The Stovebolt Site Forums The Shop Area Engine Shop Rear End Gears QUESTION (pics)

hey guys,
got a 235cui in a 57 Chevy 3200 series (stock 411gears). my RPM's are screaming at 55mph. I want to get this bad boy to hightway speeds with some new gears. I found the gears on Classic Parts Of America for $399. Is this my only choice for purchasing these gears? Seem like alot of $$$....looking for any other advice on a better price! THANKS! Check out the pics attached:
http://s537.photobucket.com/albums/ff340/johnnyrock70/?action=view&current=PA150098.jpg
http://s537.photobucket.com/albums/ff340/johnnyrock70/?action=view&current=PA150099.jpg
http://s537.photobucket.com/albums/ff340/johnnyrock70/?action=view&current=PA150100.jpg
http://s537.photobucket.com/albums/ff340/johnnyrock70/?action=view&current=P8080245.jpg
http://s537.photobucket.com/albums/ff340/johnnyrock70/?action=view&current=P8080244.jpg

yes, that's the about the price everyone wants ... you sure it's a 4.11? the standard ratio was 3.90, and with an OD trans it would have been 4.10 .... you might find an original OD trans cheaper than those gears, and the OD with 3.90 rear will move you right along

Bill

I just got through inspecting a 58 Chev Overdrive transmission I bought on eBay last week. It has a Muncie front section and a BW T10 back section. The overdrive is just like the ones I have always had behind Y-blocks. The .70 overdrive cuts your RPM way back on the highway but yet you can lock it out of overdrive and enjoy the 4.11 around town. It will behind a GMC 302. If you can find one complete with the lockout cable, relay and kickdown switch, it is a simple bolt together except for possibly shortening the drive shaft. A 12 volt relay from any car with a BW overdrive will work. A PTO cable will work for the lockout cable.

Shouldn't need to shoten the driveshaft, I didn't. It doesn't necessarily need to come out of a truck, either. A passenger car version will work just as well (mine came out of a station wagon). You can substitute the original relay for a 30 amp rated headlamp relay, I used one with a built in fuse from Standard-Hygrade. The kickdown isn't 100% necessary, and are very hard and expensive to get (you don't want to know what I paid for mine, and never have needed to use yet). While this isn't an issue with yours, those doing this with the '55s will need to swap the side cover to the pickup 3 speed side cover, as they are different.
BTW, if you can get me the codes off the 3rd member, I can decode them for you to get the gear option. The numbers will be a 2 letter and 2-3 number code stamped on the passenger side of the center section, in this location. Close up of what the code looks like.

Where would I look to find a 3 speed OD tranny and how would I easily identify it? For example what vehicles might have an OD tranny that would go into a late 50s / early 60s pickup? Or what codes would I look for on transmission?

Thanks,
Brian

Chevy offered an OD for cars and trucks from 55 through 69. The later OD transmissions (66-69) were full syncro. You should be able to find one at most swap meets, craigs list or ebay. If you have a 55-61 truck it is a bolt in, if you have a 62 or later with the short tailshaft it will require a driveshaft modification.
I use a GM cruise control switch for a kick down switch. They are available at Napa or most parts stores for about $10.
Fred

rfs56trk,

So can I continue to use my standard 3-on-the-tree shifter via use of a GM cruise control switch?

Thanks,
Brian

Another great source of products and information is Patrick's out of Casta Mesa AZ, just a little south of Phoenix. He specializs in pre-53'2 but know what carries over and has products for later models.

One thing he said to me some years ago about driving these trucks on today's roads: "...no matter what you do, you are still driving an egg crate through the wind and that takes a lot of power."

Also, by slowing engine down you may move yourself out of the engine's prime power band.

Hope this 3/4's of 1 cent input helps. It use to be 2 cents but with todays market conditions even the 2 cents has taken a hit!

Bob

If you have a 3 speed OD trans you can use the aforementioned switch along with the other electrical components. The electrical components required to operate an OD in the factory configuration are: Solenoid, govenor, relay, KD switch, and wire loom. A manual pull cable is also required. The KD switch is normally mounted on or near the carburetor linkage. The OD trans uses the same 3 speed shifter components.
Fred