Rear Diff Questions 82

gr8vet

gr8vet

Well-known member
Joined
Apr 6, 2008
Messages
312
Location
I'd rather be in Bonaire
Remove the readend today, looking to fix seal on pass side. Upon looking around inside, this is what I found. What is the "clip" thing circled in black? It almost appears you can easily pull it out. It kinda flops around very easily, maybe holding a sping in place? The red mark indicates where something at some point caused some wear as it ground against this area. The rear had been into before by someone, for some reason. Big question is about the loose clip for now.

thanks
tt

rear-end-82-008-01.jpg



rear-end-82-005.jpg
 
That loooks pretty normal regarding the clip. It just has some wear on the posi unit. At least that has bee my experience on the aluminum diffs. I have 3 of them, one in the car and two sitting in the floor as spares.
It also looks as if you have some wear on the cross shaft where the stub axles ride and if it is worn there is probably wear on the stub axles as well.
If you are going to build it yourself, dissassenble and clean everything then take measurements of all pieces that have a wear surface. any item not in spec dont comprimize if it is "close" replace it! Get a good kit with Timkins, good seald and a shim assortment to set it up. The most important thing to have for the job is great patience as you will definately need it

I've been messing around for the past couple of years with my own builds with good success, but I recently had a Trackdogg unit custom built out of one of my diffs and it is a work of art with his mods to increase strength and is the quietest differential i have ever experienced in a C3. I have been hammering on it and have been in the 10's with no issues so far. I plan on taxing the aluminum differential to the limit with the addition of juice foggers in the intake. I will be using a controler to operate the juice progressively in attempt to keep the drive line in tact and hopefully get into the 9's
 
The clutch pack retainer clip should wrap around the ear of the inner most clutch platen, yours is bent. As said, the cross shaft is scored also
 
Send it to Tracdogg. After two dinner discussions at SEMA, I am convinced he is the best with these.
He has identified the weaknesses, and deals with them.
 
Honestly, the only way to deal with the weakness is to get a different rear end. Sure, the cast caps are crap but the case is also not machined for the cap mating surface and then there's that funky stepped ridge that the side bearing rests again. There's no fixing that. I'm sure Mike agrees.
 
Thanks guys, I appreciate the info. This is a new one for me to dive into. I am just trying to make sure this thing is well enough to get a few more miles until I can get a few more $. So where will I find the specs on the parts? Clearances, original dimensions, torq specs, etc.

Thanks again, you guys are fantastic.
tt
 
Thanks for the info. Since you guys have been there. :)

I am looking to just have this thing roll down the road, not beat it to death. With that said, the two main reasons I got in there was to replace seal on pass side, and take a look at why I have a bit more end play on this side. The retaining clips where there, and I was able to gentle tap the yoke out. The seal was actually leaking at the case, not on the rubber/yoke. The diff pinion shaft is pretty worn. Clutch retaining clips bent, broke. Bearings and shafts look dang good.

Now; would you replace the little pinion shaft and clutch disc clips, try to adjust the play out on the pass side? Or put the new seal in and button back up. I guess the fear now is if I get to far into it, I could create noise, and other issues without a complete rebuild. Rear end made hardly any noise, just had the leak.

For the life of me I cannot find any torque info on putting this all back together, if we go deeper. I let someone borrow my dang book and can't figure that out either! :cussing:

Thanks guys!
tt

(Oh how I miss the days when I could just call, drop $2K and never think anything about it, they shipped, new parts showed up, install, drive. :surrender: )
 
TT,

According to my 81 manual, the pinion nut is torqued 200-220 ft. lbs. (AFTER the preload and everything else is set), The ring gear bolts are 45-60, bearing caps 60-70 and the cover bolts I didn't see called out.
 
Hey friend, THANK YOU! Printing your post right now.

Gotta find who has my book, hate to buy yet another one :banghead:

Diving on in the whole thing later today, What the hell, I've done everything else on this ride, why not this. LOL

Thanks again!
tt
 
NP! If you need anything else, let me know. As a matter of fact, I have a stock 81 diffy I pulled of mine a few months ago. As it turns out, it's in really good shape, 2.72:1, if you find you need one!
 
Twin_Turbo said:
Honestly, the only way to deal with the weakness is to get a different rear end. Sure, the cast caps are crap but the case is also not machined for the cap mating surface and then there's that funky stepped ridge that the side bearing rests again. There's no fixing that. I'm sure Mike agrees.
Click to expand...

Well, kinda no.
He remachines the case, installs billet caps, then align bores.
He built one that is a 10second car right now. I would say if it handles 650HP, then it cannot be all that bad.
As a matter of fact, in the all the time I have heard about how crappy they are, I cannot recall a failure thread.
Vettezuki and KWPlot both run them with double the stock HP, and have yet to have a stock one fail.
Vettezuki blew his tail piece off his 5 speed, but the diffy is fine.
Mike believes about 50% of them are inherently weak due to core shift while casting, and 50% are just fine.
I have no intention of ever going to cast iron pig.
 
I will have to overhaul the rear diff of my 68.
Leaking all over, and expect that the disc's are worn as well.

Where is a good place for spares of good quality?

I haven't open it yet, but both C-clips are broken of the side yoke. Should I expect any damages to the shaft ends?

Lars
 
big2bird said:
Twin_Turbo said:
Honestly, the only way to deal with the weakness is to get a different rear end. Sure, the cast caps are crap but the case is also not machined for the cap mating surface and then there's that funky stepped ridge that the side bearing rests again. There's no fixing that. I'm sure Mike agrees.
Click to expand...

Well, kinda no.
He remachines the case, installs billet caps, then align bores.
He built one that is a 10second car right now. I would say if it handles 650HP, then it cannot be all that bad.
As a matter of fact, in the all the time I have heard about how crappy they are, I cannot recall a failure thread.
Vettezuki and KWPlot both run them with double the stock HP, and have yet to have a stock one fail.
Vettezuki blew his tail piece off his 5 speed, but the diffy is fine.
Mike believes about 50% of them are inherently weak due to core shift while casting, and 50% are just fine.
I have no intention of ever going to cast iron pig.
Click to expand...

Jeff I'll respectfully disagree, an iron diff- a good one,not one like our friend in Italy got, is better then any of the Dana's.
 
naasaa said:
I will have to overhaul the rear diff of my 68.
Leaking all over, and expect that the disc's are worn as well.

Where is a good place for spares of good quality?

I haven't open it yet, but both C-clips are broken of the side yoke. Should I expect any damages to the shaft ends?

Lars
Click to expand...

Your 68 is not like the one pictured. If original it has a weaker Eaton posi case with 10-18 spiders or even an open diff. Positraction was an option until 1970.
This doesn't mean it's a bad unit, it can be built to handle up to 1000 hp if needed. Look over the threads I have posted here to help you.

Either Mike or I can supply you with the parts will use. DO NOT get sucked into some of the hype on the web, look over some other threads on diffs here to see what I mean!
 
GTR1999 said:
big2bird said:
Twin_Turbo said:
Honestly, the only way to deal with the weakness is to get a different rear end. Sure, the cast caps are crap but the case is also not machined for the cap mating surface and then there's that funky stepped ridge that the side bearing rests again. There's no fixing that. I'm sure Mike agrees.
Click to expand...

Well, kinda no.
He remachines the case, installs billet caps, then align bores.
He built one that is a 10second car right now. I would say if it handles 650HP, then it cannot be all that bad.
As a matter of fact, in the all the time I have heard about how crappy they are, I cannot recall a failure thread.
Vettezuki and KWPlot both run them with double the stock HP, and have yet to have a stock one fail.
Vettezuki blew his tail piece off his 5 speed, but the diffy is fine.
Mike believes about 50% of them are inherently weak due to core shift while casting, and 50% are just fine.
I have no intention of ever going to cast iron pig.
Click to expand...

Jeff I'll respectfully disagree, an iron diff- a good one,not one like our friend in Italy got, is better then any of the Dana's.
Click to expand...

I don't deny that Gary. What I am saying is the Danas are not quite the POS they are made out to be when properly prepped.;)
 
Absolutely and Mike is the guy to set them up with the steel cap. He does them better then anyone and is the only guy I refer those to. Me, hell I hate them but that's just me! I have turned down a lot of them over the years, I stamp my name in my work but not one of those.
 
What is stronger?? iron/steel or aluminum??

look at a Vega....


CASE CLOSED.....


:flash::hissyfit:
 
GTR1999 said:
naasaa said:
I will have to overhaul the rear diff of my 68.
Leaking all over, and expect that the disc's are worn as well.

Where is a good place for spares of good quality?

I haven't open it yet, but both C-clips are broken of the side yoke. Should I expect any damages to the shaft ends?

Lars
Click to expand...

Your 68 is not like the one pictured. If original it has a weaker Eaton posi case with 10-18 spiders or even an open diff. Positraction was an option until 1970.
This doesn't mean it's a bad unit, it can be built to handle up to 1000 hp if needed. Look over the threads I have posted here to help you.

Either Mike or I can supply you with the parts will use. DO NOT get sucked into some of the hype on the web, look over some other threads on diffs here to see what I mean!
Click to expand...

Thanks for your reply GTR1999

My rear diff is stamped AO, so I asume its with positrac.
I'm building a moderate 383 stroker engine so the rear should handle about 450lbft.
Based on your reply I asume that it should not be a problem.

I will appreciate if you can assist with parts when I got it opened and inspected.

Thanks
Lars
 
Lars,
Glad to help once you get into it just let me know.

I would not build a stock differential. Think about what you're going to do with the car. 450 hp is about the limit of a stock diff in an abusive or race use car. Shock loading will break them. I build them several ways depending on application.

"AO" shows as a 370 posi in my book. If you still have the 68 posi then you're really going to want to check it for cracks and polish inside and out. think about those 10-18 spiders as well. They're work but are not as strong as the 10-17's or 10-17 heat treated ones.
 
You must log in or register to reply here.

Latest posts

Back
Top