C6 Extension Housing

[70_F100]

The one in my 70 F100 LWB looks like the one in the illustration linked to the original post.

I'm not sure whether or not the dentsides had the same setup, as Fordman suggested. He may be right.

If you want to build the 460 tranny without disabling your truck, I'm guessing your best bet would be to check with a local transmission shop or salvage yard and see if you can find another tranny like yours.

[BobbyFord]

Trust me, I've been looking locally with no luck.

[mmerlinn]

Let me explain what I'm doing. I can use the housing that I currently have in my truck (the nasty, dirty one pictured) but I don't want to. I'm swapping my 360/C6 for a 460/C6. The 460 trans that I have is out of a passenger car and has the long, slip-type extension housing and I want to swap out it with a short shaft and identical housing like the one that is on my truck. I don't want to disassemble my 360 trans to build the one going in behind the 460. I want to rebuild the car trans without having my truck disabled.

In that case you need one exactly like you have. That particular housing is quite rare and hard to find. The shaft is very easy to find and any one of the 3 different 10-spline shafts will work for you. Not sure how hard the yoke is to find, but you don't really need another yoke if you are just going to swap engine & transmission.

You might be stuck with building the transmission with the correct output shaft, then using your tail housing when you swap the engine/transmission. Only thing to be careful about is that there will be nothing holding the shaft in the transmission so it could fall out whenever you move the transmission. These 10-spline shafts do not use a retaining snap ring inside of the transmission and have no snap ring groove in the front splines.

[BobbyFord]

Let me explain what I'm doing. I can use the housing that I currently have in my truck (the nasty, dirty one pictured) but I don't want to. I'm swapping my 360/C6 for a 460/C6. The 460 trans that I have is out of a passenger car and has the long, slip-type extension housing and I want to swap out it with a short shaft and identical housing like the one that is on my truck. I don't want to disassemble my 360 trans to build the one going in behind the 460. I want to rebuild the car trans without having my truck disabled.

In that case you need one exactly like you have. That particular housing is quite rare and hard to find. The shaft is very easy to find and any one of the 3 different 10-spline shafts will work for you. Not sure how hard the yoke is to find, but you don't really need another yoke if you are just going to swap engine & transmission.

You might be stuck with building the transmission with the correct output shaft, then using your tail housing when you swap the engine/transmission. Only thing to be careful about is that there will be nothing holding the shaft in the transmission so it could fall out whenever you move the transmission. These 10-spline shafts do not use a retaining snap ring inside of the transmission and have no snap ring groove in the front splines.

Yeah
I have already bought a nice used output shaft. The yoke is also easy to come by.
I think someone must have ordered this truck. I don't understand why they got the 3600 lb. axle, flexomatic springs and chose a 360 instead of a 390

[70_F100]

I can use the housing that I currently have in my truck (the nasty, dirty one pictured) but I don't want to. I'm swapping my 360/C6 for a 460/C6. The 460 trans that I have is out of a passenger car and has the long, slip-type extension housing and I want to swap out it with a short shaft and identical housing like the one that is on my truck. I don't want to disassemble my 360 trans to build the one going in behind the 460. I want to rebuild the car trans without having my truck disabled.

It would be easy to clean that housing once you pull the transmission.

You might be stuck with building the transmission with the correct output shaft, then using your tail housing when you swap the engine/transmission. Only thing to be careful about is that there will be nothing holding the shaft in the transmission so it could fall out whenever you move the transmission. These 10-spline shafts do not use a retaining snap ring inside of the transmission and have no snap ring groove in the front splines.

Swapping the housing would definitely be the best route, IMHO.

Don't worry about the shaft falling out. If you get the entire transmission built without it falling out, it's not going anywhere while you're waiting to install the housing.

If you're considering selling the current transmission once you have it removed, consider that the purchaser will most likely have a similar tranny in his truck, and can do the same swap on the tailshaft housing.

[sideoilerfe]

Or, here's a thought: Just use the new transmission and change the drive shaft to one with a slip yoke. Cost will probably be the same however less work.

[BobbyFord]

I figure as long as I'm rebuilding the trans, I want to swap out the output shaft and keep the bolt on driveshaft. I guess I'll just use the housing off of my current trans.

[70_F100]

BobbyFord, PM sent!!

[Rjshove]

just so happens that I have the same transmission. PGB AK6 tag, and an L Servo.
The Transmission casting # is D2T and I don't remember the rest.
I do know that the C6 didn't change much over the years internally, except some of the newer ones.
I also have a 68 F100 390 truck with a similar tail housing, BUT not like the picture u have on this page.
The 68 looks like the print out in the schematics and Diagrams/ Section G/ C6 Extension Housing and related, for the 68 72 on this site.
Not sure, but I am using the one u have pictured here, I will use a drive shaft out of the 4 speed truck and have it cut and re-balanced. IF the one I have laying loose doesn't fit, not sure what it's out of.
1973 must have been a change year.
Anyway, the rear part of the drive shaft SHOULD be the same from the carrier bearing back, so the front drive shaft should be the only part needed to make or fit.
I have taken the standard slip yoke transmission and put it in with a long single tube drive shaft.
I have this setup in my 68 long bed, C6, with a 429. NEVER had any problems, and it's been that way since 1992!
Good luck, ray
PS, If u want to stay with the flange, then the transmission U ARE putting in will have to be taken apart completely, remove the snap ring on the main shaft and slide it out, and then put back together.
The Flange style DOESN'T use the internal snap ring on the main shaft to hold it in, it is held in by a LARGE snap ring at the Roller Bearing in the shorter Tail housing and the 1 1/2" nut, sandwiching the flange, speedo drive gear to the bearing. The flange tail housing will come out (off) w/o tear-down. Just remove the tail housing bolts and it will slide out with everything attached, including the governor and sealing rings. I don't know the torque on the large nut, I set mine at 200 ft.lbs. with red loctite. The seal # is 410308 National for about $9.00, pay attention on how you take it out and don't let them try and sell u the one that doesn't look like the one mentioned, u will be glad u used the heavier seal.
Hope this helps Good luck Again, Ray

[Rjshove]

Find a C6 slip type drive shaft out of a 73- 79 ford truck or car. I haven't looked under my 76 390 C6 truck. Wait.... I will do it now!!
I just looked, my 76 F250 HAS the single tube with the slip yoke. DO U HAVE the drive shaft from the donor?
ANY drive shaft with correct rear u joint and length will work. If it's to long, have it cut, or they will build you one!
Also the gear selector may be different, if it is, remove the old transmissions pan, drop the valve body, remove the shaft and kick down, using a 7/8" boxed end wrench by slipping it over the kick down part. Once u have the nut off, pull out the selector and the kick down comes right out, Easy! Make sure the detent is positioned correctly, reverse the procedure.
Replace the seal and the o-ring if you haven't because u can't w/o doing this all over again.

[BobbyFord]

This is an 8 year old thread