47-55.1 Changing Rear End Gears 1950

[DaveDave50]

My 1950 3100 runs very well but starts groaning over 52-54 mph. Am considering changing the ring and pinion from a 4:11 to something better, however, have found 3:55 the only readily available. Not sure it will be worth the work and cost to improve speed only 13%. Anyone out there have experience with this or leads on lower ratio rear end gears?
Thanks in advance for your feedback.

[enick72]

other than changing gears (of course to keep all orig), the other options are change complete rear end or trans with a T5.

Patrics offers a 3:36 set up for around $600, that's everything to do the job.

[steve53]

patrics? i could be interested in that as well.

[enick72]

http://www.patricksantiquecars.com/chevrolet.htm

The website is not real good but just call and talk with him. He is very nice and has a cat. that he will send you.

[RBear571]

Dave,

I have the rear end gears from Patricks in my 1950, my Dad bought them quite a few years ago when he first re-did the truck. It really makes a difference and made the truck a lot more driveable and enjoyable.

[Wrenchbender Ret]

The 338 gears are for 55 up. 3.55 is about right if you still have the stock engine.

[raycow]

If you are dead set on keeping the torque tube, the Patricks gears are pretty much your only choice. However, for what the gears cost, plus set-up, if you have to pay someone to do it, you can convert to open drive for a lot less money. This gives you two advantages: a wide range of gear ratios, and the freedom to use almost any transmission you might care to run.

The easiest open drive conversion is to replace the center section with one from a 55-62 1/2 ton. This is almost a bolt-in, the "almost" part being that you have to weld or otherwise secure the pivots on the spring mounts. If you don't do this, the axle housing is free to flop around on the springs. The 55-62 rears don't give you a great improvement in gearing, because most of them are 3.90. However, this is an ideal setup if you want to run an overdrive transmission. One of these center sections and a T-5 would be just about perfect. Or, go with an overdrive 3 speed if you want to keep a column shift.

Ray

[WA1KPD]

IMHO. After a year with my 40 3/4 ton you start increasing the speed, you need to start thinking about increasing the brakes and changing the steering.

Stock systems just are not made for higher speeds.

Get used to cruising at lower speeds on the back roads the truck was made for. Its fun. In addition I took my GPS out with the truck one day and found that the speedometer was reading 5-7 miles slower than the actual speed. So when I thought I was poking along at 38 I was really doing 45.

[CTZR1]

I put Patricks 3.55 in my '49 GMC with the stock 228. Well, with the mods I made the 228, it is not stock any more. I was going to go with the saginaw tranny conversion too. I may be a while before I get her back on the road to see how the modifications suit me...she is a work in progress.
But other than swapping out the rearend, re-gearing it is not all that difficult.

[steve53]

yeah with the stock front suspension/steering on my truck, going 50 feels like going 90 in a late model car. not to mention you hit a pothole and the truck decides it wants to go in a slightly different direction

[Root2812]

I'm looking to retain the originality of my 216 engine, 4 speed tranny, and torque tube in my 1950 3100. I tossed around the idea of regearing. I'd like to be able to cruise in the high 50mph range with out tearing up that old 216. I think the 13% speed increase mentioned above would be enough to satisfy me since I'd go from about 50 mph to about 56-57.

How much does these parts cost if I do it myself? Also, Im new to my truck and I know the speedo isn't going to be accurate like my newer cars but I'd like it to be close. Is there a different speedo gear that can be bought?

How about that 3:36? Would that work for me?

[48gmc]

Originally Posted by raycow

If you are dead set on keeping the torque tube, the Patricks gears are pretty much your only choice. However, for what the gears cost, plus set-up, if you have to pay someone to do it, you can convert to open drive for a lot less money. This gives you two advantages: a wide range of gear ratios, and the freedom to use almost any transmission you might care to run.

The easiest open drive conversion is to replace the center section with one from a 55-62 1/2 ton. This is almost a bolt-in, the "almost" part being that you have to weld or otherwise secure the pivots on the spring mounts. If you don't do this, the axle housing is free to flop around on the springs. The 55-62 rears don't give you a great improvement in gearing, because most of them are 3.90. However, this is an ideal setup if you want to run an overdrive transmission. One of these center sections and a T-5 would be just about perfect. Or, go with an overdrive 3 speed if you want to keep a column shift.

Ray

i have a 48 gmc 1/2 ton with a 228 and 411 gears. i want to switch to 355 gears, i have the torque tube that i want to keep and have a 4 speed that works great, can i just change the gears, is it much of a job, about how much for gears

[mr48chev]

Dang you dug up a 9 year dead thread.

I think I just answered you on another thread.

Patricks has become unreliable in the past couple of years in that there are complaints across the net on long back orders and no response.

The 3.55 swap is a good swap an about all the stock engine wants to deal with without lugging in low gear

Here is a quick and easy ratio calculator to figure rpm at speed with https://spicerparts.com/calculators/...rpm-calculator

[JoeDude]

I too am looking for a 3:55 ring and pinion. So far there is nothing out there for a 54 Chevy with torque tube. Chevs O the 40's says it will only work with 53 or older carrier. Jim Carter is out of stock. Any other good sites to look?

'54 restoration slowly in progress.

[mr48chev]

I'm thinking that there is no difference between the early torque rears up to 53 and the 54.

Classic parts lists the 3.55 gears https://www.classicparts.com/1940-54...ctinfo/93-511/

Then you need the bearing set https://www.classicparts.com/1951-54...tinfo/93-512B/

With those two pieces you are looking at 884.90 with no labor charge yet plus any other additional costs. If you have a competent shop do the work you are going to have around 1200 tied up in that gear swap.

I'm rather thinking that all the vendors that sell the 3.55 gear set get their ring and pinion sets from the same manufacture. Patrick's are out of business as far as I know due to their poor business practices over the past few years.

Chevs of the 40's says the gears will fit the 54 housing if you run a 53 or earlier carrier. https://www.chevsofthe40s.com/detail...et_12_Ton.html They actually want a serious amount less than Classic parts does for the gear set. https://www.chevsofthe40s.com/detail...et_12_Ton.html
My guess is that you would have to change the carrier with other vendors offerings.

[greg_h]

54 came with 3.90 gears while earlier trucks came with 4.10. The same 3.55 gear set works in but styles but if you put the 3.55 gears in a 54, you have to use the earlier ring gear carrier. I assume it is a bolt pattern difference.

[MiraclePieCo]

Over on the HAMB they get really offended when you revive a dead thread. But I appreciate it when someone digs up an old thread. There's lots of good information in them, and no need for a whole new generation to trial-and-error relearn something that's already been figured out.

[JoeDude]

Assuming I have the 3.9 gears on my 54, everything I've gathered in this resurrected thread makes me think it ain't worth changing to 3.55 gears for just a 200 or so rpm gain and a bit of fuel economy.

Ring and pinion Plus a carrier from a 53 or older ....big bucks.
I did need the kit including the "okie" bushing due to leaky seals...500 bucks, out the door.
The shop may want $500 to do the job.

[mr48chev]

Originally Posted by MiraclePieCo

Over on the HAMB they get really offended when you revive a dead thread. But I appreciate it when someone digs up an old thread. There's lots of good information in them, and no need for a whole new generation to trial-and-error relearn something that's already been figured out.

I am probably one of the guys there who gives FNGs who find the long dead thread on Google to give folks a load of their wisdom a hard time.

48GMC's question post is totally relevant even with the 12 year lapse.

It still comes down to the fact that many of our "I want to keep it as original as I can" guys may have to bite the bullet $$$$ wise to be able to have their rig be able to cruise down the long roads at actual highway speed and not 20mph under it.

Yes there are rather simple ways to have the same and maybe better results. but then for them the truck isn't "original" anymore.

[GreasyLikeaBurger]

Might look at Deves Tech Page. He has a bsic walk through of the upgrade.
http://devestechnet.com/Home/DifferentialOverhaul