Hi , is there any number or letter code to see if the rear axle is
antispin or conventional differential ?

1965 Olds 98.

 

Yes. There should be a two letter code on the right axle tube on the forward side, about in the middle. Probably Q something. QK, for example.

Also, please make new thread for new question.

 

IF you have the car with back tires off the ground safely , on jack stands , in neutral (not running)
Spin a tire , if the opposite side tire spins in the same direction usually indicates posi / anti spin
Otherwise pull the cover and see if there is a clutch type carrier. If so add posi lubricant additive


If axle has had work done .. welded up or posi added axle stamp codes NO Longer have any relevance to how it is now

 

Did you put limited slip additive in along with the oil? If not then you wouldn’t have potentially helped the problem. The limited slip differential needs the additive to allow the clutches to “slip” smoothly. IF the additive has been added or once it is added it will take some driving (especially turning) before the chatter/clunking MIGHT subside.

 

From the factory...IF YOUR CAR IS REALLY original ...you would have had a LIMITED SLIP DIFFERENTIAL FLUID TAG ON THE REAR COVER...OR CHEVY WOULD HAVE HAD ON IN THE FILL PLUG AREA. oops caps key again sorry. Jim

 

Based on the pictures.... it is a limited slip.

Now if the wrong oil was used, it may still chatter for a while after changing the fluid until the new fluid has a chance to penetrate.
Try doing some figure 8's in a parking lot to help work the new fluid in the clutches.

Also you can get a limited slip additive, which is a small bottle (about 6-7 ounces) & add to the fluid. This helps with the irregrular feel (& possible noise) when turning at low speeds.
The GM additive is very good, but may be hard to find in your area.

 

Sorry for that ,should think about this next time

Jacked up the car and spin a wheel , and the other wheel turned the opposite direction .
Thank,s should change the oil and check level.

 

Not sure what series my 1965 98 are ? Series 38 ?
Was thinking change differenttial oil.

 

If you jack it up and both wheels turn in the same direction when spinning the tire by hand, you need a 90wt with a posi lubricant included in the oil. If one wheel turns or they turn in opposite directions, plain old 90wt gear oil will suffice.

 

No. The "3" just means Oldsmobile division. The series number is the second two digits. You have a '98 convertible. That falls into the row labeled 38400. The series is thus 84. The 00 is determined by the body style. By long convention, Oldsmobile convertibles are style 67, so yours is 38467 as shown in the third column.

All '65 98s except the Luxury Sedan are series 84. The Luxury Sedan is series 86.

 

Thanks for info. Have jacked up the car and when spinning one wheel the oppsite goes
the other direction so plain transmission oil will be great.

Thanks for info about the Oldsmobile series codes , have wonder about this for a while.
So my 65 Dynamic 88 should be series 56 with body style no 69 then.
And since my 98 have series code 84 the diffential should have about 4 - 3/4 pts oil.

 

Not transmission fluid, you want 90wt gear oil. I fill the differential until I can put 1 knuckle or tip of my index finger in the fill hole bent down and feel the fluid. I don't fill until it runs out.

 

Sorry language problem 80/90 w approved with MIL-L-2105 B as manual says

 

That will work.

 

Yes, if it's a four-door with center pillars. For many years, Olds called that style "celebrity" sedan and used it the name across the range of models (A, B, and C body cars). If it's a four-door without a center pillar (a hardtop), then it would be a "Holiday" sedan, and the car would be 35639. Olds used "Holiday" to refer to hardtops (two or four-door) for many years as well.

 

Yes it´s a four door with centerpillars.

 

Very nice. Photos are everything on this site. Without them, the cars people claim to own don't really exist!

 

Removed the differential cover today and there was real black
oil in it. But "of course" i got wrong gasket ? .12 holes instead of
10 as i have.( Felpro RDS 55029 ? Took a picture of the differential:

 

I moved your posts from the other thread to this one. No need to ask the same question in multiple places. Yes, that is an open rear end so all you need is 80/90wt with no posi additive.

 

Yes, love to se pictures of cars and parts

Thanks , i agree thats better. Was stupid of me posting in a another thread in the first place.