Upgrading From TH 400 to ???
Drifting
Joined: Dec 2004
Posts: 1,714
Likes: 42
From: Austin Texas
Drifting
Joined: Dec 2004
Posts: 1,714
Likes: 42
From: Austin Texas
Yes it has over drive. Go back to the link I gave you in your first reply. It has lots of pictures and some very informative links in it that are essential reading for this transmission. It will give you a good central place for sources of information on this subject.
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Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Either the 700R4 or the 200-4R will do the job. But, the 200 will be a direct fit in place of the THM-400. You can use the same rear crossmember and driveshaft that you now have. Those would have to be changed, if you go with the 700R4.
I went the 700R4 route for my 400 equipped '71, and wish I had gone with the 200.
I went the 700R4 route for my 400 equipped '71, and wish I had gone with the 200.
Thread Starter
Racer
Joined: Apr 2012
Posts: 340
Likes: 37
From: Plymouth, Ma
Thanks for your time and info, 7T. Mind telling me why you wish you went w/the 200? Is it a smooth trans, does it have punch off the line and an OD?
Do you know how low first gear is. (I'm looking for the best if both worlds)
Happy Holidays,
Bob
Do you know how low first gear is. (I'm looking for the best if both worlds)
Happy Holidays,
Bob
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
For durability and 'guts', it's hard to beat the THM-400. But, it is very wasteful with lots of parasitic losses and really poor mileage at highway speeds. A properly built 200 or 700 will perform just as well, but will be much more efficient...25% or better mileage at highway speeds with the lockup clutch operational.
For lockup operation, you can purchase a lockup controller so that its function is completely automatic; OR I can provide you with the circuit for a low-dollar alternative that works well, is safe, and will cause the lockup function to drop if brakes are applied. I experimented and came up with a rather nice solution for mine.
For lockup operation, you can purchase a lockup controller so that its function is completely automatic; OR I can provide you with the circuit for a low-dollar alternative that works well, is safe, and will cause the lockup function to drop if brakes are applied. I experimented and came up with a rather nice solution for mine.
Thread Starter
Racer
Joined: Apr 2012
Posts: 340
Likes: 37
From: Plymouth, Ma
For durability and 'guts', it's hard to beat the THM-400. But, it is very wasteful with lots of parasitic losses and really poor mileage at highway speeds. A properly built 200 or 700 will perform just as well, but will be much more efficient...25% or better mileage at highway speeds with the lockup clutch operational.
For lockup operation, you can purchase a lockup controller so that its function is completely automatic; OR I can provide you with the circuit for a low-dollar alternative that works well, is safe, and will cause the lockup function to drop if brakes are applied. I experimented and came up with a rather nice solution for mine.
For lockup operation, you can purchase a lockup controller so that its function is completely automatic; OR I can provide you with the circuit for a low-dollar alternative that works well, is safe, and will cause the lockup function to drop if brakes are applied. I experimented and came up with a rather nice solution for mine.
That said.....What is a lock up clutch, and it's purpose?
Bob
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The standard convertor for an automatic transmission does not have any mechanism for a direct connection between the convertor pump (connected to the engine output) and the convertor turbine (connected to the input shaft for the transmission). Thus, there is slippage between them, as it is only a "fluid" coupling.
The lockup clutch is a hydraulic clutch that connects the pump to turbine directly, thus eliminating that loss of efficiency in the fluid coupling.
'Overdrive', on the other hand, is an additional gear ratio in the transmission that exceeds a 1:1 ratio (input to output). Most overdrive transmissions have a .67 or .70 final ratio. Some manual 6 speed units even have two overdrive ranges: one at about .80 and one at about .60. Some high-end European cars may have automatics with two overdrive ranges, also.
The lockup clutch is a hydraulic clutch that connects the pump to turbine directly, thus eliminating that loss of efficiency in the fluid coupling.
'Overdrive', on the other hand, is an additional gear ratio in the transmission that exceeds a 1:1 ratio (input to output). Most overdrive transmissions have a .67 or .70 final ratio. Some manual 6 speed units even have two overdrive ranges: one at about .80 and one at about .60. Some high-end European cars may have automatics with two overdrive ranges, also.