The Stovebolt Site Forums The Shop Area Driveline 3.55: 1 Ring-and-Pinion Swap for my 1946 chevy AK 1/2 ton

Hi, I would like to purchase a 3.55:1 Ring-and-Pinion Swap kit to mount on my 1946 Chevrolet 3100, AK series 1/2 ton.
I only found one supplier in the UNITED STATES, I think there are others......
do you have a lead?
thanks in advance
sorry for the translation ......

C'est un beau camion.

Chevy's of the 40's carries both the Ring and Pinion and the R&P Installation kit.

The Filling Station also lists the Ring & Pinion, but currently out of stock. Link

Classic Parts also has both Ring and Pinion and the Installation kit.

A member here on Stovebolt who goes by Mother.Trucker may also have them available. Once you have 5 posts here you could send him a Private Message.

Welcome to Stovebolt.com

You do have a nice looking truck.

hello , hi, thanks for the feedback. I had already seen "chevy 40 s" but I would like to have the choice. so there is no other supplier?
for information, shipping costs and customs clearance are 50% more ......
@+ Pascal

Did you try and contact Mother.Trucker? Send him a PM. He's not real active, but will eventually respond.
Besides Chevys of the 40's, Classic Parts carries them, but they wouldn't even ship anything to me in Alaska, they may not ship to France either.
The Filling Station has been my go-to lately for parts and have given me good service and reasonable shipping costs. You might contact them as well.

Hi ,
Thanks for the information.
Do you have contact details for " mother trucker " ?
"Chevys of 40's " accept to send me the parts in France . On the other hand shipping costs ....... aie aie aie .....
It may be possible to contact the manufacturer directly. Do you have any leads ?

Thanks

@+ pascal

Could you use a 3.38 gear set instead?

https://www.amazon.com/Yukon-Gear-GM55T-338-Performance-Differential/dp/B0078UCW60/

The “55T” one in that listing fits your differential.

Rock Auto sells the rest of the rebuild kit. I don’t know if they ship international.

It i use 3:38 instead of 3:55 , won't the axle be too longfor my 235 Cu engine and 3 speed manual gearbox ?
I've already ordered parts from " rock auto " delivery was very fast and shipping costs reasonable .
For the rebuilt kit , i have to choose in the list chevy truck 1946 ? ( my truck ) ?

@+ pascal

The difference between 3.38 and 3.55 might not be a big deal.

What transmission do you have and what size tire are you running?

Click HERE and then click the button that says "private message" near the center of the page that opens.

Hi ,
Currently , i have 4.11 in transmission and 215 /70 / 15 tires ( europan measures )

Although the driving speed on the road ( 50 mph , maximun speed allowed on the road in France ) is enough for me . I want to change my transmission especially to have a driving comfort and eventually lower my fuel consumption .
I've already done it on my Peugeot 203 pick up , where i fitted a Peugeot 203 sedan transmission ( 4.23 instead of 4.27 )

Thanks to Kévin for the link


@+ pascal

Need more info on your transmission to identify the ratios of each gear, particularly first gear.

Is the transmission the 3 speed that was original to the 1946 truck?

However, the info you’ve provided should be enough to calculate top gear. With a 3.38 rear end ratio in 3rd gear (1:1), and your tires which are 26.9 inches in diameter, you’d be cruising 50 mph at roughly 2100 rpm.

Yes , the gearbox is original on my 1946 truck ( chevrolet AK serie E 1946 )
I don't have the technical documentation for the gear ratios nearby .
I can provide them next week .

What are the rpm with 4.11 rear end ratio ( original assembly ) and 3.55 rear end ratio with same criteria ?

@+ pascal

This is the calculator I use to make this quick and easy.
https://spicerparts.com/calculators/transmission-ratio-rpm-calculator

There’s not much difference in RPM @ 50 mph between the 3.55 and 3.38. About 100 rpm in your case: ~2100 for the 3.38 and ~2200 for the 3.55.

However, either of those options drop the RPM significantly from your current 4.11 rear. It should take about 2550 rpm to get 50 mph there.

(By the way, I’m using 26.9 inches for your tire size).

Pascal, I first went with an early 50's POWERGLIDE passenger car torque tube diff, that would be 5 lug. You can marry the 3:55 torque tube with a '48 or earlier 6 lug AXLE. This works great although this stuff is getting hard to find in the States. If you join Vintage Chevrolet Club of America, you will able to place wanted ad and for this kind of swap.

That said, I later located a mid 60s truck rear end, 6 lug, lots of different ratios.

Best of luck
Jim

hello,

that's it I ordered and received ring and pinion. I took them from "chevs of 40s" the game offered at "amazon" did not correspond to my vehicle. on the other hand , the price .......315 dollars for 2 pieces, 224 dollars for shipping costs, 117 dollars for customs clearance taxes.
now I will open the differential to identify the good bearings to buy them in europe
for me it seems obvious that I have to remove the bridge rather than change ring and pinion in place?

@+ Pascal

Pascal,

Check out this 1941 Car & Truck Shop Manual resource document for your 1946 AK as it covers 1941-46 trucks and provides details on your ring and pinion change out.

Section 4 (starting on Page 86) covers your truck as the car and 1/2 ton truck rear axles use the same steps for service/repair, except for the minor difference listed on Page 93.

Looking forward to seeing and hearing more on your project.

Dan

hi Dan ,

thanks for the link ; it's really interesting and useful .
i'm wondering if i remove the bridge from the truck or replace the ring and pinion onthe truck ? (like the chevs of 40s )
i'm really going to have to learn technical english because on translation .......

@+ pascal

Pascal,

You will need to remove the entire torque tube and differential assembly from the truck to replace the ring and pinion gears.

Others will come along and add more details and helpful tips.

Dan