The Stovebolt Site Forums The Shop Area Engine Shop New Tranny and Rearend Help

Well just as suspected my wife wants to put either and auto or truck 4 spd in our 52 3100. Does anyone know of a good shop in the Northern Dallas area that can do this for me? Or is it really too complicated to do my self. I can swap trannies and reaends I have never swapped a torque tube set up for a standard driveshaft set up though. By-the way, if any one is interested our 3spd tranny, torque tube and diff will be up for sale when complete.

Thanks for any help

What are your plans? What kind of rearend will you use? Can you weld?

I am a very very amateur welder, I would not trust my welds. I just want to put in, or have installed a rearend that will still have the six bolt pattern and will work with an automatic. My wife would like to have this truck as an almost daily driver, mostly city but maybe some highway occasionaly. It would be nice to have a rearend set up to pull our two horse trailer, about 3500 to 4000lbs when loaded, but that is not a requirement. I do not need anything for show, just reliable.

Sorry it took so long for me to reply, I was out of town.

Are you still planning to do all that with a 216?

I would say your goal is achievable, but you are going to need more power than a 216 could deliver. A 235 or even a 261 would help a bunch. You could use a 700r4 with 3.73- 4.11 rear gears. The 4.11 gears would probably be more desireable for towing. I wouldn't recommend any of this unless there has been substantial work done on the brakes... Disc up front would almost be mandatory.

Now for rear ends... a 54-59 chevy or gmc 1/2 ton truck should give you what you need, unless you want a posi. The ratio should be 3.90:1, however some gmcs came with 3.07:1. If you are looking for a newer rear with more gear selection, I would point you toward the IMCA modified F@#d 9 inch. You can get that rear end brand new with disc brakes in any lug configuration, and width for reasonable money. This rear end has almost an infinite number of gear ratios and posi tractions available for it. Many times it is cheaper to order this type of rear than it is to drive around to different wrecking yards with a tape measure to find a rear that will fit, only to have to completely rebuild it to make it work.

Is the 54-59 rearend a match? Or is there welding involved?

TIA

I have a 1958 235 in the truck now, it runs great so I hate to get rid of it. My horse trailer has brakes on it so I thought the current drum brakes would be sufficient for the short 5 mile country road trip to where I ride the horses.

I was hoping for something I could just bolt in myself. I don't need posi so the 54-59 will do if it will just bolt right up. If I can't locate one of those then I guess I will go with the Ford 9". I thought a 60-66 rear would bolt right up?

There is NO SIMPLE BOLT ON thing when changing from a torque tube rear. the torque tube is pivot mounted on the axle, and an open driveline has to NOT pivot. Usually, saddles are welded to the axle which prevents it from rotating on the springs. The pinion angle has to be set proberly to both transmit power to the rear and to avoid catastrophic failure.

There has been some discussion in the past about using the 54- 59 1/2 ton differential on a earlier 1/2 ton. This is done to keep the original brakes, and axle width. The axle still has to be modified to mount solidly on the springs.

I will be using the 9 inch rear on my 1940 3/4 ton. the 1940 3/4 ton has a 6 lug axle... 8 lugs were introduced in 1946 on 3/4 tons. I was able to spec the width (61 inches), the splines (31, which is stronger than 28 splines, but not as strong as 35 splines), the lug pattern (6 on 5.5 like original), the gears, the posi, and the size of the disc brakes. The axle with disc brakes and gears cost less than it would have cost me to have a used one rebuilt. If the 4.11 gears turn out to be too low, I can swap them out for a higher set in about 30 minutes in the driveway. Parts are readily available over the counter locally, or through internet order, so there will be no long down time looking for obsolete parts.

Anyway, good luck with your project, and look in to upgrading the brakes. It isn't the way you drive, it's the way the other people drive which makes it necesarry. I put the CPP disc kit on my 59 1/2 ton, and it was worth every penny. You can really feel the difference.

John

I am confused??? I was told a 55-59 1/2 ton rearend will bolt directly into my 52, but Bigbad above says it needs to be modified. Has anyone direclty bolted in a 55-59 1/2 ton rearend into an earlier AD model Chevy? Or know for absolute certain what needs to be done?

I can not give correct information on the rear as I replaced the rear, the drive shaft, the tranny and the motor. I also put disc brake all the way around. As far as stopping using trailer brakes, if they are in good condition they will stop the trailer and the truck. Excessive braking will surly heat them up but if your only going several miles you should not have a problem.
I am certain someone here will help you with you questions on the rear.

The 54-59 "pumpkin" or center section is a direct bolt on change. The challenge is that you would have to have new spring perches welded to your axle. If you used the entire 54-59 to 59 axle, you will likely have to grind off the existing spring perches and have them welded on for proper spring spacing and pinion angle.

To give you more background... a torque tube is great for delivering torque. The U-joints are held at the optimal angle for transmitting torque by the tube. The tube prevents the axle from rolling under acceleration.

On an open driveline, there is no torque tube to prevent the axle from rolling due to torque from the wheels during acceleration. The anti role is done by having a spring perch welded to the axle. The perch is flat on the spring side, and depending on the application can sit under the spring, or over the spring. The axle would be bolted to the spring with long u bolts, with the perches between the springs, axles and u bolts

Pinion angle also has to be set properly with an open driveline. There is little room for error as the efficiency of transmitting torque is proportional to the angle of the pinion. The angle also changes under driving conditions and load. One can not expect to take an axle from one vehicle to another and have those pinion angles match, as there are variables such as length of driveline, ride height, weight, etc.

To answer your above question simply... any rear swap in an AD truck from torque tube to open driveline will not be a direct bolt in. It will take proper setup, measuring and welding. once the axle has been setup to the application, and the perches have been welded to the axle, it will simply bolt in place. The above statement is also true if you just change out the pumpkin.

BigBad; I went out and looked at my 52 and I understand now, thanks for explaining it to me. I have a shop that has done this kind of work many times, a Rod Shop, I will be letting them install my new rearend.