VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Ring gear and pinion.....3:55 ratio

This place has a set to make a direct swap to my 38 coupe for $429. Has anyone ever done this or know about this vendor?

http://www.thegearshop.net/store/cart.php?m=product_list&c=60

This tech says it's like driving a completely different car after the swap. It should make driving 65-70 a easy task.

Never dealt with them but I look for clues when I go to a website. I found not very much information at all on the site about their products, in fact the webpage is pretty scewed up, to me that indicates how the rest of the business is run. I may be wrong but first impressions weigh heavy with me.

I would stick with someone like Patrick's who has been a great friend to the restoration community. You just give them a call and be prepaired to talk a while. Patrick can supply you with the same 3.55 gear for $399.95 and listed on his site he has all of the parts you will need to complete the restoration/upgrade of your rear end.
Denny Graham
Sandwich, IL

THANKS. That's exactly what I needed to know. Sometime this summer I should be about ready to drive this ole chevy a few miles. So far, all I've done is throw money at it and find another safty problem or two. Thanks again.

I'm still thinking that a 3:55 is too tall a gear for an 85-90 hp engine. Wouldn't a straight drive 54 gears with around 3:70 range be better for all around driving.

What were the straight drive ratios for for 53 and 54 and will they (torque tube and ring gear and pinion assembly) swap out in a 41 as easily as the 3:55 P.G?

A 3:55 is not unlivable, maybe a bit hard on the clutch but yes, it certainly is going to effect the acceleration and load carrying ability. Obviously that's why they didn't gear them like this in the original vehicles. If you want the vehicle to perform as it did back in 1938 then leave it alone and be satisfied with the stock gear and lower top speeds.

I’d love to find a 3:70 for my 1950, 3604 rather than the 4:10 that I have in there now but they don’t exist for the Eaton HO52 rear end. The stock 4:57 was fine for hauling and the acceleration was great, 45mph toped out for long distance. The 4:10 is good for about 55mph but acceleration is not that hot and I’d hate to try hauling a full load. A 3:70 would get me on the Expressway but it might take me a mile or so to get up to speed and I wouldn’t be able to haul my “big old wife” around with me anymore.

So all of the choices are a compromise, the factory balanced the power applied to the rear wheels with the speed as best they could back in the day. If your expectations are for your 1938 vehicle to perform like your 2010 Malibu then become a hot rodder, gut it and put in a late model drive line.
Denny Graham
Sandwich, IL

Your 1938 Master all ready has a 3.73 ratio so the 3.55 would result in only a 5% reduction in engine speed. That would mean you could cruise 3 MPH faster at 60 MPH.
I have a 3.73 in my 1939 ( it had a 4.22) and 65 to 70 MPH is a breeze. Not sure that I would want to drive one with leaf front springs at that speed for any length of time unless your iron man.

Why not use a 3.55 gear set out of a '50-'54 powerglide equipped car? That way you get OEM quality gears for a small fraction of the aftermarket gear price. Street rodders pull those rear ends and practically give them away. I got one for $100, and that was high but I wanted to get started on the project. The gears are going into my '36 pickup using a '37 car rear axle to accept the hypoid gears. If anyone is interested in pictures showing how easy this is, email me at rwaldbaum@aol.com.

I'd be leery of any oddball aftermarket gears. They are probably made in China.

I beg your pardon sir... I have 125 screaming H.P...ROFLMAO

57 chevy 235 cu. in.

BTW..I do have the orginal 216 if anyone wanted to be correct.

I understood that the 3.55 set was not exactly a drop in for the 1938. Also, one of my friends got the kit from Patricks and he didn't have the spider gears for his rearend.

That website that was first mentioned is a screwed up mess. I wouldn't be too quick to do business there.

Old 216, I took photos of the '37 and '51 (3.55) gears side by side if you'd like to see them. The moderator of the 1936 Chevy Owners forum asked me to document the project for a "how to" article.

The gears and all the other internals except the axle shaft lengths and driveshaft diameters are dimensionally identical. That is no problem becaues you reuse your old driveshaft and axle shafts. The only important difference is the pre 40 pinion has 10 splines and the 40 and up pinion has 17 splines.

That's an easy one to fix. The splined female sockets are removed from both driveshafts by simply chucking them in a lathe and machining out the weld bead that holds the splined female socket in the back of the driveshaft. That can also be done with a hacksaw and file, it's just more work. With the weld gone, the sockets fall out. Then the 17 spline socket is reduced in diameter and welded into the early driveshaft. Then you're mission accomplished.

In doing this project I also discovered that the vendors like Chevies of the 40's are selling the wrong driveshaft seal, and they know it but don't care. The seal they are selling is for a 1 1/16" shaft and the diameter of the early driveshaft front end is 1 1/32". A call to the Timken seal tech line turned up the solution to that problem.

36 1/2 Ton,
thanks for those details. I was making the point that the "kit" was not a bolt in solution.

Old 216 you are welcome. You are right that the kit is not a simple bolt on answer to altering the gear ratio. In that regard, no ring gear and pinion is a simple "Bolt in".

In all cases the relationship between the ring gear and pinion must be within specifications to work properly. The gear tooth contact pattern is checked by painting something on the teeth that will be rubbed through to show where the teeth are actually contacting each other. Then adjustments are made to adjust that contact pattern and the "backlash" (clearance) between the teeth of the ring gear and pinion gear.

That is nothing to be intimidated by though. The fore-aft position of the pinion is set by varying the thickness of the shim pack and the gear backlash is set by moving the ring gear right or left with the adjuster nuts. ASll of this is described and illustrated in shop manuals.

The concept is simple but for those of us grease monkeys who do it only rarely it takes some time. We motivated amateurs can do a better job than the professionals because we are willing to put in the time to do the job exactly right and they have to rush things.

Isn't doing stuff like this in one's own garage part of what makes the car hobby rewarding? I sure think it is.

Old 216, Your 1938 Master will have a 3.73 axle ratio, one of the advantages of the Master. The Master Deluxe had a 4.22 which gave it a very strong high gear. The 3.73 is already a good all around choice for power and crusing

ChevGene,
I was quite surprised and pleased to see that ratio in the specs.I wonder why they put a 4.11 in the Deluxe.

Fred

To quote 1937 engineering "Greater economy, longer engine life and higher cruising and top speeds are available in the Master than the M.D. becaue the 3.73 to 1 ratio rear axle is used. A sacrafice in acceleration and hill climbing ability , slight but noticeable, is the price expected for the economy, life and speed that is gained. The later qualities are, however, likely to be the ones demanded in conjunction with low first cost in an automobile.
With the 3.73 ratio the engine speed is 2766 RPM at 60 MPH while with the 4.22 ratio it is 3145 RPM at 60 MPH."

When I made the switch on my '39 gas milage went up from around 15 MPG at 60 MPH to 17 MPG at 65 MPH. It would climb most any hill in high gear before, now the power drops off below 35 MPH.

It was chepaer than makinging a smaller "economy" engine like Ford did with their 60 HP engine (which had a 4.44 ratio to move the car). Chevrolet could advertise 85 HP just like the full sized Ford V-8 engine.