Whining from the rear axel for '69

[django10000]

Hi all,

I have seen many posts regarding a whining noise from the rear axel when the car is in gear and moving. At this point I have to assume it could be coming from the differential and plan on starting by draining the old fluid and replacing it with new. Any helpful hints on doing this? Also if I jack up the rear of the car to do this and the car is on a slant, how will I know when I have put enough (or too little) fluid in? Is there a specified amount that should go in? The manual was not too clear on this, just says to fill it to just below the fill hole - but that doesn't help if the car is up on one end. Any help would be grateful - thanks.

 

[LVMYVT76]

I would suggest you use 4 jack stands and get the car level to do this. I think you will have to suck the old fluid out through the fill hole since there is not a stcok drain hole(you can drill in a drain hole in the bottom of the diff and thread it for a drain plug). then fill with the chev posi-track additive and diff fluid. I always put in 2 bottles of additive and then filled with the chev diff fluid, others may do it differently. Make sure and break in the fluid by driving circles in a parking lot.

 

[django10000]

Thanks for the response. I just was not sure how necessary it was to put 4 stands under the car, but it makes complete sense to keep the car level. I guess I have to go buy two more stands for my saturday morning project. Thanks again

 

[LVMYVT76]

Its better to have the level and secure to go under it, don't want it to fall on you!

 

[GTR1999]

Level is better for this job but secure is the most important so be safe.
You'll have to use suction to pull out the old oil unless you have a tapped drain hole. I install them when I rebuild the diff's makes it a lot easier to change the oil.
If the posi was hammering then add 2 - 4oz bottles of GM additive and fill the rest with Lucas 85-140 gear oil. when empty an iron diff will hold 60 oz total of oil/additive.
Good luck

Here is a lot of info on diff that may help you understand them as well.

http://www.vettemod.com/forum/forumdisplay.php?f=24

 

[django10000]

This is great - thanks Gary. I'll have a read - still learning how to do my own work on this car. If I get good enough (and confident enough) with working on the car - maybe a lift in the garage may become an option...makes work like this much easier.