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833 tailshaft swap

Garand-chan

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First post here, but I have an inquiry. I’d like to put an 833 in my ‘72 Charger at some point down the line, so I bought one trans that shifts into all gears and spins freely but it has the A body tailshaft. In that same deal, I got another one with the B body tailshaft for really cheap because it either won’t shift or won’t spin freely, thinking I could swap the tailshafts. I’m new and have never messed with transmissions, so am looking for confirmation that this is possible. Also, they both have the ball and trunnion setup. My driveshaft should be slip yolk. How do I overcome that? I’ve heard about conversions, but don’t fully understand. Hope you all believe in the philosophy of “no stupid questions.”
 
You’d need to change the output shaft, that’s a tear down of both transmissions. But yes, doing this will give you the trans you need for your car.
 
You should purchase a book from Passon Performance which will be a great help to you in regards to your transmission and what fits what. Also you will need a tailshaft and housing from a slip joint transmission. You will also need to match your Bellhousing opening to your input shaft bearing size. Your journey on sourcing parts is just beginning.
 
What? He only needs to change the tail shaft, swap the longer output shaft. May need to change the rear bearing, 307 to 308, but that’s a maybe.
 
What? He only needs to change the tail shaft, swap the longer output shaft. May need to change the rear bearing, 307 to 308, but that’s a maybe.
That would be cool if it were that simple. The bearings and stuff definitely need changing anyway, based on the pictures. I’ll know more once I get my hands on it and dig in.

DDCF9936-66DF-4B34-9E7F-E564C4865D6E.jpeg
 
Tear both transmissions apart. Keep separate. Take the short tail shaft, pit to the side. Take the long tail shaft, put it next to the A body trans. Take the output shaft of the B body shaft, put it next to the A body trans. Take the A body output shaft and set it aside. Now you have what is needed to make a B body trans. Look at the big bearing on the B body shaft, is it the same size as the A body bearing? If so, great, order a new bearing. Install it. Slap the now complete A body trans case to the B body tail shaft (you should’ve installed the B body output shaft into the A body case. Slip the B body tail shaft over the output shaft get the snap ring seated. Put the cover on. Now you have a B body trans. All you’ll need is new linkage, new thingy’s that bolt to the shifter studs, possibly a shifter. This is not hard to do. Get the book by Passon, you’ll be set. Set aside about 4-5 hours if you’ve never done it before.
 
Tear both transmissions apart. Keep separate. Take the short tail shaft, pit to the side. Take the long tail shaft, put it next to the A body trans. Take the output shaft of the B body shaft, put it next to the A body trans. Take the A body output shaft and set it aside. Now you have what is needed to make a B body trans. Look at the big bearing on the B body shaft, is it the same size as the A body bearing? If so, great, order a new bearing. Install it. Slap the now complete A body trans case to the B body tail shaft (you should’ve installed the B body output shaft into the A body case. Slip the B body tail shaft over the output shaft get the snap ring seated. Put the cover on. Now you have a B body trans. All you’ll need is new linkage, new thingy’s that bolt to the shifter studs, possibly a shifter. This is not hard to do. Get the book by Passon, you’ll be set. Set aside about 4-5 hours if you’ve never done it before.
Thank you so much. This is the most helpful thing I’ve heard on this subject hands down. I will pick up that book too. I’ve found physical literature to be really helpful in the past.
 
Got questions when you start, just holler.
 
I think you missed the ball and trunion detail.
 
Oh ****, I just reread his post. It still applies.
 
The old A body ball and trunion units have a different gear set. Can't recall the ratio but 1st is lower. About 2.9:1 I think? Not a big deal and can be beneficial. Also the reverse idler and the 1-2 slider may be unique so do not mix up the parts from either trannys and that includes the cases. The main shaft and tail housing can be swapped to a slip yoke style.
 
If you just swap the tail shaft and main shaft, you haven’t done anything but swap the 2 pieces. I never said swap gears, just the shaft and tail housing.
 
The old A body ball and trunion units have a different gear set. Can't recall the ratio but 1st is lower. About 2.9:1 I think? Not a big deal and can be beneficial. Also the reverse idler and the 1-2 slider may be unique so do not mix up the parts from either trannys and that includes the cases. The main shaft and tail housing can be swapped to a slip yoke style.
At this point, since I’m already 600 bucks into the ball and trunnion transmissions, would it make more sense to either modify or change my driveshaft as opposed to converting it on the tranny side?
 
If you just swap the tail shaft and main shaft, you haven’t done anything but swap the 2 pieces. I never said swap gears, just the shaft and tail housing.
Good advice but it still involves disassembling 80% of the transmission. I’m not saying that it can’t be done but there is some amount of mechanical aptitude involved.
 
Thank you so much. This is the most helpful thing I’ve heard on this subject hands down. I will pick up that book too. I’ve found physical literature to be really helpful in the past.
The best advise that you should take away from this is to get a copy of Jamie Passon’s book and read it at least twice before doing anything. There are also videos on the web that are helpful.
 
Sell them both and start with something that fits. I think you should be able to find one for under $500. main shaft alone is going to set you back at least $150
 
Sell them both and start with something that fits. I think you should be able to find one for under $500. main shaft alone is going to set you back at least $150
I’ll keep an eye out for another one, but all the ones I’ve seen that are pretty good are around a grand. Remember me if you see one for sale. Unless I find a better deal on a tranny, I’ll move forward assuming I’ll convert my driveshaft.
 
Not only that but my bet is the ball and trunion tail shaft housings are different than a slip yoke tail shaft housing. The arent the same for automatics. Might be cheaper to get a new style drive shaft with a slip yoke built into it?
Doug
 
At this point, since I’m already 600 bucks into the ball and trunnion transmissions, would it make more sense to either modify or change my driveshaft as opposed to converting it on the tranny side?
Depends what your purpose is. Ball and trunion parts may be hard to find and they are also not the strongest set up. If you go that route you can convert to the slip yoke setup like a 4x4 front driveshaft.

If you have to have a new driveshaft made anyway going to the slip yoke then might as well make a new driveshaft that uses the drive flange on the ball and trunion. Spicer makes the adapter I believe. Any driveline shop should be able to make this happen.

And here it is
https://www.amazon.com/Spicer-2-2-349-Flange-Yoke/dp/B00GAPJQC2

Then get the U joint and the slip yoke setup. Your drive shaft will look like this
1508738761_1310series2.5inchwithSplineandSlipDriveshaftforCHEVYG.jpg
 
Not only that but my bet is the ball and trunion tail shaft housings are different than a slip yoke tail shaft housing. The arent the same for automatics. Might be cheaper to get a new style drive shaft with a slip yoke built into it?
Doug
I’m open to whatever can make my car motorvate and probably not break itself. However, I’m a noob so I don’t understand what you mean. The only ways I figured I could make it work are either cut my driveshaft and weld in a ball and trunnion end on it or use a bolt on adapter like I’ve read in some other threads. But I don’t even know if they’re still being made.

98E12AB8-F468-4740-B099-9A1053C47C04.jpeg
 
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