The Stovebolt Site Forums The Shop Area Driveline Third member (pumpkin)

OK folks I'm going to try to put this as best as I can. I have removed the forward part of my 1949 enclosed drive (truck) rear end. The Torque Tube and the gears inside are completely gone. I also removed the rear end cover plate. Now I have in the truck an original housing with nothing in it. Had to pull the axles to remove the Torque Tube assembly. I read where a 1955-1962 (car or truck, I don't know which) third member or as some say a pumpkin would fit the original housing. This way you do not have to turn the springs around,weld tabs on or anything else. Just bolt the later model third member in, replace the original axles, put the cover on and add the oil and go. My question is #1-Is this possible? #2-Which rear-end do you use, a car or a truck. #3-What angle do you set on the pinion, providing this is possible? I know #3 is an estimate but close will be a starting place. I was asked to post this because it has not been addressed properly, so I'm told. If you have done this swap please post a reply on this so we Stovebolters can get it down for all the future Bolters. Thank you so much from me and future Bolters. If this is possible it would make an easy and fast way to go to open drive system. Thank you for all replys. Steven (Red 49 Truck)

Its been discussed but I have not did a search to see if I can find that thread.
Yes, you can make the change. I used a 55/56 pumpkin (truck) to replace the torque tube in my 52 panel. Like you said. Pull the axles, take the torque tube out an install the pumpkin, put the axles back in. The original is probably a 4:11 ratio. The pumpkin I got is a 3:90 ratio, not the best but better. I have heard that SOME 60's had a little higher gear but don't really know what they came in.

You will have to weld the "swivels" so that they do not flex up and down like the original.....or do some other way. I personally cut the old stuff off and slid perch blockd under the original rear end housing and made me a bottom U-bolt plate and used U-bolts. I set my pinion angle at 2deg. negative with the vehicle sitting on the floor with the weight on it. Once its set then weld the perch blocks to the housing. If you do a search I'm sure you'll find plenty to read about setting pinion angle but don't let it scare you. Its no big deal. Note, if you made your "U-bolt plate" its agood time to weld the shock bracket to the inside of the backing plate. The original shock mount was between the spring and inside the tire. I didn't like that and welded a stud to the u-bolt plate. Don't have to worry about it ever rubbing the tire. You may also have to weld a piece to the chassis to fasten the top end of the shock. IF you just weld up the swivels you wont' have to worry about this. Also be sure you get the rearend centered side do side which I'm sure you know to do.

Since you have an open drive shaft do know you'll have to change the tranny so you can hook up the driveshaft?...or are you using a V8?

...also, if your changing wheel size from a 16" to say a modern 15" rim you may want to move the rear end forward or backward to get it sitting in the fender well like you want it. Much has been said about flipping the springs around to move the rear end back about an inch or inch and half since the center spring eye bolt is not exactly in the center.....or makes sure you use the perch blocks from the dodge dealer which has three holes in the bottom of it....a center hole and one more on each side about 1 1/2" toward front or back!
While the pumpkin change is quite simply there are some little things to think about but don't let them overwhelm you. You do what works for YOU. Good luck.

Hope this helps and I'm sure others will chip in along the way. Just remember, measure twice-cut once!!

The 3rd member you would need would the '55-'62 Truck, the Passenger 3rd member is much smaller and has a different shape. The standard (and most common) gear ratio is 3.90, with options for a 4.10 (usually with overdrive) and 3.38 (Hydramatic).

Thanks for the replys. Anyone else just put your opinion in and we should get something good going on here. Achipmuck, I rebuilt a 4-speed SM-420 a while back and it was ready to go far as the open drive is concerned. When, I say when, I find a third member I will probably just see how the Lever shocks work. If they don't please me I've got a 1951 and a 1954 parts truck. I think I will be able to use one or both of those to rob the shock plates from I hope. I think I'll measure, plumb bob, level and what ever else about three or 4 times before I weld anything in place. Longbox55, I hope I can do a little better than 3.90 but time will tell. 3.50's would be nice. I'm going to have to get another digital camera so I can post some pictures. You know what they say, "A picture is worth a thousand words." Thanks to you both. Steven

Oh,I just changed out a 1956 Hyd. lifter 235 for a 1955 solid lifter engine so for now I'll stay with this "Blue Flame 235"
As far as the camera goes, when I get the money I'll get another one. Disablity pay ain't much. I know a bunch of you know what I mean!

Are the 3.38 rear gears from the 55-62 trucks with the hydromatics hard to find?

hydramatic trucks are hard to find, but the 3.38 gearsets to fit in the 55-62 rear are available from Patricks

Bill

Probably best use of time and money to with Patrick's. But It is good to check out all possibilities.

The 1955-1962 truck 3:38 gear set can be bought from any reputable gear vendor.
Randys Ring & Pinion


Tim

Nice link Tim. Thanks. I may want to put a 3:38 in the old panel one day since I have a 56 pumpkin in it. Just never know!

Right now I have the 53 pumpkin with torque tube. Your site is no good for me. Thanks though

You asked this question, "Are the 3.38 rear gears from the 55-62 trucks with the hydromatics hard to find?".
The link is good for the question you asked.


Tim

I have a '50 3600. If I ordered a ring and pinion set from Randy's, is it a 30 or 35 spline?

The link I provided is for a ring and pinion to fit a 1955-1962 1/2 ton pumpkin.It will not interchange with your original 3rd member.If you have the 55-62 pumpkin you can do the conversion.

Patricks has a 3:55 ring and pinion that might work for you.You need to call them at 520-836-1117 .


Tim

That one will not work, nor will the 3.55 gearset, as they re both for 1/2 ton.

Hello Longbox. I was wondering if you might know where I can locate some pictures of rearend carriers so I might can date my carrier. It is a 3:90 ratio and I'm going to put it in my truck using the 49' housing. Thanks a bunch. I've ask a couple of other people so maybe if you don't know someone else might chime in. Thanks , Steven Red 49 Truck

Hi all - does anyone have some info on how to definitely ID a 3:90 rear end?
I have this torque tube from a 1954 that I think should be a 3:90 that I want to swap, but need to confirm. Does this number "309" and the clock-like marking mean anything?

[image]http://i1310.photobucket.com/albums...0f9c816858c_zps9b1e5e6b.jpg?t=1388517486[/image]

Right now and for about 15 years I've been running a 1965 Chev pickup 3:08 ratio(6 lug) rear end under my 46, was a gift from a very good friend. The BIG plus for going this route is that there are many other ratios to choose from for these and not all that hard to find.
Best of luck
Jim

wurlitzer46,

Here is 1954 truck rear axle ID information.

Thanks - but is there a way to tell a 4:11 from a 3:90 half-ton rear end?
Does this casting number "309" and the clock-like marking mean anything?

[image]http://i1310.photobucket.com/albums...0f9c816858c_zps9b1e5e6b.jpg?t=1388517486[/image]

if not, are there markings on the gears?

Sorry, I posted the wrong link. Check the link above, again. There should be a code on the rear end that you can use.

Thanks, according to the diagram, it looks like the 309 is a month and date. I checked for a number on the other side, and found this:

3698954
D2

This doesnt match the "MU" code for a 54 3100 on the chart- anybody have an idea what D2 means?

Take the back cover off of the rearend housing and look at the back of the pinion gear.A number will be stamped on the gear, that will tell you what ratio it is.

Tommy,

What would be the code on torque-tube 3.90 pinion gear and the code on torque-tube 4.11 pinion gear?

Ok, I opened it up and the back of the pinion says 39 - 10. Also, counted 39 teeth on the ring gear and 10 on the pinion.

simple math 3.90 gear.

Tim,
I don't know about any codes on the torque tube rears. Just all the years I've been fooling with cars/trucks, was always told you could divide one number into the oether and come up with the ratio. Kind of like jacking up one side of the car and turning the wheel to see how many times the driveshaft turns.

Yes, I know that, Tommy
I am pretty good at math.

I was wondering about the number stamped on the 4.11 and 3.90 pinion gears: "Take the back cover off of the rearend housing and look at the back of the pinion gear.A number will be stamped on the gear, that will tell you what ratio it is."

Tim,

I guess the code you are looking for would be the numbers Wurlitzer46 found 39-10 for the 3.90 and 40-11 ? for the 4.11.

I Haven't taken a rearend apart in years, I always remember the numbers being stamped on the rear face of the pinion gear as being the ratio.

If Chevy had a different number stamped for a stock code I'm not familiar with that. All of the aftermarket gear companies had them stamped on the rear face of the pinion gear.

I wasn't trying to be a smart--- with the "simple math"thing.
maybe it came across wrong, sorry if it offended you, didn't mean it that way.

I think I have both a 4.11 and a 3.90 pinion gear, but I will not be back in my cold and snowy home until 3 January. I'll try to remember to look at the pinions when I get home.

Does anyone know what, if anything, is on the 3.55 conversion pinion gear?

Happy New Year

Hi All
For the record the pinion gear from the 1954 1/2 ton says this:
54 3697703 10 39 GM

10 teeth on the pinion, 39 teeth on the ring, 3:90

I have a set of 3:55 gears for sale
New never used with carrier
Give me a call 313-995-2768

Please post items of sale in the swap meet.