Hi guys, first post! I could use some help. I have a 84, but there is so much 4th gen things on my car I'm a little confused on what I have. It's an open non posi 10 bolt with disc brakes. It's 10.5 tall and 9.5 wide from the one end of the cover to the other. It looks totally different than the rear end on my 92 RS, but I think it's just traction bars thats throwing me off. I was going to check the fluid in it today but instead of a plug there was a plastic cap covering what felt like a giant grease insert.

1. How do I check the fluid or even fill it?
2. Do you guys think it's a standard 7.5? With the T56 the gears are way apart like it could be 3.23 or even 3.08! Way different than the 3.42 and T5 I'm use to.

 

http://www.ringpinion.com/b2c/DiffLi...=Diff&TypeID=5

Don't guess at the gears. Change the fluid instead; and count the teeth while you've got the cover off draining it.

 

ring gear is stamped with ring nd pinoun amount of teeth, no need to count

 

Is it a 10 bolt or is it the 9 bolt Borg-Warner rear end?

 

Check the 10-Bolt FAQ sticky at the top of the page.

JamesC

 

Im not worried about the gears yet, but I also dont want to take the cover off if I cant add more fluid.

Further more, I checked the sticky 3 or 4 times now, I'll measure the axles in the next few days. It is a 10 bolt, thats why I dont understand why there's a grease insert. Those only came on the 9 bolts! Its so hard to see too lol

Just to add it might not be a 3rd gen part because my car has; LT1, T56, 4th gen column and somehow different dash... which I could only imagine would be 4th gen hahah

 

There isn't.

These issues are all addressed in the sticky. Please reread.

Best of luck,

JamesC

 

Can you post a picture of the cover? I'd like to see this insert.

 

Sounds like a 9 bolt

 

I should have labeled the thread different. What ever plug is, its really hatd to get to. Is kinda why I was asking how I could add diff fluid. Since its not a 1/2-14x39/64. GM 25522466.... And the only other plug Ive read about was something along a grease insert, I thought it was that. I know I can, ...in fact.. add fluid lol I just dont wanna mess it up. But I'll take my wishes of luck and be on my way.

 

Can you post a picture of it? The whole rear, the cover, the plug?

A picture is worth a thousand words, you know.

Have you cleaned the axle tube and got the numbers/codes off it? It will be on the pass. side axle tube, on the side towards transmission.. It will be a code with a letter, 2 numbers, a space and 4 numbers and a letter.

The Letter & 2 numbers are the gear ratio code, The next 4 numbers are month and day, then the Letter is the plant code.

 

Just thought of this... Maybe you have the 'rare' Dana 44 rear. IIRC some of those had the plastic plug looking thing in the cover, and they have 10 cover bolts as well.

 

Yes, it has a square drive plug:


Dana44:
dana.jpg?t=1304654858

 

I'm thinking he's thinking, the plastic vent tube on top is the fluid fill.

Which of course, its not... the fill in a 10-bolt is on the pass side at the front of the round part of the pumpkin before it narrows down to the "snout" for the pinion, about halfway up.

So, original poster, when you went to the page I linked you to and compared your cover shape to all those, did it match any of em? That casting number you posted (that's what it is... just, the casting number of the big chunk of cast-iron in the middle of the housing) sure does sound like yerbasic 7.5" 10-bolt.

 

My apologies James, you were right. It is a vent tube. It cant be a grease insert. I tried to get a picture but it never comes out. The vent tube is on the passenger side though. I havent felt a plug that mates to an rachet though. Should I be looking on the other side of the diff for the plug? If I can find the plug to add more, I could pull the cover off and maybe use my dial calipers to measure it.

 

Pretty eeeezy to spot.

 

The plug is on the right side of the center casting in front of the axle tube. Use a screwdriver to dig the dirt off of it.

 

Can I delete this? I just found that plug. Its under the passenger side axle.

 

Nah; won't hurt anything; just add more fluid now that you know where.

 

Yep, just a std. 7.5"/7.625" 10 bolt. The fill plug is on the pass side. On the chunk close to where axle tube goes in at.

No drain on these, to drain you remove cover.

Stick your pinky in the fill hole and bend it down, if you can touch gear oil it's full. If you can't touch the oil it needs more.