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replace side and spider gears as set?

BK_89iX

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November 26, 2004
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City, State
CA
Year, Model & Trim Level
'97 SOHC
I have my 3.73LS carrier apart, waiting on bearings, and I'm not really liking the look of the spider gears. Teeth are pretty tapered sighting down the top. New clutch pack is going in and gears are out. Can I replace just the smaller spider gears, or is there some reason I would need to do the side gears at the same time for a proper mesh?

BK
 



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The spider gears are 4 small gears that mesh together that sit inside the carrier. Pictured below (well, theres 3 of them in that pic anyway) (EDIT: this pic is from the diff I had to replace, its a junker)

picture.php


They need to be replaced as a set because they wear on eachother. That "S" spring can be a royal pain in the butt though.
 






Yeah, it's a matched set. You may just want to replace the carrier itself. Even if you switch it over to an open to save some cash. Chances are w/ the mileage the clutches are worn too and it's acting as an open diff at this point. I just figure w/ all the trouble of doing the spiders it would suck if it still didn't work after the fact.
 






Thanks, guys. I asked because I see them available separately from Ford, and my side gears look fine. I guess formally the larger side gears and smaller pinion gears go together to make up the "spider" gears.

Looking at the pic from pos, maybe mine are not so bad. My pinion gears are also tapered like that....4mm at the top and 2mm at the bottom with some pitting on the contact surface. Most of the pics I've been able to find show what look like 4mm from top to bottom of the top, non-contact surface (straight cut).

New clutch pack is going in, so LSD function will be refreshed. Old clutches actually looked pretty good, although the first friction against the side gear was worn down to metal and the stack height was below spec. The S spring was a b*itch to get out, so I can only imagine the fun getting it back in...

I think I'll cry if this thing does not work after it goes back together. Grown man. Not pretty.

BK
 






That pic is from my JUNK rear differential. Maybe I should have stated that in my post. Pitting on gear surfaces calls for replacement of the spider gears.
 






That pic is from my JUNK rear differential. Maybe I should have stated that in my post. Pitting on gear surfaces calls for replacement of the spider gears.

How does the saying go? In for a dime in for a dollar...

BK

Update: $71 for a set of four spiders from our friends at tousley - small price to pay for some peace of mind. If I had to start over I would probably just spring for the whole carrier assembly.
 






Got the spiders today. The instruction sheet that came along said to NEVER mix gears and only install as a complete set. The appearance is somewhat different - new ones look sort of cast as opposed to machined.

The old:

166bpq9.jpg


The new:

ip0e2u.jpg


Comparison:

1zgbz9k.jpg


BK
 






Got the spiders today. The instruction sheet that came along said to NEVER mix gears and only install as a complete set.

Have you given any thought to stacking your clutch packs differently?
I have been contemplating replacing my spider gears and rebuilding the clutch packs and have been reading up on it. It seems that the Mustang guys stack the frictions/steels differently to gain better traction.
You can read up on it here:
http://www.allfordmustangs.com/forums/5-0l-tech/118464-how-rebuild-your-8-8-rear-end.html

They give step by step directions and the first post gives a link to an article with alot of pics associated with it. Its more about rebuilding the entire differential and swapping out the gear ratio, but you can filter out the information you don't need.
 






Yes, I studied up a bit on different stacking schemes. I decided to use the format explained in a youtube video - segment from a commercial DVD. Steel, Friction, Steel, Steel, Friction, Steel, Friction, Shim (total stack height 0.640-0.645" wet). My Explorer already has the stiffer S spring. Don't want to cram in an extra friction plate or other tricks for this particular vehicle. Thoughts?

BK

http://www.youtube.com/watch?v=0GsLDg3C6Hc
 






That is the (stock) stacking order that Ford recommends for this axle. I think the F-150 S-spring is a little tighter, but for every-day street driving it really wouldn't matter much, plus it would be even more of a pain to get it installed. I guess it depends on your driving habits and the end use of the vehicle.
 






That is the (stock) stacking order that Ford recommends for this axle. I think the F-150 S-spring is a little tighter, but for every-day street driving it really wouldn't matter much, plus it would be even more of a pain to get it installed. I guess it depends on your driving habits and the end use of the vehicle.

My '97 was stacked from the factory [F-SS-F-SS-F-shim], which I guess was the old method.

The youtube video suggests what is now apparently the Ford recommended order [S-F-SS-F-S-F-shim]. This has the effect of utilizing more of the first first friction surface facing the side gear because the steel plate is much wider than the side gear surface.

My original side gear clutch surface is ~8mm wide.

New side gear clutch surface is ~11mm wide.

Friction plate has ~15mm of friction material width.

The tall S-spring, often referred to as the F150 spring, came stock on my '97. I think the difference is like 0.2" in height. It's going to be fun getting that bugger back in...

BK
 






This pic shows the old vs. new side gears and their corresponding clutch plate contact surfaces:

11m5lw5.jpg


BK
 






The old gears look like they have more tooth contact area than the new gears. also, as you pointed out, the new gears appear to be a crude rough cast, where the old ones look like the steel may be better.. Personally, i think the old gears look cherry and i'd reinstall them in favor of the new gears (as i think the old ones are higher quality)

edit: maybe not... i dont know what i'm talking about anyway :b
 






The old gears look like they have more tooth contact area than the new gears. also, as you pointed out, the new gears appear to be a crude rough cast, where the old ones look like the steel may be better.. Personally, i think the old gears look cherry and i'd reinstall them in favor of the new gears (as i think the old ones are higher quality)

edit: maybe not... i dont know what i'm talking about anyway :b

The old pinion gears may have been fine to use, but they showed some pitting, small chips on the back and indications of wear due to the taper. I felt better replacing them, and since this is turning out to be huge project for me I didn't want to cut any corners. I agree that the old gears seem to be manufactured to a higher standard - not sure what the story is there. Here's a zoom of the old ones:

6yyzkk.jpg


BK
 






New clutch plates are stacked and shimmed to spec (0.655" wet). New spider gears are in - they fit great and operate smoothly. I scratched my head about how the heck to get the S spring in. Looks basically impossible considering the force of the spring, the space, and how significantly it needs to compress to fit the opening. My S spring is 45mm tall, and the space it needs to go in is about 39mm wide, not to mention that it needs to be maneuvered past the ring gear. Came across an awesome writeup at moddedmustangs that uses two hose clamps to compress the spring prior to install. Clamps are later removed. I tested it out and I think it's definitely the way to go. Need to get another correctly sized clamp before I actually try it. Here's a pic of the method (from dr. ryan):


4ik0p3.jpg


BK
 






The hose clamp trick works great! For my tall 45mm S spring I needed 4 clamps. I compressed the spring in a vice and then tightened the clamps as far as they would go. Final height after clamping was about 38mm. I used a spare 7/8" pinion shaft to carefully tap the spring into place. Removing the clamps was not an issue. The new spiders look right at home. Hopefully I'll get this thing back into the vehicle tomorrow.

BK

b871hy.jpg
 






My $.02 is to get rid of all that crap. The Trac-Lok Limited Grip is a pos, like all clutch type limited slip diffs. Replace with a gear LS, or a lunchbox locker. Don't know about a helical gear LS, but a lunchbox locker is way easier to install than spiders and clutches and that annoying S spring. Plus, you'll never have to do it again with a helical or lunchbox.
 






My $.02 is to get rid of all that crap. The Trac-Lok Limited Grip is a pos, like all clutch type limited slip diffs. Replace with a gear LS, or a lunchbox locker. Don't know about a helical gear LS, but a lunchbox locker is way easier to install than spiders and clutches and that annoying S spring. Plus, you'll never have to do it again with a helical or lunchbox.

I'm not going to disagree with that!

BK
 






I bought the same spider gears from ford and they look to be cast as well. I think tho old gears are the same, just broken in more. I expect if you look at them down the road they will look the same. The spiders don't do much, and only turn when the wheels are not going as the same speed. I left mine in for now, and they look worse than yours.

Make sure and change the differential fluid after 1200-2000 miles to get all the metal filings out.

aaa080.jpg
 



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Those are some UGLY spider gears! They don't howl or make any noises?
 






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