Rear End Dissasembly Help

[olddog]

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.

[mdross1]

Originally Posted by olddog

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?

[olddog]

Originally Posted by mdross1

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 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.

[cobred]

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.