Rear End Gear/locking diff install...Some questions.

[Kona6Stang10]

I know there are some people on here who do gears and differentials themselves...so, I have some questions for you guys.

About how long should I plan for these mods to be installed correctly?

What tools will I need? (IE: any specialty tools, as I have shop tools etc)

As far as making sure Backlash is set right....could I just use a combination of shims to make the same sort of specs as stock?

I have a tuner so getting the new gear ratio plugged in won't be a problem.....

Break in:

What is the recomended break in for new gears and locking differentials?
I've heard it's around 500 miles with easy throttle and not remaining at a constant rpm so that the parts can get used to the heat cycles ?

Thanks in advance guys!

 

[Kona6Stang10]

Bump! I figured there would be a lot more input from the S197forum crowd.....

 

[GrnBullitt08]

Answers are in bold boss

I know there are some people on here who do gears and differentials themselves...so, I have some questions for you guys.

About how long should I plan for these mods to be installed correctly?
It takes about 4 hours with a lift, if your doing it on the ground minus a lift plan on a full days job
What tools will I need? (IE: any specialty tools, as I have shop tools etc)
You'll need a dial indicator to check back lashing, a ft lb torque wrench and a inch lb torque wrench, dial or digital calipers, a pipe for torqueing the pinion nut, a hydraulic press machine to press on new bearings (or just have a shop do it)
As far as making sure Backlash is set right....could I just use a combination of shims to make the same sort of specs as stock?
yes you will use a series of shims to ensure backlash is correct... Pinion depth also plays a role in this a must be within .002-.004" of desired spec, backlash should fall between .006-.009"
Pinion pre-load also plays a vital role, for used bearings which I don't recommend your looking for 14-16 inch pounds of resistance, new bearings 23-26 inch pounds.
I have a tuner so getting the new gear ratio plugged in won't be a problem.....
Yes you'll be fine with the handheld, just go to adjustments and select new ratio, then enter in your revolutions depending on tire height etc...
Break in:

What is the recomended break in for new gears and locking differentials?
I've heard it's around 500 miles with easy throttle and not remaining at a constant rpm so that the parts can get used to the heat cycles ?
Yup, 400-500 miles should be sufficient

Thanks in advance guys!

 

[GrnBullitt08]

Make sure that you install new races and bearings with your new setup, and be sure that your ring bolt are torqued properly, I've seen those back out a time or two.

75-140w Royal Purple or a full synthetic gear lube is what your looking for, 4 oz friction modifier if it's not already in the lube, royal purple already has it in their gear lubricant.

Use gear marking paint to test for appropriate wear on the ring gear...

All this should come with your rebuild kit.

 

[Kona6Stang10]

Thanks so much Grn!!
I don't have a lift, but I do have almost all of those tools with the exception of digital calipers and a hydraulic press.

So once I order my kit, i'll be on my way!
Thanks for the tq specs and proper measurements too!

BIG HELP!

 

[19COBRA93]

You'll definitely need access to a press. Take your time, and don't settle for "close". Get it dead right. You see all these threads about "My rearend whines with new gears", it's because the installer settled with "close". It can be a pain in the ass, but it's a LOT harder to do it a second time to correct it, than to spend some extra time the first time setting it up right.

 

[GrnBullitt08]

Thanks so much Grn!!
I don't have a lift, but I do have almost all of those tools with the exception of digital calipers and a hydraulic press.

So once I order my kit, i'll be on my way!
Thanks for the tq specs and proper measurements too!

BIG HELP!

No problem, and goodluck with the install.

You'll definitely need access to a press. Take your time, and don't settle for "close". Get it dead right. You see all these threads about "My rearend whines with new gears", it's because the installer settled with "close". It can be a pain in the ass, but it's a LOT harder to do it a second time to correct it, than to spend some extra time the first time setting it up right.

I agree, take your time and make sure everything is spot on, if not you'll pay for it later.

 

[stkjock]

are you changing the diff? if so what diff r u going with?

Also, 3 heat cycles to start and take it easy for 400-500 miles.

 

[TexasBlownV8]

American Muscle has a good writeup on the gear install, including the backlash/clearanc specs I think. Also, what I've always used, is the Ford Service Manual (look for the link to it; it'll be for a '07 but the procedures and specs are the same).

You CANNOT just replicate the stock shims for backlash. Even using the same carrier, using just different gears will likely throw off the backlash, requiring the use of different shims. If it happens to come out the same for you, then great. Otherwise, hopefully you can swap which spacers go (they are different on each side of the carrier, so be careful when you remove them!).

Proper backlash is critical for minimizing whine.
Checking for ring gear run-out is critical to make sure the ring gear is in there properly ( and not sitting a little crooked on the carrier, which I had happen once ).
Proper pinion depth and pinion preload (in INCH-POUNDS), is critical for pinion life and preventing growling.
And as mentioned, properly securing various bolts (ring bolts and pinion nut with loctite) is critical in getting things to stay together.

 

[Kona6Stang10]

are you changing the diff? if so what diff r u going with?

Also, 3 heat cycles to start and take it easy for 400-500 miles.

Yes, the diff is getting changed....right now I have an open diff....which sucks....I'm just going with the ford T-lok and 4.10's.
I figure I'll never make enough power with my mods to break the t-lok.
THanks!

American Muscle has a good writeup on the gear install, including the backlash/clearanc specs I think. Also, what I've always used, is the Ford Service Manual (look for the link to it; it'll be for a '07 but the procedures and specs are the same).

You CANNOT just replicate the stock shims for backlash. Even using the same carrier, using just different gears will likely throw off the backlash, requiring the use of different shims. If it happens to come out the same for you, then great. Otherwise, hopefully you can swap which spacers go (they are different on each side of the carrier, so be careful when you remove them!).

Proper backlash is critical for minimizing whine.
Checking for ring gear run-out is critical to make sure the ring gear is in there properly ( and not sitting a little crooked on the carrier, which I had happen once ).
Proper pinion depth and pinion preload (in INCH-POUNDS), is critical for pinion life and preventing growling.
And as mentioned, properly securing various bolts (ring bolts and pinion nut with loctite) is critical in getting things to stay together.

Much appreciated sir! I didn't know you could make the pinion gear set crooked....that's good info to know!
Whenever I do the install I'm going to take a WHOLE day if I have to so that everything is set in there PERFECT!
I'll also have some help of course.

 

[GrnBullitt08]

Rear end building is tricky business, just take your time and double check everything. Goodluck with the install.