Rear End Dissasembly Help
 

Hey guys, while the car is up for the winter here in Illinois..... sniff, sniff, I have decided to stop the oil drip out of the rear differential. I have the drive shaft off and the wheels off. The rear has a small drip coming from the front cover and I can see RTV that has not done its job fully evidently.

The Heim bracket hooks on the top 2 bolts and I have found those to be loose before, so I will replace all of the cover nuts with new locking nuts when I am done.

My question is when all of the cover nuts are loose do I have to pull the axles to take the front shaft and cover off to reseal everything for re-assembly?

If so how do you get the disk off to get to the 4 bolt heads to pull out the axles? Still in the learning curve here. Hope these pictures help.
Thanks Guys
Kirk
http://www.realtree.com/img/614/medium/diff1.JPG
http://www.realtree.com/img/614/medium/diff3.JPG
http://www.realtree.com/img/614/medium/diff2.JPG

Looking at the bottom picture the rotor is probably only stuck on with a little rust around the axle flange. Give the rotor a few hits with a large hammer, between the studs where the wheel sits (not on the brake pad surface). It should pop off. You do have to remove the axles and then the center section (pumpkin) will come out.

Thank you very much! I did not want to start hammering before I knew for sure.

Much appreciated
Kirk

Under the rotor, there should be a hole in the axle flange large enough to pass a socket through to remove the four nuts that fasten the axle retainers to the axle housing. Remove the nuts and the axle will pull out. You might need the help of a slide hammer.

Also, when I installed the third member into my axle housing, I used copper washers under the nuts to seal the studs. My rear end is totally dry, and the differential doesn't leak either.

What's with the stack of washers on the pinion flange? They will not allow correct torque to be held. If the bolts are too long, get the correct ones. They are available form Ford and many suppliers and the correct bolt is called a "place" bolt, you know the ones with the shallow castlelated heads? This allows the bolt to "lock" as the underside of the head is convex and the bolt head deforms slightly to give a locking action to the bolt. And Ford uses copper washers under the pinch nuts that hold the carrier to the axle housing.

Be aware that some gear ratios are timed. The number of pinion teeth verses the ring gear teeth are such that the same teeth always contact each other in a repeating pattern. Do not pull the pinion without first knowing how (if needed) to time the gears.

Second thing. The pinion flange has shims, not gaskets. This is what sets how the teeth contact each other. Do not change the shims or put sealer on the shims. It seals with an "O" ring internally.

Never heard that one before timing the gears,certainly understand the reason why.All the 9" rears using old gear sets never been a concern nor have we ever had a problem with excessive wear.
Very curious though is there a particular brand name of gears sets we should be aware of?

I am only pulling the main flange on the differential not messing with the front pinion flange or shaft. Shouldn't I be able to pull the axles and drop the main body with no worries? Also the washers were there for the emergency brake mount assembly spacing.

If I drop the main assembly do I need to mark the pinion shaft to keep it the same and mark the axles to keep them the same?

Some things to think about: I can't speak to the timed gears which I doubt you have based on the stack of washers allowing the use of long bolts. If you know anyone that has a transmisson jack you can borrow that would help a bunch. They sell transmission jacks at Harbor Freight for about $35 which would work fine for no more than you are going to use it. The axels only need to come out about 8" for you to pull the pumpkin. Once you have it out clean both the gasket areas of the pumpkin with brake cleaner or Lacquer thinner. I like using black RTV silicone instead of the gasket but to each their own. I use a caulking gun with a tube of the black silicone from NAPA #550 (or something like that). If you have trouble getting your fill plug out you may have to put a little heat on it with a propane tourch using MAP GAS. I think it will take 2 1/2 quarts of 90w-140w gear lube.

Good luck with your project.

Clois Harlan

I am pasting an explanation:
Non hunting, the tooth on the ring gear lands on the exact same tooth of the pinion every time. 3.00:1 perfect example.
Semi hunting, the same tooth lands on the same teeth on the pinion gear every time, but not just the one tooth and not every tooth. 3.50 and 3.33 are examples.
Then hunting patterns where a single tooth on the ring gear will eventually touch every single tooth on the pinion gear after enough revolutions.

Some sources point this out and some do not. I do know that typically after a gear set is machined, they are set in a machine, coated with a polishing compound, and then ran together. Most all sources say that gears are a matched set (they are numbered) and cannot be mixed. If the ratio is a non-hunting or semi-hunting, there should be marks on the teeth of each gear to indicate how they were timed, when they were polished together.

My 3.5:1 gear set were marked, when I took them out. Some sources say they paint the marks. The paint may wear off over time.

I have read one source on the net that claimed CNC machines are so accurate today that timing gears is no longer needed. Well not all gears are produced on modern CNC machines. More importantly, I have worked with a company that made gears for a pump that pumps molten plastic. They told me that a CNC machine leaves tiny lines on every pass that needs smoothed out, and CNC cut gears need to be ran together to polish these out. From this, I believe it is still important.

My gut tells me that a set of non or semi hunting gears that have a 100K miles on them, would be worn together. Changing which teeth contacted (timing) on those gears would be worse than not timing a new set. That is why I cautioned the OP.

I have no doubt that many people have not known any better and put non-hunting gears in without timing them properly. Maybe they get a little more noise than they would have, but I doubt it causes any real problems. Maybe if the gears were not cut very well and they relied on a lot of polishing, it would matter. After they wear in, it may result in more backlash.

Ring and pinions do come as matched sets but there is no timing involved. Pinion depth, backlash and bearing pre-load but no timing. Kirk is only changing the gasket to fix a leak, no need to mark the axles or anything else. I would'nt go and buy a jack for this either, it would only make it harder. Get a friend to help if you need to but its not that heavy.

Wellllllll-----

There are gear sets that have been made that are non hunting and should be installed correctly--However, these gears are in the smaller ratios and only happen with simole numbers--that is a ratio that is a number that when you devide the number of ring gear teeth by the number of pinion teeth you won't have a fraction or remainder---4.10---41 ring gear teeth, 10 pinion teeth is one commonly used ratio that fits this scenerio--a 4.11 does not--
the present day gears you buy may not be marked as to which teeth you mesh together, but on those the same teeth is touched each revelution by the same pinion teeth---

The other ratios that don't devide out to a whole number will eventially touch every tooth with every tooth on the pinion---So, it is a fact that these hunting gear sets will outlast a non-hunting ratio if a tooth is broken off, but its over when its over.

Back in the 40s,50s,60s it was vital to mesh the paired teeth when setting up a gear set or you would have noise, tight spots and looser spots--with the lower set pinions it became more important to set the depth of the gear along with the backlash and the manufacturers started the lapping and matching of gear sets----

I stand corrected. I googled it and see what you are talking about. Have you actually had to do it? I have installed at least a dozen ring and pinions over the years and never heard of this and never had a noise or problem.

This is the same as pulling amotor apart and re-using components. Lifters and rockers and pushrods all need to go where they came out of because the parts wear together. That is why on new motor one needs to re-torque and rwtighten a lot of bolts as the motor wears in.

Yes, I have done it---it was especially common 50s and 60s--but only happens with the ratios that don't divide out to a whole number. tooth ratios that divide out to the fartest digit will wear the most evenly?

The nine inch ford gears are the ones with the deepest offset pinions(works more like a screw than a common gear mesh) and the shape of the teeth vary more with the various ratios---some ratios that are close will have huge differances of tooth shape and will result in different parasitic drag amounts---look at the tooth counts of the various ratios and you will get an idea abouth tooth size(and shape)

example --4.0 9/36 10/40

It's been close to a year since I rebuilt my 9", so memory is a little cloudy, but I think the entire 3rd member is around 75 pounds. Depending on the angle you are reaching from, it could easily be more than a person can handle. Slippery when oily.

I had another person operate a regular floor jack to do the heavy lifting, and I steadied the 3rd member on the jack. I think a better jack, that would have supported the 3rd member on its own, would have been very nice to use. Easier and safer.