OK. I got multiple questions with my 9.75 3:55 rear end. First my LS clutches started going out. Dint freak out. Stoped by the local dealer and got new 75w 140 synthetic gear lube with a new bottle of the friction modifier stinky crap. As I have heard and the dealer recomended I drained, cleaned and flushed out the rear end. After installing new fluid everything was great for about 2 blocks or untill the secound time I made a sharp turn.. DAM
I gave it about 200 miles before stoping back in to the dealer. They recomended one more thing. Adding a second bottle of the friction modifyer.
So I dumped that in. 50 miles later not only is the rear end still chattering every time I turn (as if thats not annyoning enough) now it has developed a sort of a hum or howl sound. I hate trying to describe sounds lol. Best I can say is it sounds like im running 35" tires. Doesnt matter if im going 15mph or 70. Same sound remains constant.
Doing a search looking for threads on preforming the clutch replacment I read that a rear end howl while rolling indicated a posible pionion bearing issue?
I should add that the truck has less then 60k on it.

So is it possible that using to much of the FM caused dammage to my bearings??
If not then what the heck caused the tire hum noise all of a sudden? Perhaps this is common once the cluches fail?

If the pinion bearing is going out, will I be able to tell by unbolting the drive shaft and giving the pinion yoke a stern wiggle?

I ask because I got the clutch pack kit today (thrilled to see that it came with directions and shims!) and I dont want to take the time and $$ to open it up again, replace the clutches and still have the noise issue.

I got more ?'s but this stuff needs resloved before I travel those paths..

Thanks for any assistance!

 

After opening up the diff.. first thing i noticed was a 1 inch tall film of a white yellowish foam accross everthing at the oil fill level. I dont recall seeing any foam last time i took the cover off just a few weeks agao.
This was brand new oil. What the heck went wrong?
Wish i could figure out how to post the pic i took of the foam.

What product should i use to clean/flush out everthing before i replace the clutches??

last time i used brake cleaner and i wonder if that i what caused this mistory foam?

Pinion bearing feels rock solid from the gear side and drive shaft side. Theres nothing wrong there.

 

I just found this .... where you at on the repair now?

I wouldn't think that the friction modifier would hurt the lube. As long as you had enough lube of the corect type, the modifier is compatible ..... I doubt that hurt anything.

 

Well it has been quite a strugle as this is the first time I have ever pulled a carrier out. Thuss why I have been asking so many questions.
I dont have any of the speciatly Ford tools. So I made my own tool out of all-thread to compress the clutches for spider gear removal.
This is where the probems start! I had no idea that you had to "roll" the spider gears out. I thought you had to compress the clutches to the point that the spiders would just fall out. WRONG!
I ended up stripping out my piece of 3/4" all-thread and had to cut it out of the carrier with a saw-zall. Frustration set it at that point and I had to take a break.
I ended up calling around and found a buddy that knows a guy that works at the ford dealership. LUCKY me he was able to barrow the tools for me to dissassemble the carrrier. (on a one time only deal)

As of today everthing is dissassembled and cleaned on my bench. I have the new clutch sets. I did not like the looks of one of my clutch spring beveld washer. It looked flatter then the other. So I ordered new ones just to be safe. Purhaps I damaged them when I was crushing the shi$ out of everthing with my all-thread.. ups.
The new spring washers are due in today when I get off work.
Now the question is:
1. How do I no what size shim to use with the new clutches without the
ford tool?
2. How do I roll the spiders back in once I have the clutches back in the carrier.

I no I can compress them with all-thread, but I need somthing to hold one gear in place while I try to spin the carrier to roll in the spiders.
Could I set the carrier on an axle and hold the axle in my bech vice or maybe a strap wrench??


I can not be the first to replace clutch packs in a 9.75 without using the ford tools. So im certain others no what to do here.

Thoughts?
thanks.

 

I hope you took backlash measurements BEFORE you took the carrier out. If not it's possible that the whole rear end might have to be completely set up again. Lesson to learn here...if you are not sure how to do something..DON'T DO IT !!!

 

Why would I have needed to take a backlass measurement? I have not really "upset" anything. Never touched the pinion gear and both the ring gear and carrier bearing have not been removed. All that stuff is staying put.
If you dont know how to do somthing, how are you suppose to learn????
I suppose I just could have pitched 500-800 bucks at the Ford garage.
Or I could figure it out myself. Hell even if I have to do the hole job twice I am still money ahead and a better man for it..

FYI: "all thread" or "ready rod" is fully threaded rod you can normaly purchase at a home center or hardware store by the foot.

 

Threaded rod is what that is usually called..I know that.....The backlash needs to be measured before the carrier is removed so that it can be re-installed with the same measurements, otherwise you could get a different wear pattern on the ring and pinion and have a worse noise than you have now. The best thing to do on a project is to read and read some more before diving in and creating a nightmare which could cost you more in the end.

 

I agree about doing the reasearch first. The fact is I ran out of time. The LS had been slipping and chattering for about 3 months. I had been doing reasearch on and off for the same amount of time. When the tire hum noise started it was the straw the broke the camel's back. I could not take it anymore. I had to dig into it as I did not know if I had bigger problems going on in there (like a broken spider gear or somethting). I was and still am pretty frustrated on the amount of info I could find on the web and this site reguarding the clutch pack replacment for a 9.75. I was really crossing my fingers that someone would do a "how to thread" before I did mine.
I managed to change my spark plugs (twice) using some info and knowhow from this site. Start to finish less then 2.5 hours (none broke off)! I have been hooked ever since. Im no stranger to mechanical work, growing up racing dirt bikes, then moving to the drag strip on sportbikes. Now I seem to have a thing for 4x4 trucks and ATV's.

Now im just babbling..

Reguarding the pinion. Since I have not moved the pinion, pinion bearing, crush sleave, ring gear or carrier bearings evething should bolt back in the exact same way it came out. I will install the same carrier bearing shims on the same sides the origianly came out of. Both the ring gear and pinion gear look perfect. And should with 54k on the truck. Pinion bearing and carrier bearings seem better then solid as well. So I am still puzzled about the noise. I am hoping it was just from whatever was contaminating my oil and causing the white yellowish foam.
Infact the reason I choose to replace the clutch packs vs installing a tru-trac is because changing the clutches does not require reseting the backlash.
Or so I was told by someone on this site in anther thread (crossing fingers that they no what ther talking about!)

There is 2 kinds of people. Those that figure things out, and those that pay others to figure things out for them...
There is also those that can spell and type. lol not my best skills

 

For anyone interested or concerned.
After the kids and wife whent to bed last night, I decided I better get this thing back together. Dont want to be wrenching on it this weekend when I could be out wheelin on my quad.
Using a caliper I took a bunch of measurments on the old clutch plates and the old shims used. I find that the new clutch plates are the same thickness as the old ones. I checked 3 of each to insure they were consistant. The shims that pulled out were .075 on each side. I wanted to shim it a bit on the tight side. When installing the new clutches and new spings (beveled washer) I went with the .080 shims on both sides.
I have read about 4x4 guys and hot roders changing up the shim and plate order for better grip? I figure it was best to stick with the OEM configuration and I installed as the directions specified witch was also the same as the old clutches I removed. DONT FORGET TO SOAK THE CLUTCH PLATES IN FRICTION MODIFIER FOR AT LEAST 15 MIN before installing them. This was stressed in the directions and I am sure its an important step you dont want to skip to ensure long life of the clutch plates.
I was able to roll the spider gears back in using a peice of threaded rod and some nuts to compress the clutches. I had to use an axle in my bench vice to hold the carrier while I rotated it with a breaker bar with a cheater on it.
That step is probably a 2 person job. I managed to strugle along. Would have been way quicker to have a buddy handy. I dont recomemd putting a axle in the bench vice but it was the only solution I could come up with. Vice jaws bearly mared it much. I cleaned it right back up with some emry cloth. The rest is a cinch. Put the carrier back in place. Checked the gear mesh wear with some gear compond. As I suspected it was good to go! Good idea to put new axle seals in before installing the axles. so I did. Got every thing done exept fillin her up with 5.5 pints of fluid and FM. I use the OEM fluid.
I dindnt feel like getting that crap on me and it was getting late. Took me about 2.5 hours to reassmeble everything by myself.
After work today I will install fluid and take a test drive.

 

WOW I forgot how smooth the truck used to turn! She corners like a dream again. I only took about a 5 mile test drive mostly in town driving. Had to run accross (small) town and pick up my kids from the sitter. Kids were in a good mood so we did a small cruise. Ran her up to highway speeds 60-70. Every thing seems good and smooth. Definatly fixed the shimmy and shaking that was going on durning low speed sharp cornering. I did not pick up or hear and noise coming from the rear end. I did have the radio off but 2 young boys are never totally quite.
So its all good for now!
I can do a follow up post if anyone wishes after a few tanks of gas?

Total investment:
OEM clutch kit 9L3Z4947C 76.62
OEM rear axle seals 24.10 (for both)
OEM gear lube 66.09 (for 3 quarts)
OEM friction modifier 6.23
OEM clutch springs or I call them beveled washers 63.60 (for both)
Add in tax and a few bucks for shop supplys and I total about $260

Not bad. I feel really good about the repair as it was the first time I have ever played with a diff. Think I had about 7 hours total in the job, but I had a lot of problems and head aches barrowing and making special tooling for the job as I went along. If I needed to do it on a buddies truck now that I have a clue whats intailed it would take somthing close to 1/2 the time..

 

^^ Sounds like a good job, Well Done !!!

 

Thanks!
My intent it to provide some information to anyone looking to replace there clutch packs. I think accomplished that.
I am not staying preforming the repairs without the ford tools it the best idea but it can certainly be done.
I took a few pic's with my phone as I was going along. So if anybody needed some visual aid on what to do I could help.
I still need to learn how to post a pic in a thread. It seems more complicated then the clutch replacment. LOL

And how the hell do you get the gear lube smell out of the garage?! I scrubbed the floor with 2 bottles of pine-sol. It still smells so bad in there that my wife wont park her car in there.
More room for me I suppose....

Again I hope this helps anyone considering replacing there LS Clutches themselves.

 

Great write up .... and your thinking was right as long as you used the same ring gear, carrier, and shims in the same housing and have not mixed up the two caps.

However, the deal about measuruing back lash before dissasymbly is required if you hope to put it back the same with a rear end that uses those large threaded cups outside the carrier's bearings to adjust backlash. The 9.75 as you know, uses shims.

 

Thanks man.

 

Hey 04Supercrew 150,

I am looking for someone to help me with the same rebuild on my 05 supercrew. Would you be interested in helping another member out. I live near the quadcities.

Thanks

Chris