AlwaysWave

The 200r4 tranny locks up in 4th OD, and we can put a manual toggle in that will lock-up in 3rd also.

Here's my confusion. If when in 4th, I can brake and the tranny will unlock and/or go to 3rd or lower, or I can give some pedal and downshift to 3rd for passing. Now, if I put in a toggle to lock up the converter in 3rd for city driving, BTO says the converter will stay there until the toggle is manually switched off. It seems to me that when 3rd lockup is engaged, the tranny should behave like a regular 3 speed auto, no? You know, downshift and upshift like a TH400, or TH350. If not, why not? It works when 4th is engaged, why not 3rd?

If I (we) can do that, it would help a lot with the tranny heat issue.

gkull

I'm just a 700R4 person. But the reasoning behind not being able to shift into 4th with lockup on is to protect the fragil lockup clutches.

I at one time owned an Art Carr full manual 700R4. I could also hit the manual lockup toggle in any gear. With my 4.11 rearend it was like driving a clutchless 4 speed. I'm a little hard on things and that tranny only lasted one year.

So lockup in every gear can be done. If I was you I'd just install a bigger motor with 3.90 gears and then not ever worry about shifting down

EDDIEJ82

Accelerating and shifting under lockup is hard on the converter(that's where the lockup clutch is at). That's why the factory set up up for a 4th gear thing. When you brake the converter is supposed to ulock to help save the clutch from downshifting also.

If you do alot of intown driving in 3rd only it might be of some benifit to lock the converter to help with the heat problem, but under normal conditions I would say not because it will wear on the converter prematurely like George pointed out above.

If your having a heat problem go with a bigger cooler or check into one with a fan on it.

AlwaysWave

OK, let me try to clarify. If I put it into 3rd and drive across town, it will downshift and upshift as needed, but never go into 4th because I have the selector on 3rd. If 3rd will go into lockup like 4th does, then the tranny will behave like a normal 3 speed auto. My TH 400 would lock in 3rd on it's own.

When the time comes to upshift into 4th, I would flip the toggle turning off the 3rd lockup, and let 4th lockup as it is now doing.

bobs77vet

i have a 700r4...i understand what you are saying and think it would work...but why would you want this? most "normal 3 spd autos" at least the TH350 did not have lock up in 3rd.....only the later th350s had this. in fact i like having my torque converter lock up feature turned off when just cruising around town.

AlwaysWave

Because of the heat build-up and the extra rev's hurt mileage. My TH400 had automatic lock-up in 3rd. At 50 mph it was at 2000 rpm, the 200r is at 2400 rpm. The TH400 at 40 mph was at 1500 rpm, the 200r is near 2000.

The 200r does what it's supposed to on the highway, but it's a negative for in town driving.

redwingvette

I have never heard of a TH400 that had a lock-up convertor. I use my 200-4R 4th gear all the time and control the convertor so it won't lock-up unless I am drivng over 40mph (same as factory installed systems). The problem with locking up the convertor under 40mph is it causes the engine to chug much like a manual trans if you don't downshift.

Buffalo Dude

I usually leave it in 3rd for city because 4th bogs it down too much.

It sounds like something else is amiss, because 3rd for both the 200 and 400 is 1:1. It shouldn't be that much worse. Good luck.

AlwaysWave

Yes you're right, the TH400 does not lock in 3rd, my mistake. The TH400 seemed much more efficient at lower speeds than the 200r. I don't use 4th at under 40 mph, but I would like to use 3rd without the extra revs and heat. That's why I used a 1600 stall and not the 2200 stall converter BTO sent.

redwingvette

With the 1600 stall you should be the same as what you had with the TH400. My trans came with a toggle switch that would alow the convertor to lock in every gear if turned on. Only in forth if turned off. You still wouldn't want it to lock up unless yo were over 40. Painless Wireing has a system that uses a vacuum switch to keep the convertor from locking unless you are driving at a point where the vacuum is set for. That should work the way you want.