1941 CAD WORN SPIDER GEAR REAR END HELP NEEDED URGENTLY

[nzcad]

THE SPIDER GEAR SPLINES ON MY 41'S REAR END ARE WORN. SEEMS TO BE A SEALED UNIT. HOW DO I REPAIR THIS OR WHERE CAN I OBTAIN A REPLACEMENT OR REBUILT UNIT??

[Jim Stamper]

     The Shop Manual says replace whole differential with a new factory unit.  I have seen them on Ebay often, but they are a heavy thing to mail far. I think, someone more expert should verify, that you can use 41 and later rear ends. Definitely not 1940 and earlier, different axle splining.
                                                 Jim Stamper CLC#13470
                           

[Steve Passmore]

I'm unfamiliar with the term 'Spider Gear' is that a description used in your country Steve? you will need to be more specific, you have a Crown gear, a Pinion, Planetary gears, and two axle shafts.
As Jim states Cadillac never intended to have these repaired in the field but to replace the whole unit, you can only rebuild these with specialist tools, I have been searching for them for years. It has been talked about many times on this forum.
You posted previously you had excessive side ply? side play where? if you mean in the wheel that does not mean wear in the diff unit, Axle shafts are held in place by their bearing and spacers behind the brake drums, you may have the problems there. Tell us more detail Steve

[TonyZappone #2624]

I have been advertising a complete 41 gear assembly on this forum.  I don't want much for it.  Someone who knows what they are doing would have to look at it.  Icannot ship.

[nzcad]

THANKS FOR REPLIES. THE TERM SPIDER GEAR IS USED IN THE PARTS BOOK BUT I THINK THESE ARE ALSO KNOWN AS PLANETARY GEARS. IT IS THE SPLINES ON THIS GEAR (MATES WITH THE INNER END OF THE AXLE SHAFT) THAT ARE WORN. I HAVE FITTED NEW OUTER AXLE BEARINGS BUT STILL HAVE MOVEMENT ON THE INNER END OF THE AXLE WHERE IT GOES INTO THE SPIDER/PLANETARY GEAR.
TONY...IS THERE SOMEONE UP THERE I COULD GET TO REMOVE THE COMPLETE DIFF HEAD AND AXLES FROM THE REAR AXLE HOUSING TO GET CHEAPER SHIPPING TO NZ??

[TonyZappone #2624]

It is not in the axle housing.  It is just the gear assembly.   I could take it to a UPS store I suppose, I would have to wrap it so the grime would not get all over.  Then the shipper could call you, get a credit card and ship it.

[gary griffin]

I had one shipped to me in a milk bottle carton, the heavy metal one they keep reusing. I did not weigh it but I would guess 70 pounds? 

   What gear ratio do you want? There were 3 different rear ends in early 40's Cads. The higher two were only available with automatic transmissions and the 4:11 was in the three speed standard transmission cars. I am replacing my 4:11 with a higher geared differential and have the 4:11 with 67,000 miles available in Seattle. I have standard transmission but my driving will be mostly highway so I chose a higher ratio. (actually numerically lower but higher speed)

[markl]

Steve,
I see you are in New Zealand, so I understand the concern about shipping costs which could easily exceed the cost of the item at purchase.

Gary,
You make a good point about selecting the desired ratio.  I wonder if you have ever noticed a stamping in the ring gear that ties a certain number(s) to a certain ratio?  My own interest in this issue arises from having a complete differential assemble that was fitted to my 37 LaSalle and was obviously from a later car.  This I'm certain of because it used 5" bolt circle.  But other than that, I haven't a clue as to its year ( original application ), or its ratio.  I realize that if I counted the teeth on the ring gear, and then removed the pinion gear and did the same, the ratio would be obvious.  But I'm hoping that there is a way to figure out the ratio by just removing the cover and finding a stamping somewhere.

Don't mean to hijack Steve's post, but this information should be useful to him in his quest for parts, and to a potential seller for accurately describing what they have available.

Mark Lowery, CLC# 25216

[Jim Stamper]

     Mark and NZCAD;

     Mark, if the back cover on that old rear end is removable there might be something to be learned from that alone since the older rear ends have a welded on back cover.  When was the bolted on inspection cover started?  Does the 41 have the bolted on cover?

     I have three rear ends laying around. At least one of them has the ratio stamped on the ring gear.  Another has the # of teeth of both ring and pinion stamped on the ring gear from which the ratio can be determined.

                                          Jim Stamper  CLC# 13470

[tozerco]

Kiwi,

I have no idea whether or not the owner wants to part it out for you but I sold a complete '38 rear end to a gent in Melbourne last year (for much less than it cost me to get it here, actually). He has a couple of '38's and I suspect he bought it because he thought he might need a spare some time. I can contact him for you this weekend and see whether or not he will part with the bits you need. Would be WAAAAAAY cheaper than trying to land a diff centre from the US. Done that too and I'm still paying it off!

Let me know if this is of interest but it would be up to him to decide to to sell/give you the bits.

Regards

[Jim Stamper]

     The 41 axle splines will not work in the 38 differential, and the 38 rear end itself is narrower than the 41, I believe.  No joy here even if he will sell it.
                                     Jim Stamper CLC#13470

[nzcad]

THANKS FOR ALL OF THE IDEAS AND HELP. FURTHER CHECKING SHOWS THAT THE SPIDER GEARS (PLANETARY GEARS) ARE A BIT LOOSE IN THE DIFF HEAD AND ARE CAUSING THE MOVEMENT. MY DIFF HAS THE 3.36 RATIO (47/14) AND I WOULD LIKE TO RETAIN THIS GIVEN IT IS A HYDRAMATIC. TONY...COULD YOU PLEASE CHECK THE RATIO ON YOUR DIFF HEAD BY COUNTING THE TEETH ON EACH OF THE CROWN WHEEL AND PINION. ALSO I THINK YOU CAN PUT YOUR HAND INSIDE THE SPIDER GEARS AND CHECK WHETHER THEY ARE FIRM IN THE DIFF HEAD OR ARE A BIT LOOSE LIKE MINE.

[TonyZappone #2624]

Steve:  I can do these things for you.   However, when I uncovered this thing, it is huge.  I might suggest you contact Steve Cooley on the other side of Florida, he specializes in '41 and later flathead stuff.  He might be able to get you just those elements you need.  I can't imagine what it would cost to ship this monster to New Zealand.  Tony 

[Steve Passmore]

I agree with Tony, I had a complete axle shipped to the UK from the US and UPS wanted £1500 ($2250) bearing in mind the diff is the heaviest part.

[Jay Friedman]

Steve,

All 41 to 56 differential assemblies (not the whole axle housing) are interchangeable.  The only differences are the gear ratios.  However, the shop manuals say you cannot take one apart and replace any faulty components, with the exception of the pinion seal and the pinion bearing.  You must replace the differential assembly if any other component is faulty.  According to an expert friend of mine the reason is that certain internal components are held together by special pins which must be destroyed to disassemble the unit.  It then can't be put back together.

The 3.36 ratio differential assembly is the most common as it was used on most Series 60, 61 , 62 and 63 cars with Hydramatic, the largest selling Cadillac during the period.  You can usually tell if a unit is this ratio without having to count the teeth because a number 6 should be stamped on the outer case just below the pinion bearing/seal area.  (Other ratios have different numbers.)

I recently sent a spare differential to from my home in Georgia to Pennsylvania (600 miles) where it was installed in a '49.  I took it to a UPS store where they packed it in a special box they made up from several layers of thick cardboard and syrofoam.  When packed it weighed 75 pounds (34 kilos) and was a cube of about 24 inches.  The cost was $35 to pack it and $80 to ship.  It arrived safely.

Email me separately at jaysfriedman@yahoo.com as I'm in touch with a guy in Christchurch NZ who has imported cars and parts from the USA to New Zealand and who may have some suggestions for shipping. 

Jay

[Jeff Maltby 4194]

I shipped a 49 pumpkin to Thomas in Denmark 4 years ago. I made a wood box to fit snugly, then wrapped plumbers metal pipe banding around it, screwing it down. I left one band long enough to form a handle, then used an old motorcycle rubber handlebar grip secured with duct tape .

If you ship it any distance to a shipping port on the west coast, Greyhound is the cheapest way to get it there as long as it doesn't weight over 99 lbs. 

[Jay Friedman]

Jeff in California calls it a "pumpkin"; here in Georgia they're called a "chunk"; in my youth in New York they were a "diff".  In Cadillac parts books it's called the Differential and Carrier Assembly. 

[Jim Stamper]

     In my California drag racing automotive youth in California in the 1960s, we called them "third members". I destroyed and replaced quite a number of them.
                                Jim Stamper; CLC#13470

[Steve Passmore]

True name here in the UK is Differential or 'Diff' but Ive often heard old mechanics call it 'The Pig'

[nzcad]

Interesting to see that none of the names for the diff are complimentary!!
Tony....I have a shipping agent contact in LA who would arrange pick up from your home and send it back to NZ as part of a container load he ships to NZ regularly. An other option is that a NZ friend is hoping to buy a car currently listed on ebay and we could bring the diff back with the car at no extra cost except getting to where the car is (if he wins the bidding).
All I need to know right now is what ratio the diff is and whether the spider gears have play where they attach to the diff head. Also I need to know what price you are looking for. My email is stevetrott@xtra.co.nz if you prefer to advise price offline.

Thanks Steve