The Stovebolt Site Forums The Shop Area Engine Shop What OD Transmission?

I currently have a VERY stock 57 3100 with 235 3spd with 336 open rear. I want automatic overdrive. What are your recommendations and where can I find details on how to setup your recommendation? Thanks.

(I know most of you'll suggest a small block up front but I want to keep the 235. It will have an Offy dual intake with Fenton headers and dual exhaust.)

I think you're going to have to shell out about $300 for an adapter plate like the one Langdon's has. Langdon\'s
Not sure of the overdrive on the 200R4 but, if it's the same as 700R4, it'd be plenty of tranny for a 235.
There's lots of threads on this subject. Try doing some varying searches and you're likely to come up with some good info.

I would recommend the 700R4 but definitely no on the 200R4. If a V6 can commonly blow up the 200R4, the 235's torque will give it a short life too.

I'd get the adapter plate and get any old 700R4 from some 80's F-body in a junk yard for a few hundred and I'm sure you'll be happy. You'll have to figure out something for the shifter though, like maybe some kind of a center console? That or convert it to a column shift. For a column shift, check out Ididit and see what they have in one of their nice steering columns. It'd probably be integral.

There is nothing wrong with putting a 200r4 behind a 235. Turbo charged Buick Grand Nationals had 200r4s in them and they tend to hold up pretty well. I know quite a few transmission guys that would rather build a 200r4 for their own hot rod projects instead of a 700r4.

However, if you plan on doing any towing, stick with the 700. My $.02

Phil

I'll have to agree some with Phill. I have driven cars all over the country with the 200R4 with no problems, all had over 100,000 miles. Then I had an 84 Caddy with 200R4 I had to rebuild and with the upgrades it went for another 100,000 miles, even with the dreaded 4100.( it had nearly 200,000 miles on the 4100 before i parked it. I have seen 700's that would not stay together. Most of the time depends on maintenance and the driver.

In the past, some have reported those adapters are a big pain in the butt requiring major reworking and then wind up breaking flex plates at times.You may want to check if these problems have been addressed before planning on using it.
An original 235 Powerglide will bolt right up,only two gears and no OD of course.Or you could change the rear gears to 2.73's and use a 50's Chevy or GMC truck 4spd Hydromatic with it's low first gear.

When I'm out shopping for one of these 700R4s; what am I looking for? What years and model cars are most likely? I get the impression from searches that I may want to look at late 80's A Body (Chevelle, Cutlas, Skylark)cars. Is that right?

I don't know if I want to do any major towing but it would be nice to know I could drag 3 tons 300 miles if I wanted to. Is that possible with a 235/700R4 combination?

I've read through a number of searches. They're plenty useful. I was looking for the ideas to be pulled together here and to hear any new ideas.

Thanks for your help.

If I did go with a 700R4, how would the torque converter lock be hooked up? Is it just a switch that I'd thow when at highway speeds? What if I forget to turn it off when I get off the highway, what damage am I going to do? You know I'll forget.

Jerry

3-tons 300 miles with a 235? I don't care what transmission you use, you won't be moving fast!

About a month ago I helped a friend move three cars about 1600 miles. We drove one, a '57 Chevy wagon with a 235 and a 3-speed. It did nearly 20 mpg and kept up just fine.

It kept up just fine with the 350 powered trucks that were each pulling a car behind them. If you're serious about towing over a distance you might want to rethink your motor choice...

I am terribly sorry. I got mixed up. I somehow confused the 200R4 for the TH200C. What I thought I was referring to was the "Turbo 200", which is a weak and fragile transmission. The 200R4 is a totally different animal.

Sorry. You're right. I realized my mistake while driving around today.

I thought I may be pushing it trying to pull that weight.

The most common source for TH700s is F-bodies (Camaros and Firebirds) and trucks. TH200-4Rs came in a whole buncha different platforms (G-bodies: Monte Carlo, Regal, Cutlass; B-bodies: Caprice, etc, Caddys and so on.) Btw, as I understand it, A bodies were discontinued (merged with G bodies) in 78.

You can do several things with the TCC locking. You can add a switch to lock it up. You won't forget too many time. It's just like forgetting to put the clutch in when you come to a stop. It'll remind you.

You can also get a kit to lock it based on vacuum, but the ones I've seen are sold by Painless and they're ridiculously priced.

My favorite solution is to make a wiring change inside the tranny so that it automatically locks up when it's in 4th gear. Here' a page on my site on how to do it:

4th gear lockup page

This is for a TH200-4R, but it's the same deal for a 700.

hth,

Truckedup brought up a good point -- one that me questioning my wisdom. I have a 56 sedan and am in the process of putting a 200R4 behind the 235 using Langdons adapter -- I have from another forum been informed that this is not a good idea due to vibrations and flexplate failures. I'm not about to bash Langdon on this as I haven't got mine up and running, but I'm would really like to talk to someone who has performed this swap and it has been sucessful. I'm still probably about 2 months away from having mine on the road. I'll keep all informed if interested.

Regarding TH-700 years, I think '92 and newer use electronic shifting so you may want to stay away from that. '82-'86 (I think) used a weaker forward sprag which was beefed up in later years. An earlier TH-700 can be retrofitted with the stronger sprag. If you don't plan on abusing the trans, then the weaker sprag should be just fine. I have an '82 TH-700 behind a warm 350 in my '57 chev hardtop and I haven't had any problems with the weaker sprag.

Regarding wiring the TCC, as earlier mentioned you may be able to utilize a valve body switch like the 4th clutch switch. There were many different wiring configurations for the TH-700, some may have the proper configuration and it is just a matter of getting power to the right pin. I activate the TCC in my '57 with a small toggle switch and power is routed through the 4th clutch switch. The 4th clutch switch is closed when in OD (4th gear). I wired the TH-700 TCC in my 55.1 with one exception...power goes through a brake switch. When the brake pedal is depressed, the switch opens and the TCC unlocks, regardless of what gear it is in.

If you are doing your own rebuild, make sure you check out the pressure switches that you will be using. I have come across a few that leaked.

Consider keeping it manual shift?

Look into a Borg-Warner T-5 5 speed. Fairly easy conversion from the 3 speed you have and great gear splits that will make your 235 run like a V-8!

I'm certainly considering the T-5. I did fail to mention that I'm lazy (I really don't want to shift in town if I can avoid it.)

You can also find 700R4's in S-10's,S-15's,Blazers, & Jimmys if they have a 4.3 V6.

IMO the 200R4 is alot stronger than a 700R4! I have been through a couple 700R4's drag racing my GMC Syclone that runs low 12's. I have a buddy that has a Buick Grand National that runs high 11's and all the stock 200R4 has is a 2800 stall.