How much would it run to change the transmission in my '71 C10 from manual to automatic?

Question

When I bought the truck, it needed various things done to it. Now, though, it's drivable except the transmission's really difficult (you can slide into certain gears at certain times, but then not find them the next time . . . . generally frustrating). The previous owner had converted the shifter from the column to the floor, so I wonder (am pretty sure) if they screwed up.

In addition to cost, I'd like to know what parts I should be looking for and where best to look.

Also, would it be easier to just return the shifter to the tree?

Thanks

Answer 1

It really makes no difference in either place you put the shifter. I had the same thing done on my 71 C-10, and paid to have it done with a rebuilt turbo 350 auto on the floor for a driveout price of 1300.00. ( that included 12 month or 12,000 mile warranty)
If you choose to do the changeover yourself, you will need to look for a turbo 350 or turbo 400 tranny, and be ready to cut out the old tranny mount bracket and fabricate one in accordance with your new installation along with a few more headaches.
In short, it's probably not worth the few dollars savings to do it yourself. Just make sure you take it to a reputable Mechanic. Good Luck!

Answer 2

The '71 had either a TH350 Auto or TH400 on the big blocks, or the SM465 4spd manual tranny. The auto was shifted on the column, and the manual was on the floor.

The manual in those trucks don't shift worth a crap anyway, but are very strong. A TH350/400 would be an easy swap since it will bolt right into place. Your driveshaft will be too short when you stick in the automatic, a driveline shop will be able to add some length for not much cash.

If the motor is a small block, a TH350 will work, but it wont live very long behind a big block. the TH400 will cost more, but is a very strong tranny.

Is the truck 2 or 4 wheel drive? Your donor truck/tranny will need to be the same because the tail housings on the automatic are different between a 2 and 4wd.

Answer 3

Probably the clutch is going out in the manual transmission.

Well you will definitely go to the junkyard for any parts. All junkyards are different so I do not know if you can strip certain parts off the column you would need for the automatic shifter. Like is the plastic shift part that has the letters for D R 1 2 3 , is it still there. Then the shift handle, plus the column bar and the bars underneath that attach to the automatic tranny to shift it into gear. Just a matter of looking at the vehicle with the automatic and getting what you do not have on your truck.

But if you are going to change get a Haynes Repair Manual for your year and model to help you and for future reference.

And while you are under there, you should buy another rear end seal gasket. Take the old one off, take the OLD oil out of course, put the new gasket on, tighten up the nuts back on and refill with NEW oil. That is one most overlooked maintenance that I do on most cars I work on.

The mount brackets should be the same for the transmission. But on the transmission there are the short tail and long tail transmission like for the 350 transmission. So measure the manual transmission how long it is so you can get the right size. And even if it does not match up, then you can go to the drive shaft place and I say not more than $60 to lengthen or shorten it to fit and balance the shaft too. BUT if you do do it, it is very important that you ask him how to measure it correctly. You have to measure it in a certain way and he will tell you what to measure. And the LAST thing you do is change the tranny oil. Reason is, if the old one still has oil in it, you might start it and the transmission is bad, for one reason or another. Just make sure you have oil in it before you drive it though.
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Estimate varies. In San Antonio, I know I could do it for $150 in parts, tranny included. They have a pick and pull place where parts are CHEAP, but you pull them yourself. Otherwise add another $200 for the local rip off places.

Answer 4

i think i can help you this question because i am also converting a pickup from a manual transmission to a automatic.it can be easily done.you just will probably have to change the transmission cross-member.and probably change the the drive shaft.the auto trans will bolt right in.you might as well change over to a 4 speed automatic like the 700r4 that will give you a overdrive gear for better gas milage.the make cross members just for that switch.here are some sites to look check for parts. lmctruck , brotherstruck,pol(performance online) and cpp check these sites out and you will find what you need.also one more thing if you want to keep the shifter on the floor go to lokar.com and they have the parts you need for your shifter