I have been rethinking just how good is a 200R4 behind Big block Buicks. They were designed to help a small engine move a big car and they work good in the GNs. I'm not talking about strength so much as I am about the characteristics of how they work. The one feature that troubles me most is the big down shift at lower speeds. Does the BBB with all its torque really need to go all the way back to 1st at 35 or 40 mph? The first time I floored my 53 at about 30 mph I thought the whole drive line was leaving the car and the traction was null and void as in gone. It didn't hurt anything but I wouldn't want to make a habit of it. When I want to get on it now I shift manually to me it just feels better and less worrisome. I think its time to go to the 4L80E or maybe put the 400 back in and go to a GV. Larry seems to like his setup and I just happen to have a S/P 400 in my GS. What say you my Buick friends? Bob H.
I say GV with a 400 after all we have been through with 200 4R's. Read up on the turbo forums and other places on the 200's. Tyler has broken 5 of them in his GN. They are very particular and many of the best known 200 builders have quit building them due to the troubles. He has one in the GN now and will build a TH 400 next and be done if this one breaks. Even though the GV is expensive, it will be less in the long run.
I have run a SP400 for 28 years and it is nearly bulletproof if done properly, as we all know. In a GS to put in a GV you have to do some serious work on the floor pan from what I hear and the drive shaft/trans mount are a bit of work. I have no experience with either the t200-4r or the GV but I'm giving the t200-4r a try in my car. Is there no tuning for the t200-4r to alleviate your problem condition?
Actually its the way it is designed to work. I just don't care for the big down shift when floored. With all the toque the big blocks have it seems counter productive to me.o No: Bob H.
Sounds like the tv cable needs adjustment. Or line pressure is off. Just love my 200r4s :TU: Just built one for my GS Vert with 10 in converter.:beers2:
I am confused what the actual problem is here. You are worried because your 455 was really powerful when the 2004r downshifted?
I have a 200-4R out of an '89 Caddy Fleetwood Brougham behind the 6.0 LS series motor in my '66 Skylark. The engine probably puts out about 400HP. I love the trans and found it an easy swap, but if left in OD, it will tend to shift into OD from Drive at around 35-40MPH. That's not too bad really, but then the torque converter locks up, and the car will bog and surge a bit if I slow down to below 30-35MPH. I usually just leave it in Drive, but lately when the fuse to the lockups' power blew (on the wiper curcuit) it seemed to run pretty well in OD since it wouldn't lock up. Think I may install a switch for that feature that I throw when I'm on the highway and need the feature for mileage.
No I didn't like the fact that it down shifted to far. I was driving in third gear between 35 and 40. When I floored it it shifted all the way back to 1st gear. Just a guess but I believe at 35 mph in first gear the engine is probably turning around 4000 rpms. I don't think it needs to go all the way back to 1st gear and 4000 rpms to perform and it is a hell of a jolt to the drive line. If I had a 350 or a 400 turbo and was going around 40 I wouldn't floor it and manually pull it back to 1st. Bob H.
I am using a TH200-4R Level 3 from Bowtie Overdrives. They built the correct transmission for my car (weight of car , rear axle ratio, tire size ) It is important to get the TV cable correct adjusted. I used TV Cable and TV Cable bracket from Bowtie overdrives to be sure to get the right setup. I adjusted the TV cable by using pressure gauge. (BTO says this is the only way to be sure that the adjustment is correct) The car shifts perfect. I use a toggle switch for lockup. My engine is a 455 close to stag1 specifications. Nice car you have ! http://www.bowtieoverdrives.com/index.shtml
It's downshifting because when you floor it you're telling it to get to max power NOW. If you want a less rough downshift then stop flooring it. Any trans you put in will behave the same way. You're going from cruising speed basically a bit over idle all the way to the peak of the powerband on a BBB. It's going to be a harrowing experience if you don't think before you do it. Remember this, if you decide to floor it because a runaway semi is flying up behind you at 105 mph then would you want to go to max power and launch or would you want a nice smooth granny shift? The loss of traction from 35 says alot more about your tires and suspension than it does about the trans downshifting.
There is a problem with two and 3 gear downshifts when you are in drive with a 200-4r. It is a very violent action. In general you have to be very careful with the amount of throttle applied. I think Bruce at Extreme Automatics has a valve body that corrects this. Part of the problem may be that many of use change the rear gears (mine is 3:73) and that is not a factory gear. GN's came with a 3.55.
It's because everyone goes with the hardcore GN type valve instead of using a softer one from a B-body. Switch to one of the non-race type and you'd find it to be a very smooth and soft trans. Of course then you'd complain that it isn't performance enough since it's an old lady trans at that point.
At last someone who knows what I'm talking about. I will get a hold of Bruce and see what he says. I am running 3.55 gears but have a fairly tall tire. My trans works fine and if the cable wasn't properly adjusted I would have fried it a long time ago. Thanks for the info.
You are wrong any trans will not act the same way. My GS with the 400 Turbo doesn't go all the way back to 1st when I floor it at 35 mph. And I will be on the look out for those runaway semi trucks doing 105. Do you see many of those trucks? Funny thing I'm 72 years of age and started driving truck in 1963 and never have seen one. Bob H.
You don't spend enough time driving on I-95. If you travel far enough late enough you'd be shocked at the poor driving nowadays. I've had semis fly by me while I was doing 80. Almost got run off the road by a guy in a box truck one day because my 75 wasn't fast enough for him and his heavily leaning load of trash. It's pretty scary sometimes. And I know exactly what problem you're describing on the massive downshift, I'm just more accustomed to it since I have more experience with that and the 4l60 than with any of the other trans available. The TH400 shifting with a blown modulator is alot rougher than the 2 gear downshift though. I almost ripped my shoulders out of the sockets on one of them blown modulator shifts ou:
The main problem is the difference in first gears. The 400 has a 2.48 first and the 200 has a 2.74. The 700 has a 3.06 first gear while the 4l80 can have a 2.84. So the drop to first is going to be "more violent". But if you want the best over driven trans it will be the 200 at .67 compared to 1.0 to 1 of the 400. There is no Bruce at Extreme Automatics, Just Lonnie Diers the owner. Call and leave a message telling him his good friend Mississippi Joe told you to call. He was a BBB guru way before the GN days. He knows his stuff.:3gears:
I know all about the difference in gear ratios betweeb the different trannies. I was refering to the way it goes all the way back to 1st gear when I don't think with the big torque of the BBB it really needs to. Thats all I was talking about. Even though the 400 is a little higher geared in 1st than the 700 200 350 I still wouldn't like it to shift all the way back to 1st when it isn't needed. Bob H.
Ah, I see now, and I have noticed the same thing in my car. However, with my stock 350 it probably isn't as violent, but at this power level the car hooks and books. That downshift is a little scary. :3gears:
