Technical 3.78 old 34/9 tooth gear

I bought a 37 rear axle ( cheap ) and it shore was rusted, but housing ends ( is it call : struts ? ) is not that bad but water inside but so far its been in hot tank.
I check tooth on ring and its 34 so guess 34/9 is a 3.78.
I will use lemon accid to get away rust on gear/diff but it might go deep.
Will get some pics tomorrow on ring & pinion.
Would this work with nee bearings and thick oil ( this car will not be much used for longer trips )
Still its a std Ford ( no China ) and I cant see any damage.
I will has a LZ 26 tooth ( 2.33 first gear ) and I think 3.78 will be fine ( not over 125 HP my guess )

Ideas here ?
( its not about saving money, ad its just ’here’ but I will not be waste time.

 

Rust pits are places for oil molecules to be stored for additional lubrication.

 

Yes thats one way see it ;-))

 

the other way to see it, is that the pits are reducing the surface area of the gear tooth. This increases the stress on the remaining metal, making it wear faster.

you should not ask a question like this, until you have pictures. Because we all have to guess, until we see it.

 

Here is pictures, pinion has just minor pittings.
Ring is most Ok but see pictures as pittings is here and there.
Good anyway so old and been out for decades maybe.

 

I would not try to use that ring and pinion. It will likely be noisy and wear quickly.

 

Use some crocus cloth on it and run it.... Use 140W gear oil....I would....

 

I have used gears in worse shape than those for daily drivers. I did use graphite powder mixed with the gear oil. It helped with the noise.

 

I wouldn't use it. Think of all the money you will have in the bearings. Too much to waste if the gears start eating themselves and fill the bearings with grindings.

 

I shore could run it but if to noisy its not fun even the small trips I will do.
Some ’trix’ might help and thick oil.
I will look on a other 37 axle this weekend with a 39 complete front axle in a kit.
That did also look rusty and don’t know gear ratio.
The 3.78 look like 400 US new ( plus imports ) if there are on sale.
I might can use a 4.11 aswell.
Anything under 3.78 is not intresting.

 

Doesn't make any difference what ratio you use when you have a quickchange.

If you find a nice 3.54 R&P you can trade it for four nice sets of 4.11's

 

Well, I might has drop the era back 8-10 years on this coupe now.
Most of my stuff is late 30’s.
As I will use std fuel tank the QC would not be seen much and as I bought a good core 38 block ( near a complete engine ) for 100 US last week plus this 37 axle for 40 US I’ll just keep the 36 rear axle/bones and the 59A block, A-Ford cross/spring/clips etc parts I also has for a roadster later on.

So this coupe will be prewar but not mid 30’s style, more very early 40’s.
By not use the QC and Ardun heads ( new of OEM ) I will has some money on the 32 coupe body instead.
I will go std heads but a late 30’s intake.

 

Rust pits are where stress risers occur, stress risers are where CRACKS start! A pit might hold oil ( old nonsense) until the part break's and damage's everything around it. Do some research on metallurgy and parts failure. Think about a high load part like gears.

 

I has no rear end experiance as I do machineworks and enginees but on my racecar 3700 LBS Hemi 700 HP NHRA stocker I use Dana 60 and Pro Gears and 9310 are soft and last forever with a auto trans ( 1.29 60-foot )
Before I did run 383/stick and I has never had gear issues since 1988.

-But this is s time machine and will not be cross county or daily driver, no burn outs but I don’t like be noisy as a old tractor and I dont like blow it.
-That’s why I asked, maybe this stuff works ( as some say ) and I like a Henry part back there and h-e China stuff, but will not go the wrong way.
If so better get a nice Henry R/P 3.78.

 

Agree 100%. Don't use it. It is a royal pain in the arse to break down a rear end once it's in a car. Find a better one. They are out there.

 

I has located up a 'maybe' better rearaxle core.
This one I payed 40 USD for it but still some parts can be used ( or sell it ) and this one today has a 4.11 and it fits me OK and price only 200 USD.
Ok I has not seen inside, but it's rusted outside as my other one, so I can give it a try.
I see Speedway sell 3.78 under 400 USD.
Noisy just as be cheap is not the correct way ( as car will be expensive )

 

Well now that you have a second rearend, you can take a chance with that. Hopefully it is better shape inside.