The Stovebolt Site Forums The Shop Area Driveline 3.55 ratio axle

Hello,

Would a 3.55 ratio ring and pinion from a 1951 Chevy 2 door hardtop with Powerglide torque tube axle, fit in a 1954 Chevy 1/2 ton torque tube axle or carrier?

Thanks,

I know this has been discussed here but a Search failed to find anything. Not too uncommon as our Search feature is woefully out of step. Someone will come along with the answer.

Jim,

That is not an easy topic to search on. First, it would be 3.55, not 3:55. Also, the key words for passenger/car/automobile/Fleetline-etc/Powerglide would be quite complicated.

You could just search on 3.55 and see what you get. This topic (car 3.55 torque-tube rear R/P fitting truck torque-tube) has been discussed a few times in the last month or two).

As I recall, this will not work. But, wait to hear from someone who knows.

I don't know of anyone who has successfully put passenger gears in a pickup axle housing. The whole housing will work, but then you have 5 hole wheels in back and 6 hole in front. The 3.55 gear sets that are sold are actually for up to 53 models. However, I think with a few modifications, the 3.55 gears can put be put in the 54 carrier housing. Someone who sells these gear sets like Mother Trucker can tell you exactly what needs to be done.

The 3.55 gears from MotherTrucker will indeed fit inside a 1954 1/2 ton truck rear end, as long as you use a 48-53 truck ring-gear carrier.

What about the 3.55 R&P gears/carrier from a Powerglide-equipped 50-54 automobile rear end?

The gears from the pass. car power glide rear ends will not fit the AD trucks. It will fit in the 46 on back rear ends.

try patricksantiquecars.com, they sell the 3.55 gears right here online for the chevy torquetube rears

I didn't know there where 2 R&P gears/carrier.
1 for the PG and 1 for the manual trans.
It is the Powerglide R&P gears/carrier I'm asking about.
I added Powerglide to the original post/question.

Thanks tclederman

1951 Chevy car spec Rear axle ratios
PDF page 76 Auto Trans 3.55
PDF page 46 Manual trans 4.11

The main difference between the manual trans rear and the Powerglide rear in Passenger cars is the gear ratio, otherwise they're the same. They can be swaped with each other (did that on a freinds '50 2 door), but not with the Truck rearend.

Jim,

I think you are asking about the possibility of using a set of 3.55 gears out of a 1951 car Powerglide in a 1954 1/2 ton truck.

The answer, I think, is still: the gears out of a torque-tube Powerglide will not work, no matter what carrier you may try to use.

If that answer is wrong, maybe someone will give a clear answer on what parts from what source will work with a 3.55 R&P set from a Powerglide 1951 car installed in a standard 1954 1/2 ton truck rear end?

Patrick's sells different gear sets and bearing sets for cars and trucks so I would have to assume that there is a difference somewhere. That being said, I would expect that they may best be able to answer the differences question.

You are absolutely correct.
Just the 3.55 Ring & Pinion gear set installed on to the 1954 1/2 ton truck carrier.

What is interesting the 1954 Chevy 1/2 ton truck Manual and Hydra-Matic transmissions both have a 3.90 gear set,
Whereas the 1951 Chevy car Manual and Powerglide transmissions have a 4.11 gear set for the Manual trans and a 3.55 gear set for the Powerglide trans.

I thought I could pull the axle shafts and just swap out the entire torque tube and carrier but according to the 1929 - 1957 Chevy Master Catalog under shafts rear propeller O.L. Over all length for the 41-54 passenger car is 63". The 54 1/2 ton w/H.T. is 57 5/8" Both have 17 splines and are a Type C propeller shaft. Master Cat. does not specify if both ends have 17 splines just says 17 splines. The 41-54 passenger car Powerglide torque tube ,carrier and propeller shaft are to long to do a direct swap in a 1954 chevy 1/2 ton with a Hydra-Matic transmission, but the type and splines are the same in both the car and the truck.

According to the 1954 Chevrolet Truck spec 3100 1/2 ton PDF pages 99 and 100 both ends of the propeller shaft have 17 splines. So that means the car and truck pinion gear splines are the same.

So the only way it would work is if a set of 3.55 gears out of a 1951 car Powerglide fit into the 1954 1/2 ton truck's carrier.

It is not the pinion gear that would keep you from putting a car 3.55 in a truck torque tube.
It is true they have the same splines for the drive shaft and use the same pinion bearings.
The problem comes in with the ring gear, it will not bolt up to the truck ring gear differential case.
If you tried to use a car differential case the side bearings would be incorrect and the spider gears would be to small for the truck axles.

Called Patrick's they said,

1954 1/2 ton truck needs to use a 1940-1953 1/2 ton trucks spool/differential case part number 3652336 1929-1957 Master Catalog Master Cat. also includes 55-57 O/D
To use his 3.55 ring & pinion gear set in a 54 1/2 ton truck carrier housing.

The powerglide spool/differential case will not fit into the 54 carrier and the powerglide 3.55 ring gear will not fit onto the 1940-1953 1/2 ton trucks spool/differential case.
He might be machining just the ring gear and using a 3.55 pinion gear from the powerglide carrier. I think the powerglide 3.55 pinion gear will fit into the 54's 1/2 ton carrier.

If you have a 1940-1953 1/2 ton truck all you need is his 3.55 ring & pinion gear set. You already have the correct spool/differential case.

So much for trying to cut corners.

Picture of 1/2 ton Rear Axle click on picture to expand