On my '70 GS I first swapped out the TH350 with a rebuilt 700r4. I like having OD at cruising speeds. It was built to stock specs, but is a later '92 model which has the 30 spline input shaft. The new 12" converter I bought was also a stock stall level. I thought this setup would be fine since I had a 455 with the TA212 cam, which they say can take a stock converter. Well, it will work with a stock converter, but in my case it struggled to idle when in gear, and was constantly pushing the car, fighting the brakes, at red lights. I have a manual switch for OD so that the lockup can only happend in 4th gear, which is fine with me. With the 3.42 rear end and 28" tires, full power took a couple of seconds to arrive from a standstill start if it was nailed hard. This surprised (disappointed) me since the 700r4 has such a low first gear. It would spin the tires on hard take-off but it worked real hard to do it. 1-2 shifts were OK at up to 1/2 throttle, but soft at higher RPMs. 3-4 shifts were always too soft for my taste. So here is what I did: - bought a 9.5" converter with lockup and 2600 stall. - installed a Transgo 700 JR kit, drilled the specified holes in the tranny plate. - installed the stronger springs and spring seat plate in the 1-2 accumulator. Started to block off the 1-2 totally, but figured it would be firm enough with the mods I was making. My research told me that this might lead to bang shifts at even part throttle so I modified the accumulator but left it active. - blocked off the 3-4 accumulator by driving a 1/4" ball into the feed port hole. Left out piston and springs. - Installed stronger spring in the PR valve which is located in the pump housing, also installed larger .500 Corvette PR valve for more overall line pressure. It had one that was .420 or so. - Installed Corvette servo along with extra spring and also I ground 4 vents in the edge of the plate as specified in the kit. - Left out all but 2 check balls. - Took out check ball in the end of the small splined shaft for quicker apply of pressure to TC clutch. - installed Corvette kickdown valve which allows for WOT shifts from 3 to 4 and then holds 4th. Stock one will ALWAYS hold 3rd forever At WOT, or kick down into 3rd at part throttle otherwise. With stock valve you never get the benefit of high speed WOT in 4th or OD. Everything is ready to go, haven't driven it yet. I just need time for the initial startup so I can add the extra fluid, then take it for a workout. Hope is has a whole new personality.
I'm afraid that thing is going to shift like you are getting rear ended by a truck. And when it hits overdrive it will be solid. I hope it is what you hoped for. If not Greg and Scott out in Weatherford at Phoenix Trans are WELL versed in 700r4. Tell em Rich with "That Black Car" sent ya.
Haha! I hope it is firm but not like the feeling of waiting for a gun to fire. I should have a chance to try it out in the next couple of days. There will be an update so stay tuned!
Whats shakin Dean, you left out a few very important upgrades, which would be first on the list then do the shift kit stuff . The Beast sun shell, heavy duty roller clutch, heavy duty sprag, no yo yo pump vane and steel ring kit i like borg warner clutches, I broke the input at the hub on the forward planet, so I got the 5 pinion planet with new thicker hub. i put 5 pionion planet in the rear too, but not totally necessary as long as you have the one with the oil slinger on it. you forgot to get the rev boost valve , get the bigger one , its the one that goes in same hole as the pr valve .500 on that u got. i would get a supper srevo not the corvet one. if using an old rev drum dont use the wide band, use the HD kevlar one. a used drum will have some dish to it so a wide band wont grab. I like a wide HD band with a NEW drum. many things to do in the input drum the gov needs a little attention,taylor the weights and springs to your rear end gear, The 1992 is a good case , i have the same yr case. with full throttle 3,4 shift capability some attention will need to be paid to the 3,4 clutch stack up. many ways to go with that, i have tried a few like the Z pack , that was ok but got mushy and burnt after a few yrs. now im using thick colen steels and 8 friction set up. make sure you dont use the radioator to cool the trans, use a seperate cooler, i put an electric motorcycle fan on mine too. make sure you have 3/8 cooler lines , 350 cars came with 5/16 lines.
Good info on the build. I am going to assemble a 4l60e for my suburban. I am wanting to be able to tow in OD. Does your recommendation for the eight clutches and kolene steels work go for this application? I was going to stack in the thickest steels I could find and how even many red clutches I could fit. I'm not sure how it would work but we know the thin steels and such fail so I was going the other way. I don't anticipate a lot of power maybe 300hp as for now it is a stock 94 350. Sorry for the highjack. Let us know how it shifts when you get it in.
Red,blue , I think those are alto they will work too. To get 8 clutches u need to have the rite apply plate, and thin pressure plate, I ended up using the pressure plate from a z pack , that was the only part that survived. For your app I go with the latest GM design that u can get , the steels will have vent holes, they will be kolean coated, I have never used colored friction( clutches) on my car but built many for others with no problems, I like Borg Warner , colored ones u need to soak in ATF , overnite. If u don't mind a little clunk when u put it in drive get that little piece of metal called a case saver, it holds the low reverse roller clutch assy in the case . i have built mine to hold up to full throttle 3,4 shift with what should be close to 600 hp in a 455 , 4300 lb 68 Rivi. The key to survival is supplying enough oil, thick steel thinest clutches, input shaft sealing, stronger return springs to stop centrifugal apply , I like superiear shift kits . Boosted line pressure, and the best cooler with electric fan u can get.
Hotrod, the tranny has just been rebuilt by a pro as far as hard parts, upgraded clutches etc. but most other parts stock. The stuff I did was just what could be done without pulling the pump and drive stack out. I dont plan to do any drag racing. Otherwise I think a Beast sun shell would be a no brainer for high torque applications. I have read other opinions that the 5 pinion planet is not much better than the 4 pinion it comes with. Anyway it would be cheap insurance if I ever have it rebuilt. I have an aftermarket aluminum radiator so I run an external cooler. I have a lazer temp gun so I will keep an eye on tranny temps and go with a larger cooler if needed. So far, even in TX summer weather it runs less than 190. I am guessing I have maybe 375-400 HP and should be around 460 TQ, so I think it should live a while, even though I do plan to hammer it pretty hard on occasion. After all it is a muscle car!
Sounds good Dean, I was just going by expiearance with the 700, Yours may survive beign in a car it was more designed for. I learned a few lessons on my own car with the 700, But my last one lasted about 8 yrs , and I hammered it every time i got in it. I would take the freeway home every nite and make it a 5 mile ride instead of 3 blocks. Funny thing about transmissions , when you get the hayden rebuilding manual, you also should get the updats manual that is just as thick.
Finally took it out for the first drive since the tranny mods and new TC. The first thing I noticed is that it idled nice while in gear. Before, the idle needed to be set at about 1,000 RPM in park, so that it would not die when put in drive, where it would struggle to idle as it dropped to about 700-750 RPM as it fought the converter. In fact I can set the base idle down to 750 now or maybe a bit lower and it will behave well at stoplights. Took it easy for about 15 minutes just ramping up speed real slow from a stop, just to be sure nothing leaked or came loose inside. After a few take-offs to let it smoothly go through the gears I started getting some confidence and hit it a bit harder. Shifts from 1-2 were instantaneous but not jarring at all. You could hear it shift, but not feel it. Like I was hoping, the 9.5" converter absorbed all the shock out of the shifts. After a few more aggressive take-offs I finally nailed it to the floor at about a 15MPH roll. It spun the wheels pretty good and then barked 'em shifting into second gear. Next I did some highway cruising. I have a toggle switch to activate 4th gear lockup. I have it set so that it will not lock up unless in 4th. The lockup felt like a shift into 5th gear, and dropped 300 RPM. Remember I had removed the check ball from the end of the tranny shaft to get a quicker firmer lock up.....so that seems to work. Then I ran up to about 65 and floored it. Only when floored did it downshift to 3rd, which is what I expected given that I changed out the kickdown valve. Otherwise it would kick down with just a little extra throttle. Before, that too easy kickdown was very annoying especially if you just wanted to casually pull ahead of another car. Good mod to make for only $35.00. When I got home I left it running while I checked the tranny temp with my lazer temp gun. Pan showed 176, line coming out of cooler showed 156. I am not assuming this will always be the case since it is 40% outside right now. I'll check it again during warm weather. Initial observation is that so far I am very happy with it. Much easier and more fun to drive. Why am I suddenly wanting more power
Thanks Rich. It is working like I want it right now. I did a lot of research on the mods, and of course almost every mod had a good opinion from one party and a bad opinion from another. But the fact it worked like I want is probably due more to luck than skill. BTW I was willing to give these mods a shot only because I have a newly rebuilt spare tranny on standby. Now we'll see how long it lasts!
what torque converter do you have, ive been thinking that is something i need to imporove, When i floored it in first it seemed to slip that is the converter seemed to slip a littleat the top
It is a 9.5" by Winners Choice. Stall I specified was 2600, but I think it stalls a bit higher. I really like it so far. Car is more fun to drive now for sure.
After 14 yrs I can't believe I have never drove a perf stall converter, are u able to put more pedal in it on take off? Does it raise ur cruising rpm
In my case it is a lockup converter, so it has zero impact on cruise RPM. It cruises at about 2400 at 70 mph. If you have a TH400 a high stall converter will raise your cruise RPM unless the stall rating is below your normal cruise RPM. Example is if you get a 3500 stall converter and your cruise RPM is 2500, it will slip more at 2500 RPM vs a stock 1600 RPM stall converter, creating heat as you are cruising. So you should get a converter that stalls a bit below your cruise RPM, so in my example a 2400 stall converter would not have noticeable slippage at 2500 RPM. Yes it can be floored on takeoff with the 9.5" converter. Since it has some stall, it allows you to take off higher in the power band, ideally where the engine is making the most torque.
Good point about the lockup converter... I had an old Chevy truck with 700r4 and I swapped in a 3000 stall converter and it really helped the truck get off the line... And then on the highway 100% lockup was great...
