03 IRS: Speed sensitive 'clunking'

[03SVTCOBRA10TH]

Ok, that makes sense about the pic posting, I must be getting old, I seem to know less and less about computers each day. LOL!!

The pinion preload most likely will not affect anything other than make the initial turn of the pinion gear more difficult. It is such a small amount of torque it is more like a drag force of rotation, Unless the pinion nut was may loose then you can move the pinion shaft/gear in and out by hand, and that will make some noise.

FYI, I added a link to another site in my above post with a pic and measurement discription as well of what I was tying to explain in reguards to the pinion head measurments..

 

[Booksix]

hahaha, yeah, I hear you. I work with computers and new tech. all day long (audio production) and I too feel like I'm falling behind in the computer world!

Makes sense on the preload. I was just thinking maybe it was loose but I should have realized that I'd most likely be able to feel that at the companion flange.

As far as measuring the pinion, that is actually what I was referring to in my last post about where to measure (the geared portion). I guess neither of our descriptions worked very well for the other! But thanks for the link. I'll try to get this thing tore down tonight after work and I'll post that measurement. :thumbsup:

 

[03SVTCOBRA10TH]

No prob. Your gonna love the IRS once you get everything set up right!!!

 

[Booksix]

yeah, I really hope so! Sounds like a good performer and will balance the car out a little more. I can't wait!!

Another issue, do you know where I can get a bearing seperator? I wonder if autozone has them in there list of loaner tools...? And yes, I have a press

 

[03SVTCOBRA10TH]

Nice, it worked!!!! Thanks!!

Measure this distance in red, and subtract from 4.420" to get the pinion depth. Then compair it to the number stamped on the top of the pinion gear and add the needed shims to equal the number on the pinion head. If you have no number stamped on the pinion head, you will have to get a pinion depth tool or use the gear marking compound method.

 

[Booksix]

Looks like I need to call Ratech tomorrow and upgrade my order to a kit with carrier shims. I pulled the carrier and there is just one shim on the outside of each bearing (these are the shims, right?):

edit: on second thought, if there are cast, solid shims in place I'd have to think they were the stock pieces...? So now, if the stock shims and a set of original ford 3.55's (not necessarily the ones that came in the rear end but at set from an 03 IRS for sure) perhaps I didn't get an accurate backlash reading (it was very hard to get the ring gear to move without the entire center section twisting around on the floor)...? Plus, if I have to increase my pinion depth, won't this increase backlash as well? This could potentially bring my backlash into the .008-.015 range without changing shims at all. Thoughts?

Also, I got my Carbon disc clutch kit and some energy suspension spring isolators ordered. Should have a perfect ride height once these are installed! I had to make new upper spring perches out of 1/4" steel plate and 5" thick wall pipe to be able to run the h&r springs that came with the rear end but they are a little to low without isolators (which I want anyway). Hopefully I'll be getting MM coil overs before long as well. Coming along... i need to rent a fender roller from ebay as the last step

 

[Booksix]

Ok, so I have my order on hold at Ratech. What is the thought here? Will pushing the pinion deeper raise my backlash from .004" into spec using the stock, cast shims or should I upgrade my kit to include carrier shims?

 

[03SVTCOBRA10TH]

Sorry, I haven't gotten to this sooner, I have been sick.

Anyway, I would hold off on the carrier shims for now. You have the master shims there from FORD, thoses are the originals. I would set up the pinion depth and then recheck backlash. Clean off the ring gear and pinon and see if they are FORD or another company. If they are FORD then you might get lucky and you also need to mic each shim there and see which is bigger, as they might need to be swapped to the other side. Resetting the pinion depth and or swapping sides with those shims might correct everything.

 

[Booksix]

bummer man, hope you feel better! And no sweat on the timeline. I appreciate the help, even if it does take some time for you to get back on here!

I think they are Ford gears. three reasons: no pinion depth markings, the pinion has a Ford like part number stamped on it (which includes the numbers 355) and the seller told me he would put the 3.55's back in - sounded like he meant the originals. Based on that and what I've read about different gears and markings I'm guessing they are Ford.

So, the shim I pulled off the pinion appears to be a .030" shim. Based on the wear pattern I posted, what size shim should try first? .020"? .015"?

Also, I got ahead of myself last night and tore everything out so I'll never know what the pinion bearing preload was at and if it was contributing to the problem but either way my torque wrench should show up soon so I'll be able to reassemble everything properly!

 

[03SVTCOBRA10TH]

After another look at your pics they look like FORD gears. I would try the 0.020 shim first.

Can you get a thickness on the carrier shims?? You will most likely need to put the thicker one on the right side to correct you backlash.

When you tear down the diff, make sure to get all the gear oil off, use brake cleaner if you don't have a parts washer. You might have to put the diff in a vice and use a propane torch for a few secs where the ring gear mates to the diff at the spot where each bolt is, if the installer used a lot of red locktite.

Once you have the ring gear off, remove the retaining bolt that holds the shaft in place. Then remove the shaft. Then you will need to remove the S-spring, take a pic of its orientation, then use a long socket and a hammer and tap it out slowly, I cover it witha rag so it dosen't fly away.

Then rotate the larger drive gears, that will rotate the spidergears and thier bearing races. Then remove the drive gears. Pull off the old cluthces and steel plates. Then replace the cluthces and steels in the order they come in the kit.

If you want to use the alternate method you wil need to save the 2 best clutches from the diff and remove one steel plate from the new kit. The alternate stacking order is 0.030 shim, C,S,C,S,C,S,C side gear, diff, side gear, C,S,C,S,C,S,C, 0.030 shim.

Then put the drive gears back in and then line up the spider gears and thier bearing races and you should be able to rotate the drive gears so the spider gears go back into place. And if you did it correctly, they will line up with the holes for the shaft.

Then you need to pull out the pic and orient the S-spring, put the edge of it in the space it goes, then use the 2x4 to hammer it in (this is the complicated part untill you have done it a few times, you may need to call me so I can walk you through it a little better). Then put the shaft in and the retaining bolt. The the ring gear and bolts and then you are ready to check/ set backlash.

 

[Booksix]

Ok, .020" shim it is. And yes, I can measure the carrier shims and will put the larger on the right side.

As for the clutch packs, I've been debating which method to use. This a street car that will very rarely make passes at the strip (probably not even once a year) and I don't plan on doing any crazy street launches or anything like that. Also, the 5.0 in there will remain under 300 hp for a few years yet so I'm really leaning toward the factory stacking order....

And last, have you ever tried the hose clamp method of putting the s-spring in? A lot of what I read says it's the easiest way but obviously idk as I haven't done it yet.

 

[03SVTCOBRA10TH]

Ok, if those are the plans for your car then use the stock, pre-stacked clutch order and you will be just fine. I do the alternate method for 1000hp+ monsters, I forgot that your car was not a crazy high HP Cobra.

As far as the S-spring, I have tried the c-claps, worm gear clamps, vice grip, and brute force methods and none work worth a damn compaired to a 12 in 2x4 and a hammer, one tap and it is in. Let me see if I can post some pics. I have to go over to the shop today anyway to shippout something for another client, check back here for more details.

Also, post up some pics of the clutches when you tear it down... I bet they are shot!!

 

[Booksix]

yeah, those are the current plans, although it will see a twin turbo kit in a couple years but I think I'm going to go back to school before building... So I'll roll with the regular stack

And yes, I'll post pics of the clutches! . And thanks for the tip on the s-spring, I'll try your method first!

 

[Booksix]

Another question: is there a specific reason why you recommend removing the ring gear? It seems the clutches can be accessed with it in place... is it easier with the ring gear off?

 

[03SVTCOBRA10TH]

I always remove the ring gear, as I like to inspect it. Also, it make the assembly lighter when working with it. Also, I know that when I reinstall it, it has red locktite on the bolts and they will not back out. Lastly, you will need to remove it to get the clutches and smaller gears out.

 

[Booksix]

Got the clutches out. It may be hard to see in the pic, but all the high spots where carbon strands meet in the weave are worn down. Each little cross in the carbon fiber is worn down in the shape of a little circle. Other than that, they look way better than I was expecting (I'd never seen shot clutches before, I expected ALL the carbon fiber to be mostly gone, not just the high spots):

 

[03SVTCOBRA10TH]

Yeah, thoses are shot. If it was race day, I would just shim the heck out of it and run, but those have seen better days.

Run your finger over them and then compair to the new ones. The new ones will also swell up some when you soak then in friction modifier.

I got a spare diff from the shop yesterday, I will mock it up and take some pics to show you how to get the S-spring in ,or you will be going crazy over it.

Also, FORD recommends soaking the new clutches in friction modifier before installing them. I don't use friction modifier in mine, then again you will never hear them over the exhaust. I also run 80-90 gear oil instead of the 74-125 synthetic gear oil FORD uses. It is really up to you. Try it the stock FORD way for normal street use.

 

[Booksix]

I actually got the s-spring in :banana: but the pic may help others so go ahead and post it up!!

Ok, so I'm starting to feel like I'm a spoon fed child but, do you have any tips on holding the diff while torquing the ring gear bolts?

 

[03SVTCOBRA10TH]

I put it in a 5 inch vice and torque to specs.

You can use the impact gun, then you could have a buddy hold the oppisite side bolt with a breaker bar or long handle socket while you torque the bolt across, just don't damage the bearings or races on the carrier. Don't forget the red locktite.

 

[03SVTCOBRA10TH]

Any updates??? Hope it is going well!!