40 Std Gear ratio
- Thread starter Stdblk40
- Start date
JSeery
Member Emeritus
You would have to define easy. I would not call changing a ring and pinion out "easy" on any rear axle. If you are persistent and enjoy doing that sort of thing it is very doable. There are a lot of folks on the Barn that have rebuilt and/or changed gears in a banjo rear end. Changing the ring and pinion and rebuilding it are about the same thing. Takes some special tools, but you can make them if you have the capability and equipment to do so. You could always change the whole rear end assembly but more likely than not it will also require a rebuild (you would save the price of the ring and pinion, maybe LOL).
If you can find a complete clean 3.78 rear end ( stamped 9-34 on the bottom of the center section) that turns easy and that will be the most economical way. I have had a lot of good luck with rear ends as many have low miles. Have about 6 on hand and pick them up in the $300-$600 range. The 37-40 rear ends will all work for you. Obviously you may need to change brake drums. The biggest problem with the old rear ends is that the axle seals dry out from sitting and age. To change your ratio it will cost you $1500 to buy the parts, new bearings and have someone assemble it. But you will know what you have also. Toss the coin.
I have a warmed up 53 engine. approx 120 hp. If it is a 4:44,,, wow! It does launch out there pretty quick. But at 60 mph it is wound up pretty good. I think a swap would be easier. I can replace seals and related things,I did it on the existing rear end. I think maybe a higher gear than 3:78 I would be happier with. Were there any higher ratios in 37 thru 40? I wanna keep that original Banjo look.
JSeery
Member Emeritus
Not that your going to find laying around. You can buy higher gear ratio ring and pinions, but finding an assembled rear end with a higher gear would be difficult and most likely expensive.
48 coupe
Senior Member
email me
micklfinnell@rpt.coop I have a 3.54 [ long story.]
micklfinnell@rpt.coop I have a 3.54 [ long story.]
alanwoodieman
Well-known member
go to the midwest to look, lots of 3:54 out there, even had a 3:54 in a columbia two speed-that must have flown on the flatlands!
rotorwrench
Well-known member
A swap would be easier but finding a 1937 through 1941 complete rear axle assembly that is ready to go, is a whole different game. If a person has a decent dial indicator set, a relatively well set up press, and a few tools necessary (as was already mentioned), its not too bad a project. They are easier than some of the late model stuff once you get tooled up. There are other threads on rebuilding axles here and on the HAMB.
My Dada has an original 60 hp 40 coupe that he now has a 59A in it. The rear end seems pretty low. We thought 4:11...but it sounds like it is possible to be even lower?
We have a spare rear from a 40 sedan that has the numbers 2A on top then 3.15-37 below. Wondering what ratio this would be?
We have a spare rear from a 40 sedan that has the numbers 2A on top then 3.15-37 below. Wondering what ratio this would be?
Karl Wolf
Well-known member
If what you have is a clean original car, I would think that you'ld be better off putting gears in what you have... Thinking that anything else in the form of a complete rear is likely to have had more wear.
I would try to put in good used original gears- I have heard some where that reduces the likely hood of need for pinion depth adjustment. I did assemble the rear end in my avatar using banjo parts that never saw each other before. It's a bit more work than a simple assembly, if you're lucky and good maybe 2-3 times...
Clearance (backlash) and preload are set using bell to center section gaskets.
I got the technique I like from a "Fix your Ford" old book... If you contact me, I will find it-
Karl
BrianCT
Well-known member
9-37 is 4.11
BrianCT
Well-known member
Go for the 3.54
TomT/Williamsburg
Well-known member
OK - I'm not one to drive completely "stock" vehicles but I can certainly appreciate those who want to remain as such. Here is what I would do ....
IMHO I think the easiest thing to do is to find a banjo center section only with the more realistic-to-find 3:78 gear ratio or may you will get lucky and find a 3:54 all ready installed. No bells, no axles - you already have what you need. That way you can have all of the settings of the center pumpkin checked before you make the swap using your axles and bells and I would install the tallest 16" tires you can fit under the rear fenders. That would bring your RPM down considerably, you have the 4:44 to swap back in to go back to original, your cruising rpm will be much less and no one is the wiser. I would say though that you are probably going to find a 37-38 rear more readily than the 39-40 (that's just what I have found) but that's just from where I live and check out the classifieds/swaps for.
I would check out the swapmeets that cater to older stuff within a 100 mile radius of you and see what you can find. No doubt you can find something at either the Charlotte Spring/Fall Auto Fair, Spring or Fall Carlisle, any AACA swap meet, or Fall Hershey if you know of anyone going to one or more of these events who can and is willing to haul it home for you. I know I have come across several at each of these events.
The whole point is that you could go back to completely stock in a heartbeat with no worries. Good luck and keep us all posted ....
IMHO I think the easiest thing to do is to find a banjo center section only with the more realistic-to-find 3:78 gear ratio or may you will get lucky and find a 3:54 all ready installed. No bells, no axles - you already have what you need. That way you can have all of the settings of the center pumpkin checked before you make the swap using your axles and bells and I would install the tallest 16" tires you can fit under the rear fenders. That would bring your RPM down considerably, you have the 4:44 to swap back in to go back to original, your cruising rpm will be much less and no one is the wiser. I would say though that you are probably going to find a 37-38 rear more readily than the 39-40 (that's just what I have found) but that's just from where I live and check out the classifieds/swaps for.
I would check out the swapmeets that cater to older stuff within a 100 mile radius of you and see what you can find. No doubt you can find something at either the Charlotte Spring/Fall Auto Fair, Spring or Fall Carlisle, any AACA swap meet, or Fall Hershey if you know of anyone going to one or more of these events who can and is willing to haul it home for you. I know I have come across several at each of these events.
The whole point is that you could go back to completely stock in a heartbeat with no worries. Good luck and keep us all posted ....
supereal
Well-known member
When looking at rear ends to swap, always look carefully at the underside of the axle housing ends. If they are badly spalled, keep looking. Unless the rear end has been submerged or run dry, they usually have servicable gear sets, but spalled housings must be disassembled and fitted with good quality sleeves, a job for a good shop.