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LSD Install Help

Peterson

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#1
So I’m up to the process of shimming the Diff, and I ran into a big problem. I heated the Bell Housing fine to get the stock shim out (it’s 0.5 btw). Ultimately, I wasted my time, as the next smallest shim I could even order from Ford was 0.1. It’s so flimsy, that I determined to just put the 0.5 shim back in (massive waste of time lol). In doing so, I heated the Bell Housing back up (almost 20 minutes of heat), had the race in freezer, and even blasted the race with an upside down compressed air can (-15F). The race dropped in about 3/4ths the way no problem, but wouldn’t budge. I was hitting on it with a seal driver as the manual says but it wasn’t budging. I gave up and pulled it back out with my slide hammer. Upon inspection, I realized that it wasn’t seated perfectly straight. I GOUGED THE SIDEWALL WITH THE RACE. You can catch your fingernail on the scratch. Pictures are below.

It is a horizontal scratch, so can I clean up my scratch, smooth it out and all is well with the world? Does it even matter? The shim is behind the race, and the axle seal is behind that. Will this leak fluid? I imagine that it would all be contained behind the axle seal. Do I need a new Bell Housing?

Any advice from experience is welcome!
 


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#2
Maybe get a straight edge and see if it has a lip where the scratch is at and if it does sand down the lip with some 8k grit (something SUPER fine) sandpaper. The bottom of that bore should be perfectly round and the scratched area looks to only be about 1/3 of the total area so theres a good chance it'll still hold up.
 


OP
Peterson

Peterson

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Thread Starter #4
Maybe get a straight edge and see if it has a lip where the scratch is at and if it does sand down the lip with some 8k grit (something SUPER fine) sandpaper. The bottom of that bore should be perfectly round and the scratched area looks to only be about 1/3 of the total area so theres a good chance it'll still hold up.
This is what I was thinking. The shim is under the race, and the axle seal is under that. If I scoured it vertically, I’d think I was in bigger trouble.
 


MagnetiseST

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Dania Beach
#5
I gouged the outer area where the seal goes as well, shallower, but wider. I used some emery cloth to smooth it and used some grey gasket maker when i put the seal back in. It hasn't leaked at all, but I know I probably shouldn't have done that.
 


OP
Peterson

Peterson

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Thread Starter #6
I gouged the outer area where the seal goes as well, shallower, but wider. I used some emery cloth to smooth it and used some grey gasket maker when i put the seal back in. It hasn't leaked at all, but I know I probably shouldn't have done that.
But this isn’t where the seal goes. This is on the inside. It’s the wall where the race goes that holds the Diff shim in.
 


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Brookeville
#7
I'd go with what others have said. Carefully clean up the damage, and reinstall the seals. I will say this - when I did my build, I did exactly what you did - froze the races and heated the case. I used one of those IR thermometers and I had the heat gun on for a very long time - just like you. It took forever to properly heat the case. The first race I installed, I kept the heat relatively close to where the race goes into the housing. Putting it in was a BEAR. It did what yours did - went about half way and then stuck. I had to WHALE on it with a hammer and race installer. But, it did work. For the second race I tried something different. I heated the case but when I heated it I also heated the area about 6" around the hole. Did this for a while. When I pulled the race from the cooler where I had it on ice, the thing literally dropped into the hole. No driving needed. I did check to be sure it was seated and all and everything was perfect. I think heating the case further from the hole will cause it to open up a bit more. Anyway, hope this helps. GOOD LUCK.
 


JDG

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#9
So I’m up to the process of shimming the Diff, and I ran into a big problem. I heated the Bell Housing fine to get the stock shim out (it’s 0.5 btw). Ultimately, I wasted my time, as the next smallest shim I could even order from Ford was 0.1. It’s so flimsy, that I determined to just put the 0.5 shim back in (massive waste of time lol). In doing so, I heated the Bell Housing back up (almost 20 minutes of heat), had the race in freezer, and even blasted the race with an upside down compressed air can (-15F). The race dropped in about 3/4ths the way no problem, but wouldn’t budge. I was hitting on it with a seal driver as the manual says but it wasn’t budging. I gave up and pulled it back out with my slide hammer. Upon inspection, I realized that it wasn’t seated perfectly straight. I GOUGED THE SIDEWALL WITH THE RACE. You can catch your fingernail on the scratch. Pictures are below.

It is a horizontal scratch, so can I clean up my scratch, smooth it out and all is well with the world? Does it even matter? The shim is behind the race, and the axle seal is behind that. Will this leak fluid? I imagine that it would all be contained behind the axle seal. Do I need a new Bell Housing?

Any advice from experience is welcome!
Comparing your photo to my bell housing on the bench, it looks like the scratch will be fully covered by the race, correct? As in no part of the scratch protrudes into the area where the seal is seated, correct?

If both are true statements, just make sure you debur the highest points of the scratch to ensure the burs will not inhibit the race installation (with emery cloth) and you should be good to go.

Please update this thread with your final shim stack height as well as your preload mesaurement after assembly. I know myself and a few other folks will be curious.

@jeffreylyon - FYI
 


OP
Peterson

Peterson

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Thread Starter #10
Why am I more nervous to sand this down than I was with taking the whole transmission apart? 🤣
 


OP
Peterson

Peterson

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Thread Starter #12
Again....which LSD is being installed? Some members have utilized certain LSDs and no shims were needed. FYI.

Sent from my SM-N975U1 using Tapatalk
Sorry. Quaife.
Honestly, my Diff races seated perfectly to the stock numbers

1.7mm on top
6.0mm on bottom

so maybe all is for naught.
 


Last edited:
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Metro Detroit
#13
Some thoughts concerning heating the bell housing. First Aluminum is one the three most conductive metals, the only metals that are more conductive is Copper and Silver. BTW Silver is that most conductive metal known.

Because of this if you only heat a localized area any unheated areas will suck all your heat input out of that spot where you need it. I believe that the reason for those bearing races "stalling" isn't misalignment, it happened because that area had cooled below the critical point. The solution to this problem is to heat the entire bell housing. If you want an easy way to actually do that, test to see if that bell housing will fit in the oven in your kitchen. If it does you have your heating device. Note, most ovens on the lowest "warm" setting will heat to 130-140 degrees. It's a good temperature to get locktite to release. In this case I think the ideal temperature would be in the 150-160 degree range. Just make sure that bell housing is soap and water you can eat soup out of it clean. Otherwise you'll fill the house with all kinds of nasty smells and probably set off the smoke detector. Then there is the matter of what your better half might have to say about the clouds of smoke and toxic fumes. BTW, a large gas grill would also work if you have one, just keep an eye on the temperature because most have no thermostat.

BTW, Harbor Freight sells a non contact infrared thermometer for around 24 dollars IIRC and these are something every one should have in their tool kit. Once you have one you'll find them very useful to check the temperature of lots of things. Want to know how hot your intake is, aim it at your throttle body. I'll also note that you will want to good insulating gloves, Harbor Frieght also sells some decent Welders gloves for about 1/2 the cost at a welding supply shop.
 


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Location
San Jose
#16
What were you using the driver handle for that caused it to get damaged like that? to get it back out (if so i found a bearing driver that was near perfect size and tapped it out from the back side, link below)? I think i have the same kit(second link), there should be a end of the bearing driver that fits perfectly on the race, a few good taps should get it to seat unless it is caught on that same lip. (though from your picture it looks like it should already be past that).

Kit I used to tap it out (https://www.amazon.com/gp/product/B07G7971WL/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1). When the shim was not in there being careful with a flat head screwdriver is best.

Kit that fit perfect to make sure the race was fully seated (to tap it in )(https://www.amazon.com/gp/product/B005SMUOR4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1)

For heating, don't worry about the whole case, just heat around the race. I used this gun (https://www.amazon.com/gp/product/B01M020KO1/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) set at 1000 degrees for ~8 minutes focusing on only the area around the race. While I did that I kept the race in ice/salt water, and made sure to wipe it off REALLY GOOD before dropping it in.

The Qualfe should fit to the same shim as stock.

As a general FYI if you/anyone needs a different size shim, this post has a list of part numbers
https://www.fiestastforum.com/threads/lsd-installation-thread.2390/page-4

Part Number, Part Description, Quantity, CorePrice, Price, SIZE

YS4Z4067KA SHIM-TRANSAXLE DIFF 1 $0.00 $35.21 .10

91WZ4067LA SHIM-TRANSAXLE DIFF 1 $0.00 $3.17 .20

YS4Z4067AA SHIM-TRANSAXLE DIFF 1 $0.00 $5.78 .30

YS4Z4067BA SHIM-TRANSAXLE DIFF 1 $0.00 $5.78 .40

91WZ4548CA SHIM-TRANSAXLE DIFF 1 $0.00 $55.52 .50

YS4Z4067DA SHIM-TRANSAXLE DIFF 1 $0.00 $6.01 .60

YS4Z4067EA SHIM-TRANSAXLE DIFF 1 $0.00 $6.08 .70

YS4Z4067FA SHIM-TRANAXLE DIFF 1 $0.00 $32.30 .80

YS4Z4067GA SHIM-TRANSAXLE DIFF 1 $0.00 $3.78 .90

YS4Z4067HA SHIM-TRANSAXLE DIFF 1 $0.00 $6.84 1.00

YS4Z4067JA SHIM-TRANSAXLE DIFF 1 $0.00 $3.94 1.10

For my wavetrac i ended up needing a .30. A local ford dealer is ordering it for me.
 


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Location
Brookeville
#17
Is this the race part number from your list?
That's the outer oil seal, not the bearing race.

This is the OEM part number for the diff bearing/race: 96WZ-4220-AA. I was unable to source it. Even though the sites list it as available, it was not. Now, things may have changed since then! Call Tasca and the others to find out if they can actually get it. I ran into dead end after dead end and eventually ordered it from 123Bearing.com in France. Yes, France. (and the parts arrived only a few days later! Amazing. Tasca screwed me and took over a month to get me parts.:confused:) https://www.tascaparts.com/oem-parts/ford-manual-transmission-differential-bearing-96wz4220aa

I purchased this Timken bearing cone/cup, which is the same bearing specs as the OEM one. I took careful measurements and worked with knowledgeable friends to be sure. It matched every spec I could find when I cross referenced the OEM part which is an INA bearing. Here is what was on my OEM diff bearing:

DIFFERENTIAL BEARING
INNER RACE
NSK LM29749 (a∝) CHINA 20130819R
OUTER RACE
NSK R38Z-24 CHINA 20130818
OD 65mm


https://cad.timken.com/item/tapered...gs-ts-tapered-single-imperi-2/lm29749-lm29711
Series
LM29700
Cone Part Number
LM29749
Cup Part Number
LM29711
 


OP
Peterson

Peterson

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Thread Starter #18
You guys have been a great help so far! I feel as if my casing is shot from beating on it so much. I’ve ordered a new one for $144, so it’s not the end of the world.

I need to buy the outer race cone as I can catch a fingernail on the middle of mine.

The old case and cone I beat up will be a learning tool now to find a better end goal temperature to heat to. Live and learn 🙂

Besides, the old case will make a great garage wall trophy now 😂
 


OP
Peterson

Peterson

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Paramus, NJ, USA
Thread Starter #19
Nice! There's a Ford deal 15 minutes from me that's open for business in NY.
https://parts.schultzford.net/

Almost $50 cheaper than parts.ford.com

Part Number C1BZ-7005-A
Part Name Case Assembly - Trans-Axle
Price $137.64
Total $137.64

Subtotal: $137.64
Local Pickup: Free
Tax: $11.53
Total: $149.17
 


OP
Peterson

Peterson

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Thread Starter #20
So here’s my pre load math:

Diff Float: .33, .35, .34
AVG float: .34

Measuring Shim: .1

Ford Preload: .14

.34+.1+.14=.58

The stock shim was .5 and there is no .58 shim so I round up to 6. Seems like the Ford Performance way of just dropping the LSD in and you’re good to go might not be so correct.

MY QUESTION:
CAN I STACK MY .5 & .1 SHIMS???

Or do I have to source and buy the .6 shim?
 




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