63 Differential Rebuild Parts

[Joseph S.]

Having disassembled and cleaned my 63 differential, all carrier and gears look to be excellent shape. Am now looking to rebuild with new seals and bearings. Paragon lists a kit for the later Eaton differential ('65-'79) and Corvette Central lists a 66-79 kit with a note in the description that the small crush sleeve must be ordered for earlier (63-65) units .
Neither supplier's tech people could tell me if the carrier and pinion bearings/seals interchange between the early (Borg Warner?) and later Eaton units.
My question; do the bearings and seals interchange between a Eaton(65-79)and and earlier, 63-64 differentials and if so, is the only difference the crush sleeve for a basic (not including gears and carrier) rebuild? Can anyone recommend a good supplier for the bearings and seals?

[Joe R.]

Re: 63 Differential Rebuild Parts

Joe,

The Eaton is your best bet as it will interchange in your housing and will live longer than the Dana you presently have. Gary Ramadei is the resident rear end builder on this forum and can answer all your questions regarding rebuilds. Contact him thru this forum as he usually answers all questions regarding rear ends.

Joe Ray

PS. At the bottom of this thread there are similar threads that may help you identify interchangeable parts.

[Gary R.]

Re: 63 Differential Rebuild Parts

Hi Joe & Joe,

Joe S, I sent you some information but for the benefit of others with 63-64 original posi diff's I will go through the diff and the issues with it. Hopefully it helps some of you. This is type of thing I discuss in my seminars.

While the 63 and 64 vettes were/are impressive cars the optional posi traction was in fact a weak link. Many of them have been rebuilt or the whole diff replaced with another year diff.

These were made by DANA and use the same bearings and seals as all 63-79's used, the bearings in fact are the same as the 12 bolts used. Sourcing the bearings is as easy as writing down the Hyatt part number and visiting your local bearing supply house for USA made Timkens or a parts store- although you may find none Timkens offered. I like and use only the USA Timkens. The seals are the same as well and while the kit axle seals are ok I still like to use a CR/SKF pinion seal.

So what is the issue with the 63-64's that some won't rebuild them or kits don't list them?

1- The kits are sold and setup for 67-79 differentials. The side shims used for the 63-66 narrow housing are not included in them. They won't tell you that and I have seen many guys screw up the backlash and pattern because of this. They were a steel shim between 064-095", they were sold in "kit" packs from GM, I bet Joe L has some. I stocked up years ago on them or machine up my own. Yet they are sold today and you are not told, why is that?

2- The DANA posi are obsolete. They were very weak and often broke in 1/2 so if you were able to find a NOS posi clutch kit from 50 years ago why use it?

3- The pinion design with what I call the wedding band crush sleeve, is terrible. It was a weak point that led to them snapping in 1/2 at the shoulder. They had a 17 spline count so the pinion yoke will not fit the revised pinion design from 1965 which has 30 splines. They were all 1310 yokes with u-bolts with the exception of the original 63 Gran Sport diff I built that had a 1310 bolt and strap yoke. Never saw that before and I don't know if it was used on other lines- maybe Joe or Tom Parsons would know?

So if you ask for my advice on whether I would recommend rebuilding an original 63-4 diff with a bearing kit the answer is no. Maybe an open diff but you still have the weak pinion gear.

If the car is going to be driven, maybe not as hard as they once were, I still wouldn't use one. Rolling on and off a trailer, ok you should be good.

I just built a 64 diff, the clutches were falling out when I drained the oil. The complete posi, pinion yoke and R&P went into the scrap barrel, those who may want them can call Albert Bros scrap metal in Waterbury CT as that is where they ended up. I ended up using a NOS usa made Eaton 3 series case, Toms usa made 373 gears and 10-17 x17 usa made spiders- not the current offerings by the way. This diff will hold up to 450hp all day long. The original axles were as good as they day they were installed in 1964 and BETTER then what is offered as new or rebuilt today.

Here are some pictures for those of you interested. I am not going to Carlisle this year so no sorry no seminar. These are before and after. You will notice the NOS Eaton is fully polished and tuned- no springs or plates used or needed if correctly setup.

[Gary R.]

Re: 63 Differential Rebuild Parts

One thing to note these are 2 different original 1964 diff's the one odd thing, the rebuilt one has the tabbed bearing caps, the before one doesn't as most of the 64's had. 63's have wider caps with tabs. The tabs showed up in 71 again. I don't recall ever seeing tabbed caps in a 64 before and this was 100% original. I have no answer for that.