Inliners International Forums General Discussion Drive Train Degree of Difficulty: Ring and Pinion Swap?

Greetings Inliners . . .

I have read a couple articles, as well as, several postings here about the benefits of moving away from the 4.11:1 ratio gears that came stock on 40's era chevys.

The swap of choice appears to be 3.55:1.

How hard is this swap? What else in a stock '49 rear-end needs to (or SHOULD) be replaced during such major surgery?

Any advice will be greatly appreciated.

regards,
stock49

The least expensive way to do this is to find a the rear axle form a 54 powerglide car. They had 3:55 gears. I don't know if you can use the whole rear or not or if the ring and pinion will fit right in your housing. I did this swap in my 37 sedan and had to use the torque tube and axle housing from the 37 and had to have the splined coupling changed where the pinion meets the inner drive shaft. You just have to play a little mix and match to get all the right parts. I think the whole job cost me about $150

Gael

50-54 powerglide cars had the 3:55 gears. All you have to have is the tube/center section, but you can swap the entire rearend if you prefer. Otherwise a new set of gears can be had from Patrick's. As for other parts, it would depend on the condition of the parts. Bearings may need to be replaced. You might want to consider upgrading to the Bendix type brakes 52?-54.

Get a shop manual and study it.

Swapping in the 3:55s is a piece of cake in your 49 and the modern brakes are a bonus. Have this set up in my 47, I'm sure it's even easier in your 49. Believe the standard trans cars in 53/54 had a ratio of 3:70s which isn't bad either, most guys overlook this option. Difficulty now is finding either of these that are not rusted to bad. Last two I checked out were pretty bad.

Bendix brakes started in '51

The 1953-54 3.55 or 3.7 passenger gears only work in cars. For PUs you are limited to 1954 3.7 or Patricks 3.55

[This message has been edited by Pre '68 Dave (edited 04-30-2003).]

I was assuming the question was for a car.
But if it is for a truck, you can still use the car rearend assembly as a whole, and if you want to use 6 lugs, use axles and drums from a 41-48 car.

Sorry for the delay in replying . . . I was in Salt Lake City on business and didn't get a chance to check out the B-Board during my stay.

My rear-end and original breaking components are in excellent shape -- besides -- my intention is to keep everying as '49 as possible -- with the excepion of a few period correct speed parts. Lower RPM free way cruising would be a bonus -- but I will stick with a working 4.11 if the swap to 3.55 is difficult or risks screwing something up.

With that said, let me re-phrase my question. Can I purchase a 3.55 ring and pinion from Patricks or elsewhere and just bolt it into my existing Diff? Should any thing else be replaced during the operation (bearings etc.)? How hard is this?

We're talking about a car . . . a 2-door Fleetline Fastback to be precise.

Chapter 4 of my '49 Shop Manual shows the need for some specialized tools to shim and adjust the ring and pinion and to check backlash. Can these steps be undertaken without these tools?

Any insights will be greatly appreciated.

regards,

stock49

I find it easier and less expensive to swap out the rear axles and replace the trannys in torque tube Chevys. If you must absolutlely need the bone stock appearance, the gears are ok but are very expensive when all is said and done.In my 51 truck I used a 70-80's Chevy 4x4 6 lug axle. Only an inch or so wider and available in many ratios.Any 55 and up Chevy car stick trans will bolt in a 48 and up truck.Have a driveshaft made, position the axle and new axle spring mounts and it's good to go, well not that easy,lol.If your's is a car, a 55-57 axle will work as well as the various Nova and Camaro units.If you have a car and the early cars have the floor pedals attached to the bellhousing,you will have to somehow adapt a later housing to accept the 55 and up stick trannys.On my 37 Chevy truck I managed to fix the floor pedals on a later clutch housing with little difficulty.
In my opinion ,3.55's are an improvement over the 4.11's but not enough to run down the hiway at 65 in comfort.A good 235 will easily pull a 3.08 gear with little loss in getaway performance.

[This message has been edited by Tony P (edited 05-07-2003).]

What gears came on the 1950-52 Glide cars?

Will the splines match a 1940 car?

------------------
jku72
1940 Chev

All Chev PASSENGER cars that had the powerglide trans from the factory had 3:55 gears. This torque tube to differential, as a unit will be a direct replacement for all torque tube passenger cars back to at least 1941 and probably further back than that. I'm 90 percent sure that the gears would interchange back to late 30s, while the torque tube length may be different.

And yes the splines are same, otherwise this swap would not work.

I found the hard way that the axle shafts between 49-53 were not exactly the same. The length is the same but there is a raised cicle at the end of the axle to index into the brake drum, 49s are larger and affect the brake drum fit.

Again, this is an easy swap, just read up in your shop manual and it will go just fine. Keep the stock 49 axle/brakes if you want to keep it simple, the gear change is the best upgrade you can have in your 49, all else being stock.

stock49,
If what the manual show for tools is anything like the later ones, you don't need all of those to get the job done. A press, caliper and dial indicator whould probably be enough. In the end it's only the mesh between the gears that's important. Pressing on the new bearing to the same spec as the old one (pinion) should be pretty close, and adjusting the ring in/out till it doesn't bind in either direction would give you about a 90% chance of getting it right. Use paint on the ring gear to check wear pattern, and if looks right, then it is right. Otherwise shim pinion bearing so it does mesh right. Everything is in the manual.

jku72,
From looking at the Hollander interchange manual, you will have to replace the gears in your stock rearend as the driveshaft length changed in '41. Gears should be interchangeable from 37-54. Patrick's advertises that their gears are for 37-54 cars.

I did this swap on a 37 and had to use my original axle housing, torque tube, and inner drive shaft. The only hanp us on a 37 is that the spline on the front of the pinion on the 54 is not the same as the spline on the 37. I had to cut the splined bushing out of the out of the inner drive shaft from the 54 and have a drive shaft shop weld it into the 37 inner shaft. Not too bad a job but it has to be welded in straight and square. As someone else said it is the best thing you can do for cruising if you want to keep everything looking original.
I don't know which spline the 41 has.

Gael