1964 changing factory installed oil in rear differential

[stevetheweave1]

I pulled fill plug In differential and oil coming out was so thick it looked like growing stalagtite. My vacuum oil remover would not even remove any of it. Yes I realize it is winter but temperature was 55° today and rear end was not cold soaked. I have used 500 weight oil in my wife’s model a pick up truck steering box but this was far thicker than that. If I ever do get oil out should I put 80/90 weight oil back in or I saw another recommendation of using hypoid oil which is what I use in my outboard motor lower unit. Rock auto listed a friction modifier for the rear end oil, I do not think it is needed because there are no clutches and I am I right? Thanks stay vigilant.

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[biddle]

Thanks for adding your model year to your subject! No need to add "Thunderbird" "Tbird" etc, since we are an all Thunderbird site. Thanks for posting. Subject edited/shortened.

 

[74 Harley]

If I remember correctly it's 85W-90. Friction modifier not needed. If it looks that bad you may want to pull the carrier and clean it out real good. May also be a good time to replace the pinion seal and check the universal joints. When doing a major rear end service I do these and the rear seal on the trans. It's not expensive and eliminates several potential headaches all at once.

 

[stevetheweave1]

Thanks Harley tranny is out having all new seals and o ring seals replaced. U joints are good but grease is dried out, new ones are sitting on the bench. I have rebuilt 3 GM rear ends but pulling pinion seal looks a little intimidating (crush washer and bearing preload) especially since it’s not leaking now, but that might be a different story when thinner oil is installed. Have a joyous week.

 

[BigClay]

The only proper way to do this is to pull the center section from the axle housing. Even then, it all won’t drain because of the lip on the housing. I bought my ‘64 in 2015 and I am the second owner. My fluid was so thick (original) that it had dinosaur bones in it! You will have to scoop out the remaining fluid. I recommend flushing the housing with gasoline or solvent and letting it dry. Of course, to remove center, you will have to pull the axles, so cleaning will be easier as you could blow air through the housing from the ends.

 

[BigClay]

The only proper way to do this is to pull the center section from the axle housing. Even then, it all won’t drain because of the lip on the housing. I bought my ‘64 in 2015 and I am the second owner. My fluid was so thick (original) that it had dinosaur bones in it! You will have to scoop out the remaining fluid. I recommend flushing the housing with gasoline or solvent and letting it dry. Of course, to remove center, you will have to pull the axles, so cleaning will be easier as you could blow air through the housing from the ends.

P.S. A very good time to replace ALL seals!

 

[lvhdude]

I case you haven't yet done the pinion seal, it can be tricky to get it replaced without changing the pinion preload. If you carefully mark the nut to pinion location, and the yoke to pinion, you can remove and replace those parts without making a change to how much crush in on the collapsable sleeve. I know they say to replace the nut but you then lose the ability to put it back exactly where it came off. Blue loctite is your friend here. Mark carefully, and put things back the same, and you should be fine.

 

[Douglemmo]

I case you haven't yet done the pinion seal, it can be tricky to get it replaced without changing the pinion preload. If you carefully mark the nut to pinion location, and the yoke to pinion, you can remove and replace those parts without making a change to how much crush in on the collapsable sleeve. I know they say to replace the nut but you then lose the ability to put it back exactly where it came off. Blue loctite is your friend here. Mark carefully, and put things back the same, and you should be fine.

I just changed the pinion seal on my 57 without removing the pinion gear. There are U-tube videos on this subject. Removing the nut so that the pinion yoke can be removed was very difficult. I cleaned the threads and soaked them for a few days and used a 1/2 breaker bar with a 3 foot cheater - wouldn't move. I used the cars emergency brake and a 24" pipe wrench (with a cheater) to keep the yoke from turning. I finally resorted to an impact gun which spun the nut right off. I would use the gun to begin with if I had to do this job again. Before loosening the nut, I counted the threads and measured from the end of the pinion shaft to the top of the nut AND, with the tires removed used a inch-pound torque wrench to measure the preload on the rear end, by turning the pinion with the inch-pound torque wrench. It came out to be 15 inch-pounds. I used a new nut (because I had already bought it when I bought the seal) so it was fortunate that I did the torque measurement because I found that the new Ford lock nut is "taller" than the old nut by 0.200 inches. Interestingly, .200" was exactly the difference in height of the new vs. the old nut. Upon reassembly, I torqued the nut to 100 ft-lb and measured the pre load which came out to 16 in-pounds. Close enough. It is suggested that one starts torqueing the nut and measuring the pre load so that you don't overtighten the nut and distort the spacer that sets the preload.

Good Luck
Doug

 

[1rmisner]

I pulled fill plug In differential and oil coming out was so thick it looked like growing stalagtite. My vacuum oil remover would not even remove any of it. Yes I realize it is winter but temperature was 55° today and rear end was not cold soaked. I have used 500 weight oil in my wife’s model a pick up truck steering box but this was far thicker than that. If I ever do get oil out should I put 80/90 weight oil back in or I saw another recommendation of using hypoid oil which is what I use in my outboard motor lower unit. Rock auto listed a friction modifier for the rear end oil, I do not think it is needed because there are no clutches and I am I right? Thanks stay vigilant.

try useing a heat gun to get it up to about 144 or so. I myself would pull axles out and then pull the nine inch diff out. then you can get in there and scoop all the guu out and while your in there replace axle bearings and pinon seal also. I then replace all parts and add summit read diff oil. this stumm is good. all the pros use it and it keeps the heat down. my diff runs about 140 degrees at most and no noies.