I have a 700R4 in my 1970 that has given me nothing but trouble since I got it 2 years ago. I cant keep it in overdrive and I have tried the electric lockup and the vacuum lockup and nothing seems to make it work. I have had a transmission shop adjust the TV cable and it shifts fine, until it goes into overdrive, then it goes back and forth unless I keep the car over 70. Does a 200r4 act like this, and if I swap a 200r4 into the velle will it act like an overdrive transmission or a clunker like the piece of %(*# I have now?

Any input will be thouroughly appreciated.

What ratio rearend gears are you running?

before you blow the thing give Chris at CK Performance a call. Also consider TH400 Gear Vendor Combination as an alternative. If you go 2004R, you'll probably have to pay big bucks to get a bullet proof one.

I have 3.08's in the rear end. I never thought about the gear vendor option but isnt that big bucks? I am not really pupming out big horse power, the car is a daily driver which is why I wanted the overdrive. The engine is pushing out 300 HP at the most, would a 200r4 handle this? I would keep the 700r4 if it ran good but the kits you have to put in it suck.

Jay,
The 3.08 gear is probably why the trans keeps shifting in and out. My 85 Blazer had 3.23's and I would not even bother putting the 700r into od until about 65 -70 mph. The load on the engine combined with the low rpms is why it is shifting out of od. with that trans in a heavy car like a Chevelle, you would probably be better off with a 3.73 or so gear.

What year 700 is it? I believe the early ones locked up using a shift valve like the early 200-4r did. If that's the case the gears would be a big part of the problem as Bill said.

AHH, so if I put a larger gearset in the rear end would I be a whole lot better off? a new gear set sounds better than buying a new tranny.

Check out http://www.700r4.com/faq/faq.shtml or just search for Bowtie Overdrives. These are truly great transmission that if built correctly can handle alot of power and last for hundreds of thousands of miles, in a work truck or a street car. The main problem is many people, including tranny shops have not done their research and try to adjust them them like th350 or th400, And that just wont work. These trannies require proper carb linkage also if running a holley or edelbrock. I smoked 2 of them before I done my research and figured that out. I have one in a 86 k5 running 38 inch tires with 3.08 gears and after I finally built it right...I love it. 21 Mpg...perfect shifts..

You need the B&M Speed Control (see link) to control the lockup. With this unit, you can set the minimum vehicle speed at which you want the converter to lock up. Once locked, the unit doesn't allow the converter to unlock until about 5mph below lockup speed. This prevents the constant locking/unlocking you describe. Cost if I remember correctly was about $139 from Summit.

http://www.lildevilmotorsports.com/bm-racing-converter-lockup-control-with-mechanical-speedometer-cable-8ppm-pulse-rate-p-3394.html

My '93 S-10 Blazer has 3.08's with a 460LE (essentially a 700R4) and it loves to shift in and out of lockup and OD unless I am above highway speed with no incline to the road.

I built an '86 Olds Cutlass a few years back with a 350HO crate motor, TPI injection, and a 700R4 transmission. The stock rear had a 2.14 non-posi. Needless to say, the trans acted very strangely. After rebuilding the rear and putting in a 3.42 posi, the car/trans was right!

I would change your rear to 3.55 or 3.73 and you'll be happier.

These are all great inputs and I appreciate it. The funny thing is I got the tranny from Bowtie Overdrives in Hesperia Ca, I think I will give them a call and take it up there on a weekend. I will put in some 3.73's because I was thinking about that anyways. The B&M kit looks promissing so I might give that a try.