The differential can be installed in your friend's '40 but it will require some modification.
You'll need to determine just what it came from first. My guess? A later model, perhaps post war. If later, the axles are probably longer than the '40 axles.
Have you removed the torque tube as yet? Axle housings?
Mike "Kube" Kubarth
Thanks for the info - didn't know that a 3.54 was not available on '40 Fords. My advice to him was to remove the torque tube and drive shaft on the 3.54 unit and swap them with the torque tube and shaft currently in the truck. What other modifications can you think of need to be done to make everything fit up right? As always, appreciate your precise and helpful information!
Oops, forgot to respond to your other questions. No, we haven't removed any of the axle housings or torque tube from the donor unit as yet. I think you're correct about being a later axle assembly since the torque tube is 3" longer and the radius rods being a different length. Another thing that threw me was the fact that the brake backing plates have the 2 lower brake shoe adjustment bolts. I thought that ended with '40 passenger cars. Please advise.
Tom
Thanks for your comment. I sure didn't know that about the Mercury having a pressed-on pinion gear. Looks like we may have hit a brick wall on this swap.
Bottom line applies to all Swapmeet finds, and many vendor offerings:
Know what you are looking at by your own research, don't put your faith in what you're told by any seller ...And if you think about it, that's a good plan for all sorts of transactions.
Alan
Not doubting your information here, but just want to make certain about this rear axle before we decide to forget this whole swap idea. I've been looking in the big Green Bible (28-48 Ford parts book) and I can't seem to find any reference to a drive shaft or pinion gear that identifies use specifically for Mercury or a vehicle with 116" wheel base, which is Mercury. It lists the following drive shaft and it's the only thing close that I could find :
68 4605-B Shaft (drive)-solid-use with axle having 6 spline pinion Pass, Comm 37-41
Were ALL Mercury driveshafts one piece with a pressed-on pinion gear? Is there even a remote possibility that it just might have a splined collar like Ford used? We would have to remove the torque tube to verify. Again, not casting doubt on your information, but just would like to confirm, if nothing else but to expand my own education!
If you have any further corroboration it would surely be appreciated.
As I said in my previous post, MOST 39-40 Mercury drive shafts have the pinion gear pressed on the drive shaft. I have never seen one that wasn't, but some people have claimed they have seen them with the splined drive shaft. With Ford manufactured parts, I never say ALWAYS or NEVER, because someone out there has an exception.
The 39-48 Mercury parts catalog lists the gear set as "99A-4209A Ring gear and drive shaft with pinion, matched set 3.54 to one ratio."
My identification of the rear end is just a guess. There may be other drive shafts other than 39-40 Mercury ones that are longer than the stock Ford, I just don't know of any.
Pulling the torque tube is not a big job, so you could do that and verify if it is a Mercury rear end.
Tom
I'm very interested in getting more of an education on this topic, and hope you could shed some light on something for me. You mentioned above that the 3.54 ratio was NOT offered for the '40 Ford. I noticed in the Green FORD parts book there is a listing for a 3.54 ratio ring & pinion (48 4209-E) and states that it fits '38-'48 Passenger & '38-'41 Commercial vehicles. Taking your statement into account, how should we laymen interpret that? Given the fact that there is a listing for the part in the catalog, was it available perhaps as a replacement part if someone wanted to have it installed it in their '40 Ford instead of what came in it? Was it possible to special order a '40 Ford passenger car with that ratio? Is it listed there for some other reason? I would really appreciate your thoughts as to why it is there. Don't mean to split hairs, but I find these details fascinating and educational. Maybe it's a sickness!
Thanks for your feedback!
Alan
Yes, I am familiar with Hollander and have one for cars in the '50's & '60's. I also found I had a '46 Ford & Mercury chassis parts catalog that DID show the specific drive shaft with pinion and matching ring gear that TomO referred to in his post above. As he pointed out, the Green Ford catalog didn't specifically point to the Mercury drive shaft. This exercise is certainly giving me a good education into the nuances of using the Ford parts catalogs. Thanks for your perspective.