Rear Diff fluid had been drained!!! WHOOPS!!

[commercialcobb]

Well, it was the first time the car has been driven in 4 years. The car has been in the shop almost 4 years and at some point, some jackass drained the rear diff fluid and replaced the drain plug without re-filling the fluid. I assumed that since there was no rear-end work done what-so-ever that there would have been no reason for someone to drain the fluid. That's what I get for assuming. Now, I am going to have to replace the ring and pinion and all the bearings in the Ford 9" 3rd member. Is there a good set I should be looking for? Is the Summit racing street/strip ring and pinion OK?? And finally, how hard is it to replace these burned out parts in the 3rd member. Is this something that I can reverse engineer or should I just turn it over to a professional? I would like to do it myself and I have considerable shop knowledge and skill but this is something I have never attempted.

[olddog]

I have never done one, but my son has done several. He says it isn't that hard to do. Talk around to people in your area and find someone who has done it before. Tear it down and carefully lay out the parts. Pictures will help. Clean it up and get it ready to go back together. Then after getting new parts. Have that someone you found slide by and help you set up the back lash.

Maybe someone with more knowledge will comment. By the way a year or so back someone had a link or a file of an exploded view drawing of a 9". Do some searches on this forrum.

Good luck

[commercialcobb]

I found the exploded view of the 9" on google.. But a guy that wants me to pay him to do it said if I don't get it right, it will whine and vibrate.. Did he say that so I'll pay him? Do the gears need to be timed or just fitted together?? I need to do some more research but just wanted to see if there were any whistle blowers in here with a good reason not to attempt it by myself..

[elmariachi]

You'll need a dial indicator and a few tools, and it can be a tedious job. Go here for an overview of an 8" re build:

http://www.mustangmonthly.com/howto/41618/index.html

There are lots of sites and a few DVDs out there that walk you through it.

[undy]

Your best gears for the buck are your Motive street/performance series.
http://store.summitracing.com/egnsea...6&autoview=sku
Be careful on the gears you buy. Stay away from the "drag" gear as they are too ductile and soft for street use. When you order your bearing kit you'll need to know whether it's 28 or 31 spline, pinion shaft crush sleeve or solid spacer/shims and your existing carrier bearings' OD of the outer race.

I'm assuming that you drove it without rear lube for a period of time. If so and you have rear differential fluid lubricated axle bearings they made need replacing too. When you pop the axles you can do a closer inspect on the bearings. Look for bluing or other signs of overheating (melted seal lips, fried grease etc..).

You might want to take a look at your posi unit too. Some of the crate rear end posi carriers were crap from the start. Without a doubt, the Detroit True Trac is the way to go if you decide to replace it. I've one in my 9" now and both axles grab enough to yank both front tires.

Depending on what your ultimate horse power goals are and if you now have a 28 spline setup, this would be the optimal time to go 31 spline ... and to provide your own contribution to our much needed "economic recovery stimulus".

Dave

[Bonos]

Being that you have a 9'' you can remove and replace the entire hogs head with another unit. you can inspect the axels as "undy" had stated when you pull the axels to replace the hogs head.when axels are out count the splines to find out if you have a 28 or 31 spline.
THE JOB IS VERY EASY IF YOU ARE ONLY CHANGING THE HOGS HEAD UNIT.

Bonos

[Rick Parker]

As Bonos mentioned above, replacement of the gear carrier is relatively easy to accomplish. As far a replacement of the ring and pinion, it requires experience to know the right "Feel" for the assembled pinion after replacement with new bearings. You must also have as mentioned some specialized heavy duty tooling, including hydraulic press, adjustable bearing clam shells to remove and replace the bearings, a vast assortment of different shims, a large capacity torque wrench that approaches 200 + lbs, and a very stout LARGE VISE to hold the companion flange while the retaining nut is being torqued. Most of these are not in our home shops. This is a job best left to a professional shop that does this often. Considering your location in the Heartland of Nascar, you should have no problem finding a shop capable of doing this. With access to the correct tools and some written an illustrated information this is not an overly difficult job. However it is not one you want to take chances with. The learning curve is steep, even if you have access to the tools. If the gear meshing pattern is incorrect or the bearing preload too loose or too tight you will be buying a 3rd set of gears. Repeat: "Best left to a pro."
I would also suggest using a machined bearing spacer instead of the collapsable one that is more commonly supplied because it will maintain the pinion bearing preload much better, especially with an engine such as yours that develops a lot of torque.

[commercialcobb]

I moved this post to the "shop talk" forum and updated alot of info and pics.. If you have anymore ideas whit what info I have provided there and also would like to join the discussion, i welcome your input in the new thread... Thanks a bunch for you help so far, it's obvious that I need it...

[blykins]

I sell Motive 9" gears. Shoot me an email if you need a price.

brent@b2motorsportsllc.com

[kitcarbp]

Was this burned up pinion bearing the source of your swerving topic on another post or was more found in reqar susp to contribute ?