction-steel-friction-shim (SFSSFSFS). To get more out of it, you want to run 4 frictions per side, so something like (FSFSFSFS). In other words, alternate each one friction/steel, don't double up the steel discs.

Thanks nik peace






john

 

[LXstangLX]

I just rebuilt mine with the kit that comes in the Cobra.. it has carbon discs instead of the other material and the "S" clip is considerably stiffer. I will say its pretty tight with just the 3 fiber set up in the Cobra kit and that "S" spring will hurt you if it gets away! I took mine to Powered by Ford and had them install the spring and the tech there said about 400lbs of pressure to get it squeezed down enough.
To answer your question about the shims.. I am in the same boat as you.. my carrier had no shims just the factory thicker spacers on both sides. Also, my pinion... ZERO shims... stock 3.08s are coming out and 4.10s going in... has anyone else ever seen this "no shim" method? I havent put it back together as I just need to research whats going on here before slapping what could be a very expensive rear end rebuild back together.
Dont mean to thread jack but I do have a very similar problem.

 

[94GTCoupe]

Can't remember the extra fiber arrangement off the top of my head.
I'm sure it'll pop up in a Google search.

Keep the carrier shims on sides they came out of.
They'll be a little tight reinstalling them.
You'll need to tap them in.
Be careful though,they like to crack.

For the s spring,2 needle nose vise grips,a punch and hammer.
Compress the spring with the vise grips,use the punch and hammer to tap it in.
Works every time,I've done it on both the standard clutch packs and carbon fiber cobra pack.

 

[LXstangLX]

I guess I was more worried about the S spring than I should have.. i thought to use the vise grips but thought the teeth would mess it up so I went the C clamp route.. just couldnt get that big combo close enough to hit it in the lok assembly. Good on you for doing it yourself davis3.. I just didnt want to lose an eye! lol

 

[rockyracoon]

I just rebuilt mine with the kit that comes in the Cobra.. it has carbon discs instead of the other material and the "S" clip is considerably stiffer. I will say its pretty tight with just the 3 fiber set up in the Cobra kit and that "S" spring will hurt you if it gets away! I took mine to Powered by Ford and had them install the spring and the tech there said about 400lbs of pressure to get it squeezed down enough.
To answer your question about the shims.. I am in the same boat as you.. my carrier had no shims just the factory thicker spacers on both sides. Also, my pinion... ZERO shims... stock 3.08s are coming out and 4.10s going in... has anyone else ever seen this "no shim" method? I havent put it back together as I just need to research whats going on here before slapping what could be a very expensive rear end rebuild back together.
Dont mean to thread jack but I do have a very similar problem.

the spacers are the shims. if you check the thickness im sure youll see that they are not equal. I guess in theory no pinion shim could be required. if youre going with ford gears just put everything back exactly how it was. but you would do well to at least check your backlash and make sure it is within specs. for that youll use a dial indicator on a magnetic base. and you will also need an inch pound torque wrench for the pinion bearing preload.

 

[FoMoCo17]

I installed the Cobra carbon fiber clutches in my 8.8. The Spring is larger but looked deformed when installed which was key for me ... called Ford Racing and they recommended getting a new S-spring for my application. So, though they may fit, I do not believe the newer-larger S-springs are applicable to the old 8.8 since they do not look correct once installed ... they may work but the question would be is it correct for the application. It is known that the carbon fiber clutches are dimensionally the same just an improvement in friction characteristics for the 8.8. Just installing a severely distorted larger spring didn't make sense to me.

As far as pinion shims, general rule is to install what you took out and check it and make any modifications up or down. Mine was .024" and had to go to .030" with a Ford Racing Gearset.

As far as carrier shims, one of my cast shims had rocking marks in it on one side as set up by Ford. Based on this, i knew I needed to add more shims. Stated out with what was in there, made my checks and adjusted them appropriately. Then after I knew what I needed to have a friction fit with light hammer taps, I added .004" ( I think ... can be googled) to each side then put shims/carrier in as an assembly and tapped in in equally with a dead-blow plastic hammer to preload it properly w/o a spreader. Haven't had any problems so far. Search google cuz there are a few good write-ups on this. Do it right the first time and you shall smile when everything works correctly. Its not hard just time consuming to check and re-check ... but once you know what ur doing, u shall be very confident about what you are doing!