Dissecting/troubleshooting a 7.5" IFS Taco front diff

[silvertoy]

I'm trying to troubleshoot an issue with a front diff. I guess this may be an experiment at this point but it's a good learning experience...this is all new to me. So I've got the 4x actuator motor off. I've got the 10 bolts off that hold the clam shell together. I've hit it hard with a 4lb sledge and screw driver to separate the clam shell but it's not budging. Am I just being a puss and not hitting it hard enough or am I missing something? There's a place where the 2 parts meet where it looks like you can use some type of prying device? Anyone have any experience with this? There's also 2 recessed looking bolts minus their heads...I guess this is to keep it lined up?



It looks like you can stick something in here to pry apart?



The carnage:

[gregers05]

when i took mine apart i think i used a sledge and a crowbar. dont remember where i put the crowbar, i think it was just in the crack somewhere

[silvertoy]

What was wrong with yours?

[gregers05]

Originally Posted by silvertoy

What was wrong with yours?

it was my old one that i tore up the spider gears on a while ago when i was still on 32s. still sitting in the basement in two pieces too lol

[*Darcy*]

i'm pretty sure colin has taken his apart enough times to give some pointers (you have to to get to the spider gears, correct?) ... he'll probably give some input on this later...

good luck!

[GOT COPE?]

You're being a puss Thad

I typically use a 24oz ball peen hammer, but whatever is close or heavy will work.

You have to hit those tabs, a couple whacks at a time, then rotate. Just keep going around and eventually it will crack open. If its stubborn just hit it harder. Keep rotating till its completely off.

Ive personally hit mine so hard it was uncomfortable at times. I do imagine those tabs could break if hit hard enough.

Those pins are there to line it up and to provide some strength Im sure. Kinda like the pins on our hubs, if you have manual.

And I'm 110% sure those are spider gear teeth you've broken.

As far as replacing those, drive out the pin (will require a punch) holding in the cross shaft, remove the shaft, remove broken spiders, install new ones (dont forget the thrust washers), may take a try or 3 to get the spiders lined up, put the cross shaft back in and tap the pin back in with the punch.

If the cross shaft wont come out due to the ring gear, remove the ring gear (will probably require an impact), then do the above. Then reinstall the ring gear, use locktite on the bolts, find the torque specs somewhere, it isnt coming to me right now.

Then put the diff back in the clamshell, (make sure to spray the clamshell out good and wipe out all the spider debris) and put the two halves back together, (dont forget the RTV) and bolt it back together. I just tighten it best I can with a ratchet. No torque specs.

And Ive never had a problem doing it this way. Not that Im aware of.

Below in the yellow pan you'll see the cross shaft that goes into the carrier and through the two smaller spider gears. Roll pin is in there somewhere. Thrust wahsers are on the spiders, 4 total, two domed on the smaller and two flat on the larger.

And FTR I was just taking a pic of the larger spiders, my broken one on the left and one believed to be from an 8.4 rear on the right that I had recieved in error for a replacement.

[silvertoy]

You are the man, spider man, thanks a ton. I will give it another go.

[tlh89]

I got a front diff you need Thad

[silvertoy]

Looking to upgrade to 4.88, what you got?

[tlh89]

4.56 with arb CHEAP

[silvertoy]

So cracked it open this morning and here's the carnage. Ring & pinion look fine.

[GOT COPE?]

Ah Christian must've given it a farewell thrashing

He told me he'd never noticed.

I know each time Ive broken mine it has been bad enough to make an obvious noise.

His doesnt look as bad as mine did. The little spiders were completely sheared off.

[silvertoy]

Yeah I know how Christian drives, with a lead foot Anyway, I figure I'd make this into a mini tutorial while I'm at it.

So, remove the 10 bolts holding the two clams together. Air tools work wonders for this.

I found it easy to separate the two halfs by tapping a screw driver where the 2 halfs meet. Keep prying from side to side until they separate.



I marked all the pieces with silver Sharpie pen before disassembling so we know how it goes back together:



There are six torx head bolts holding the ADD diff tube on, use an "E14" external torx bit to remove.



Unfortunately whoever regeared this diff screwed up 2 of the torx heads. So, tried the slotted screw driver method but that wasn't working.



Ended up having to use the grinder and grind off the head of the torx bolt. Once that was off, take a screw driver and hammer and gently tap around the head to pry the remaining metal up. I took a vice grip and was able to unthread the bolt:



All the pieces disassembled:

[benny_wiskas]

I wish I had seen this earlier. You didn't have to mess with the torx bolts to get the clamshell apart.

Are you now trying to get the carrier out? If so, you just take a crow bar and gradually pry it out. Don't be afraid to use force, because it takes a quite a bit. There's a little c-clip in there similar to the clip on the end of the cv. It'll just pop off.

[benny_wiskas]

I found this a writeup a while back. It's to install a lockrite, but it shows the disassembly process.
http://www.teddnet.com/LockRightInstall.pdf

[silvertoy]

Thanks Kyle, I'll do some reading and try again.

[silvertoy]

Alrighty, continuing on with the tutorial for dummies...

Using two crowbars, one on each underside of the ring gear, forcefully pry upwards with equal pressure on both. After some swearing and cursing the casing will pop off.



Next, pry back the the security clips with a flathead screwdriver. Using a 17mm socket and impact wrench (a lifesaver), unbolt the ring gear bolts and 5 clips.



Then gently tap on the back of the ring gear with a screw driver and hammer switching sides as you go. It should pop right off.

[benny_wiskas]

You're making progress. Got your ring gear in the oven??

[silvertoy]

Nah, not yet, need some spiders first. Know anyone with a set?

Drill out the hole with a 1/4" drill bit.



Flip the carrier over and use a punch to punch out the retaining pin.



Once the pin is out punch out the cross shaft.



Rotate the gears and the spiders will fall right out.

[silvertoy]

Doesn't the lock-rite locker replace all the spider gears? Heck, that might be a better option.

[benny_wiskas]

The lockrite replaces the spider gears. You still use the thrust washers though.

[crawlrunner]

I guess its always the smaller spider gears that break first? Lock-rites break too. Just clean up, reassemble & weld 'em up .... JK! Good luck on finding some gears Spiderman's probably hording them all!!!!!! HA!!!!!!!!!

SASSASSASSASSASSASSASSASSASSASSASSASSASSASSASSASSA SSASSASSASSASSASSASSASSASSASSASSASSASSASSASSASSASS ASSASSASSASSASSASSASSASSASSASSASSASSASSASSASSAS!

[silvertoy]

Donor diff acquired tonight, 4.10 ratio, stock 7.5. Donor carrier on the left, new spiders installed on the right. Disassembly went much smoother this time. Don't forget to punch down the metal around the top of the pin hole to hold the pin in that holds the cross shaft.



The stock 4.10, never touched or modified had a huge chunk missing, ouch!

[TRoss]

So are ya re-gearing too?

[crolison]

you have an extra add diff tube thad?

[silvertoy]

I do now...2000 Taco diff tube....btw it looks different from Christian's 2001 diff tube...you interested? You can see the end of it a couple of pics up with the red sealant.

Originally Posted by crolison

you have an extra add diff tube thad?

[silvertoy]

Yeah, trying to repair Christian's 4.88's.

Originally Posted by TRoss

So are ya re-gearing too?

[Phil88]

i think i have a set of spiders you can have id just have to findem
nm i see you found some..

[gregers05]

all the diff tubes should be the same. i had daniel 04 front diff on my truck for a while, but when i bought phils('98 front diff i think?) i switched the axle tubes since i didnt have manual hubs. but i may be wrong?

[link817]

good deal thad. little noises go away w/ a bit of stereo.