okay so i did a lil power brake action on the blacktop and well both tires laid down rubber.......... my car is a 85 delta 88 vin 9 with th2004r (hydra matic) transmission and stock rear end. what's up with that?

 

It happens sometimes. Look at your trunk sticker. G80 is the posi option , and gu1,gu2,gu3 etc. etc is the gear ratio code.

If memory serves me correctly Gu1 is 2.41 gu2 is 2.73 and gu3 is 3.08....I'm Not 100% on the ratio codes though.

 

will do =P thanks

 

okay it's got a posi and it's 2.73 thanks for the numbers!!!!

 

Thanks for the code breakdown J! I have a 85 with 2.73 but looks like no posi

Its time for my differential to be serviced I bought a new chrome cover and fel-pro gasket do I need any sealer or can I just run the gasket bolted down to correct torque spec?

Also I believe the gear oil is 80W-90 each bottle is 1 quart how many do I need? I was guessing 3.

Thanks in advance guys.

 

2 will always be just shy of what you need. So 3 would probably be the correct count even though you will use VERY little out of the third bottle

Chrome cover. Make sure you scuff the chrome from the sealing surface and use sealant ... The chrome is so smooth the fluid will sometime seep past the chrome and sealant. SOMETIMES...

Jim

 

Is it an 8.5" or 7.5" 10-bolt rear?
I've found that a lot of times on the late 70's and 80's GM cars, if the G80 (posi) option was ordered, they put an 8.5" rear in the car that otherwise would have gotten a 7.5". Especially with a 2.73 or 3.08 gear.
Maybe just a move to simplify things on the chassis assembly line?

 

I am really curious about your car as well. I have never seen a delta 88 with an 8.5" rear end after 1980. I have owned 6 of them, and the 80's cars all had 2.41 open 7.5 rears if my memory serves me correctly. The 77 and 78 had the 8.5" rears. 1 was a 2.41 posi, and the other was a 3.08 open that looked to have been replaced at some point.

 

Who added the vin 9 engine also? That is the high output 307, onlt available in the 442/HO those years. It is much more desirable over the std vin Y slug. I wish my '86 had the 9!
Looks like someone really made that Delta the way it should have been built!

 

Use sealer. Also, after filling the diff to the bottom of the filler plug, you might wait 30 min or so for that thick oil to fill all of the nooks and crannies. I filled a diff quickly one time and the next time I checked it it was 1/2 qt low and there were no leaks.

 

I've got an '83 delta 88. Been doing some cleaning up underneath the car, I drained the differential oil today. I was wondering what gear oil to put back in it. would
75w-90 GL-5 work? Does anyone know what the manual calls for?
Thanks guys,

-Rob

 

80W-90 is what my manual says also said the same thing above.

 

Rears are NOT too picky about fluid...lol. JUST be sure you fill it to the correct fill plug level and you will be good to go.

80-90 75-90 85 140

Synthetic, standard mineral base if fine etc.

Good luck and make sure the jack stands are under there. Jim

 

Both of my Deltas were 2.73 open rears with the 7.5 ten bolt.

The 8.5 of the same year were found in the wagons, but as J informed me, the wagon rear with bolt up, but be 2 inches too wide.

91-96 Impala rear will bolt right up, but it's a 5x5 bolt pattern. The 9C1 had the 3.08 G80 unit in it with 30 spline axles. However the 73-77 Cutlass/Monte Carlo rear will also swap right in. They are exactly the same, right down to the brakes (no extra valves needed for rear calipers). They are 28 spline units

 

yea thats pretty cool to see a delta with a vin 9 307 an a good old posi

 

The wagons also use the 5x5 bolt pattern.