View Full Version : Axle and Axle Fluid Question
03-31-2001, 04:08 PM
What are the axles called that came in K-10's that are not posi? It isn't limited slip is it? I thought that limited slip was posi. Anyway, I took a rear end out of a 79 k-10 which is not posi and replaced the posi in my 73. Only one tire gets the power is the best way I can desribe these rear ends. Anyway, I am using Sta-lube Limited SLip HYPOID SAE 80W90 which is API/GL-5 PLUS. This fluid is for posi and limited slip rear ends I think. My question is will this fluid hurt the rear end I have in now since it is not posi? The gear oil is still 80W90 weight so you wouldn't think it could cause any problems. The axle out of the 79 does call for plain 80W90 weight though. SHould I drain the 79 axle and just put normal 80W90 in? Maybe those rear ends are called HYPOID. What's that?
03-31-2001, 09:21 PM
It could be you have a popular feature called "Governor Lock" used in many Chevrolets. Have seen many for sale on EBAY.
I suspect your problem is that either the clutches are burnt out or you need a friction modifier.
Can't hurt to try the modifier first, it's about $5.00, available from Ford, yes Ford,
Ford Motorsport part # M-19546-A 4 oz bottle. I think the stuff is actually made from shark liver, so if you are allergic to fish you need to be careful to make sure you clean up and don't get it on any open cuts on your hands.
If your unit is toast, maybe you can replace the clutches or replace the whole unit. Eaton makes a great limited slip unit which is OEM in many applications.
You may want to call Randy's Ring and Pinion toll free 1-888-231-2493. They are knowledgeable and have reasonable prices.
Best of Luck!
04-01-2001, 12:58 AM
You can also buy the stuff at pep boys or nappa.
They are hard to find, at some automotive places, because they dont carry it in stock.
I have a ford tbird turbo, and the additive is for the clutches. Mostly for limited slip diffs.
It will look like a large toothpaste tube, so they easy to miss.
Well, either I didn't understand your post or the guys up above didn't, but what I think you were saying is you replaced your posi unit with one that is not, and now you have what I like to call, a one wheel wonder. You spin one tire if you spin it. This is called an open differential, and the gear oil with the additive for limited slips (aka, posi's) is just fine. It is made to work with the clutches in this type of differential, and your diff is nothing but gears. It should work fine, and I bet if you read the fine print it will say, works with all differentials requiring 80w90, including limited slips, or something to that nature. Hope that helped.
I'm in agreement with MTCK on this - you've got the regular open diff in there from the sound of it. The gear oil you're using now should be fine. "Hypoid" refers to the style of gears used (shape & the way the teeth are cut)
04-01-2001, 02:45 PM
For snwering what I asked :) I guess my post wasn't totally clear so thx for getting through it.
Garet, you're very welcome. It's always nice to be able to help each other out.
I was just thinking of something while re-reading this post and your one about "4x4 bucking" - is the rear axle that came from the '79 the same ratio as the front axle in the '73 it's in now? It's important that axle ratios and tire size/diameter be the same at both ends of the truck so driveline rpms stay matched. Just a thought. And - what the other guys have posted about possible causes for the "bucking" you're experiencing are all good too. Sometimes it's a combination of different factors.
[Edited by 75 on 04-01-2001 at 02:12 PM]
04-01-2001, 03:14 PM
I took both front and rear out of the 79. I was hoping the rear out of the 79 would match the front in my 73 but luck would have it otherwise.
OK, that's good to hear. It may in fact just be normal for your truck to do that - one thing to keep in mind is that older trucks such as your '73 & my '75 were a lot less "car like" in the ride department than they are now.
But I still like my old one!
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