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A few winter Jobs

Antz81

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I think I'll just change the yoke if needed. I don't like the idea of the zerk fittings in them, all i ever hear about them is they are weaker.
Is it worth using the existing gears? Or just get new ones?
 

GTR1999

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The gears of the used iron or Dana? The parts are not interchangeable between the two. If you find a good iron core you can check the gear lash and pattern to see how it looks. That is what will be your guideline to setting them up. The gears are good and you do a basic rebuild then you probably won't have to change the pinion shim, just adjust the lash to 006-008 with the used gears.
 

Antz81

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The gears of the used iron or Dana? The parts are not interchangeable between the two. If you find a good iron core you can check the gear lash and pattern to see how it looks. That is what will be your guideline to setting them up. The gears are good and you do a basic rebuild then you probably won't have to change the pinion shim, just adjust the lash to 006-008 with the used gears.

I was meaning the iron gears.
Even if they could be swapped between the two I wouldn't use the old dana gears in the iron diff.
 

Antz81

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Spoke to the local guy today, he has one with 3.08 gears in it that sounds like it doesn't need any work. (he said it has new seals as it is his spare for his race car) the Diff and bracket would be NZ$950+tax (15%). By the time the other required parts are added i'm up to around NZ$3100 (tax included). I don't think I can justify this with a stock engine (as much as the stronger diff would be nice). If I try to get them out of the US I think it will be more.
So I might just look at rebuilding the Dana, but with a few mods to make it stronger. This will depend on a few things though.
I did notice today when cleaning the batwing that the seemed to be a few marks where it looks like something has been thrown into the cover by the ring gear. I'll look closer at the gear tomorrow to check for any signs of damage.
 

GTR1999

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Spoke to the local guy today, he has one with 3.08 gears in it that sounds like it doesn't need any work. (he said it has new seals as it is his spare for his race car) the Diff and bracket would be NZ$950+tax (15%). By the time the other required parts are added i'm up to around NZ$3100 (tax included). I don't think I can justify this with a stock engine (as much as the stronger diff would be nice). If I try to get them out of the US I think it will be more.
So I might just look at rebuilding the Dana, but with a few mods to make it stronger. This will depend on a few things though.
I did notice today when cleaning the batwing that the seemed to be a few marks where it looks like something has been thrown into the cover by the ring gear. I'll look closer at the gear tomorrow to check for any signs of damage.

I don't know how the currency exchange rates based on your price. However if you were to look at that iron diff make sure to take the cover off and look closely inside. New seals won't resolve the inherent issues or poor assembly work. A crated diff here is about 135 lbs, give or take. Used value is $400 so it would depend on shipping and custom tax if it's worth it to you. I know it's a hassle to rebuild these cars outside the usa but we have the same issue with some older imports here, although we probably have a lot more resources.

Good luck with it, you know my feelings on using the Dana. They can be rebuilt although I don't think it's worth it.
 

GTR1999

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I dug up some pictures of one of these- before I threw it in the scrap barrel. I would feel dishonest if I took these in and told someone they were built the same standard of my iron units. I have turned them down with some offering a much higher rate for them. Good luck.

on the stand, cover off

Rebuilt80diff4_zps0d330e5b.jpg



Axles
LampRaxles2_zpsa6927f34.jpg


Aluminum bearing cap
LHcap1_zps722f3044.jpg



Case shims are under the bearing- that is pressed on. You will need setup bearings
lashshimsunderbearing_zps80df67fd.jpg



Pinion seal- not the same as the irons

Pinionseal_zps962f3e3f.jpg



Pinion design no crush sleeve, shims used, same square shoulder that failed in the past

Pinionsqedgeusedwithshims1_zps97b159f0.jpg

Pinionsqedgeusedwithshims2_zps3be93016.jpg


Here is the same design out of a 64- snapped in 1/2 in use- driving down the road.
pinionyoke-NG.jpg


Clutch retainer that was ready to shear- like yours
crackedRHretainers3_zps8d788cc2.jpg


Clutches - smaller then the Eatons
clutch_zps028f58a0.jpg


Spiders are smaller too here is one next to the iron 17 side gear
Dana16ampEaton17toothsidegears1_zps06263663.jpg

Dana16ampEaton17toothsidegears2_zpsaafc6169.jpg
 

Hib Halverson

Technical Writer for Internet & Print Media
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71 04 12 19
me, I wouldn't spend a dime or minute on your aluminum diff. I would get a 72-79 iron diff, 1/2 shafts, and brackets. Build that and bolt it to your batwing. It will be stronger then any 80-82 diff.

GTR1999 gets the Monday morning "Beacon of Reality Award".

Those early D44 aluminum-case aluminum drive axles were POSes. Take Gary's advice and retrofit the iron-case GM rear drive unit.
 

Antz81

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936
Location
Auckland, New Zealand
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1981 4 speed
I don't know how the currency exchange rates based on your price. However if you were to look at that iron diff make sure to take the cover off and look closely inside. New seals won't resolve the inherent issues or poor assembly work. A crated diff here is about 135 lbs, give or take. Used value is $400 so it would depend on shipping and custom tax if it's worth it to you. I know it's a hassle to rebuild these cars outside the usa but we have the same issue with some older imports here, although we probably have a lot more resources.

Good luck with it, you know my feelings on using the Dana. They can be rebuilt although I don't think it's worth it.

Just did an estimate, total to import one would be around $920. Doesn't include freight to LA where it would ship from. There may be a charge or two I have missed as well.

As i said I'll need to have a good look at some of my parts and see what is reusable. So far I'll be needed a new carrier, clutch pack, bearings, seals. Plus I'll also replace all u joints and change to adjustable strut rods. It will all depend on price difference. If the difference $1k or less I'll go for the iron diff, it is what I would prefer to use.
 

Antz81

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1981 4 speed
Checked my parts.
Ring and pinion gears have burrs on the edges.
Bearing caps appear to have some cracks forming.
Re usable parts are front yoke, spider gears (maybe i only had a quick look at them) side yokes (maybe)
If I'm right the housing needs to be matched to the bearing caps so can't be reused.
So most of the diff is ready for the scrap bin. The rest may as well follow.
Iron diff will be going in.
 

bill81vette

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Troy,NY
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1981 dark blue metallic
How many miles are on your Vette???

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Antz81

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Auckland, New Zealand
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1981 4 speed
How many miles are on your Vette???

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I believe it's on 105000. The original front rotors were still rivited to the hubs before I replaced them.

I had a closer look at the bearing caps, it's not a crack just a production mark i think. So the housing and caps may be reusable. I'm still going to stick the iron diff in though.
 

bill81vette

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Curious,Did you have any idea anything was wrong with it???
After seeing you apart I am curious if it made any noises...

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Antz81

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Auckland, New Zealand
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1981 4 speed
Curious,Did you have any idea anything was wrong with it???
After seeing you apart I am curious if it made any noises...

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It did make the typical chatter noise about 8 months ago, but that went away after a sucking out the oil and replacing it.
One other thing that bothers me with it, when i was taking it apart there was no need to spread the housing to remove the carrier. I just undid the bearing caps and lifted it out.
 

GTR1999

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A little trick if you do the iron swap- buy some Nordlock washers and use Loctite on the cover bolts. Different rates of expansion between the aluminum cover and iron housing will cause the cover bolts to loosen if you just bolt it in place. You can get Nordlock washer from McMaster Carr or one of your suppliers.
 

GTR1999

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Since you go to CF, look up Mark aka known as Rudolph Schenker. I built him an iron diff for his immaculate 82 about 9-10 years ago. He can give you some installation tips from his own experience. Tell him I said hi.
 

bill81vette

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Gary,are you going to Carlisle????

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GTR1999

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Gary,are you going to Carlisle????

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Hi Bill,
No I will not be going to Carlisle next month, my first missed year since 1998. So that means no 2-3 hour seminar this year either.
 

bill81vette

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Oh well . sorry I'll be missing you!

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Antz81

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Dec 21, 2013
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936
Location
Auckland, New Zealand
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1981 4 speed
The iron diff is finally on its way. The local guy was waiting on the half shafts to arrive before he sent everything. I should have it tomorrow, but may not get to look at it until Thursday. Hopefully since it was the spare for his race car I can just go ahead and install it, but I'll give it a look over first. Maybe upload some pics for Gary to review and give his opinion on.
 

Antz81

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Dec 21, 2013
Messages
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Location
Auckland, New Zealand
Corvette
1981 4 speed
Got to have a look at the diff today It does look like the tear drop design with the 10-17 spiders. gear ratio is 3.08.
My first impression is that this is a much better diff than the dana.
I'm unsure about the clutch pack, it's not the solid clutch pack but to me it looks like it may have been replaced at some point. It also looks like the pinion has been rubbing against the carrier, but I did stick some marking paint onto it and it's not rubbing now, so may have been rebuild since then. 20170809_163641.jpg20170810_154125.jpg20170810_154141.jpg20170810_154115.jpg
 

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