The Stovebolt Site Forums The Shop Area Driveline ring and pinion change

I have talked with a friend and he said that I should just change the ring and pinion in my 1948 chev panel. I think that it has the 4.11 is that right? and was told to go to a 3.55. Will this do the job so I can run 65 mph without pushing the rpms. If not 3.55 what. Thanks again

Patrick's supplies and sells the 3.55 Ring & Pinion conversion for Advance-Design trucks. He also supplies and sells the installation parts package.

There is no other "easy" way to get a lower-ratio (lower-rpm) higher-speed rear end. Other options include replacing the transmission, drive-shaft, and rear end.

This will result in an approximated 14% RPM reduction at a given speed.

Are we talking about a 1/2 ton or 1 ton panel?

A good gear calculator
http://www.onlineconversion.com/bigger_tires.htm

Always a good question to ask. Ooops,

first48,
I'm starting the 3.55 conversion on my '52 1/2 ton pickup today. I bought the Patrick's gear set and installation kit. The kit contains all the "wear" parts that would normally be changed in a rebuild, including bearings. If you've never rebuilt it before, it probably needs a good look after 64 years. I have two rear ends. The first had bad differential side gears, differential cage, lightly scored axle halves, and the hooks to attach the spring saddles were badly rusted. The second rear had badly scored axle halves. I'm installing 99187 Speedi-sleeves (from NAPA) on the half shafts to repair them. I'll end up with a good unit by combining them. I'm glad that I took the time to do this stuff.
Dave Evans
52_3100

I strongly agree with Dave's emphatic suggestion to buy/use the installation kit. You most likely could obtain those parts yourself and save some money, if you can easily find part numbers and do not have to pay shipping from a variety of vendors.

My Suburban was very quiet inside after my restoration; however, after doing the 3.55 conversion and using all the replacement kit bearings and bushing, it is noticeably quieter inside my Suburban, even at higher RPMs.

I rebuilt my differential in my '51 1/2T burb about 20,000 miles ago.New bearings fasteners seals, axle bearings whatever. Now I'm thinking of putting in the Patrick kit. Any reason to get the installation kit if everything else is up to snuff? In other words, is there something special about the new ring and pinion that would require the installation kit?

Kurt

You will be good with what you have.
I might put in a new rear bearing as the pinion is the race for it and a bad bearing could damage it.

Thanks Dave.

Kurt

I agree with Dave. I do not know what comes in the R&P set, if it is just Ring & Pinion, you might need shims for the pinion bearing (I think that is where the adjustment shims are used).

All that comes in the R&P set is the gears. You may need an additional shim or two if you don't buy the install kit. In the installation kit is also a tool that spaces the pinion and bearing during installation (GM tool J-6040). The tool is .116 thick.
I also bought a thin manual from Jim Carter, Rear axle overhaul. Really good pics.
Dave Evans
52_3100

I have a 1 ton.

OK, I think the prior discussion doen't apply to your panel. If original, you will have a different rearend, a full floating Eaton with a ratio of 5.14. There are no kits to change the ratio but a used one from a later 3/4 Ton could give you a 4.10 ratio.