Thread: looking for the right transmission

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My father willed me his old 1972 chevy cheyenne, I've been driving it for a year. What a gas hog! Ten miles to the gallon. I've decided to restore it, a little at a time. I plan to start with the transmission since it seems to be slipping. My plans are to never sell this truck and I am not concerned with returning it to correct original condition. I was wondering about what transmission to put in. Is there a 4 or 5 speed overdrive tranny out there that would bolt up to this 350 engine or some type of modification I can do to this th-350 to make it an overdrive tranny? Heard something about a 700r4. Whatever I get, it needs to be high performance capable. What I want to do is get something used so I that I can rebuild it myself. also need to know about parts, special tools, instructional tapes or DVDs and step by step manuals or books for same. I thank all who answer in advance for all your help and advice.

700R4 is an overdrive transmission and they do make them to fit the sbc... However, even some of the transmission shops have a problem getting them to hang together when you put horsepower to them, might not be a good one to learn on. IMO you'd be better off buying one from a reputable rebuilder put together with the pieces to handle the horsepower of the engine you're building and complete with a warranty. Even just setting the TVR cable wrong will smoke the tranny in a big hurry....

Michael; I got a two wheel drive truck with a automatic over drive.
This thing just can't take the HP, figure out what you want.
Do you want good fuel milage or performance for the HP.
I'm ready to rip my out and go and get a turbo 400.
Mine has broken twice. Kurt

How about something like a built TH350 and a Gear Vendors overdrive unit? Not cheap, but I understand they work well and hold up under HP.

http://www.gearvendors.com/testimonials.html

Don

If you have never rebuilt a tranny, your best bet is to leave it to the professionals. By the time you gather all the books, DVDs, and special tools required you will be 1/2 way there. A transmission is a very delicate and precise piece of equipment and not a good choice for a novice to tackle, esspecialy an overdrive model. If you must do the work yourself go with the TH350 or the TH400.

Start off by rebuilding the one you have----and if that doesn't work out, then at least you have tried it without spending a lot of money

do you have a tranny jack????

I would go with the th400. The 700 do not hold up well with alot of horsepower. Haveing rebuilt 2 of them for a friend we finally went with the 400 and have not had any problems. He has a 89 chevy 4x4 and the 400 holds up alot better under stress.

I'm in the process of putting a 2004R in my 56 chevy - started the install yesterday. If built right they can take mega HP & stay together. they are a straight bolt in - replace a 350 without a new or shortened drive shaft. Will report the outcome in a day or two.
Doug

I just read a post ( on another forum maybe ) which rates HP consumed by various transmissions. The most efficient trans out there is the two speed powerglide.

But the powerglide is irritating as hell in city driving.

Hey.. will the gear vendors unit fit on a powerglide?

Welcome to the site, Michael:

I think I'm hearing you say that mileage and performance are your goals. The people at Raptor have been building 700R4 transmissions for a long time that routinely handle in excess of 500HP/500 FP of Torque. They're not cheap, but if you truly want to have a performance engine someday, the 700R4 can be made to handle it. Raptor's site is:
http://www.transmissioncenter.net/highperf700r4.htm

Bow Tie Overdrives also sells a complete line of transmissions and kits to take tour truck from a TH350 to a 700R4, 200R4, 4L60E or 4L80E. Their web site is:
http://www.bowtieoverdrives.com/

Take some time to look on the web and study your transmission options. The 700R4 is fairly straight forward to "bolt in" but will require some modifications in placement of cross member and several other things. You'll need some help actually removing and installing the transmission (unless your Hercules) as they're heavy. Us "old guys" use a jack made for transmissions!

After some study, decide how much you want to spend. If you go high and get a transmission that handles a lot more than your current 350 engine produces, that's ok. If you get an inexpensive transmission and grow your engine beyond what the transmission can handle, you'll buy it again!

Have fun and let us know what you come up with. Put a few pictures of your truck out here for us to look at.

Regards,
Glenn

All good points given here. What I would be considering though, is the cost differential between a good rebuilt THM400 and a high-performance overdrive. The 400 will handle just about any amount of streetable horsepower you want to feed into it, but will still be the same 1:1 third gear that you have now in the TH350, so you will not improve mileage with it. The overdrive trans must be built to handle additional hp and as seen in the link provided by Glenn, they are not exactly cheap. You have to sit down and figure the miles you will go with this truck, the cost of gasoline and the savings you would realize with an overdrive. I think you'll find that it might take a considerable number of years of driving to make up the difference in fuel savings between the THM400 and the 700R4. Now, there is a benefit in the 700R4 over the 400 in addition to the overdrive gear and that is the numerically higher first gear ratio that will provide a better launch.

It's sometimes a tough call when you start to modify your ride because of the give and take both ways. We want it fast with good mileage and that's tough to do on a budget.

Hi,
I sell 5 & 6 speed overdrive transmission that will bolt to you Chevy 350 engine. I have everything except the pedals & linkage in stock.

Many (most) trucks from that era had serious drinking problems. I would find a good tbi 350 donor truck and use the whole drivetrain and computerized engine management system. I know my 99 Suburban 350 could cruise at freeway speeds and get 19 mpg effortlessly.
I doubt if just changing the transmission will help much.

Well so far so good. Have only drove it about 3-4 miles to home from my buddy's shop were the work was done. The rain will not stop so I can get on the highway & see what I have. Will report more later.
Doug