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On Topic School me on TH400

EOR1488

Well-Known Member
#1
So switching over to a TH400 from my last set up.

Ford Ranger 1450 37” Tire 4700 Lbs 500hp v8 6800 rpm 5.63 r&p

Just looking for suggestions on everything that goes along with it and the trans itself. I have talked to gearworks, Culhane, maximum etc.

I have heard a lot of opinions on builders but I’m looking for opinions on what options are a must or do you like. I’m on a little bit of a budget so where should I put money.

Larger sprag, Reid case, close ratio gears, billet tailshafts etc what is a must what can wait?

Also any suggestions on coolers I have been looking at CBR 12” running two of them? Any other suggestions or something else. Will that be enough?

Finally converters and stall speeds what suggestions? I’m on edge for 3500 or 4000 stall. My cam comes on pretty hard at 3000-6,800 pretty flat power from 3,500-6,500 530hp cam is 300/310 duration and .567/.576 max lift

Just taking any advice I can thanks guys
 

Bert is my name

Well-Known Member
#3
The 700r4 can be built to take quite a bit of abuse. The first gear in the 700 is around 4 to 1. The 400 is around 3 to 1. I believe the motor home 400 came with a straight cut 3.75 to 1 first gear. That would be the one I would use if I chose to run a 400.
 

JDDurfey

Well-Known Member
#4
When you say the 700R4 can be built to take quite a bit of abuse, what exactly do you mean. How much HP can it handle? Other than the overdrive, how much different is it than the 400? I know they are not used in racing, but what about a pre-runner with 400 hp?
 
#5
It should easily handle 400 horses. It's the torque that causes problems. The sudden loading and unloading that is common to off-road driving is where the problems occur. The 700r was run in the corvette for years.
 
#6
Heat kills them too. High stall converters will run hotter than lower stall speeds. Lower gearing will allow for a little less stall speed. I would recommend talking to a converter shop and have one built for the application instead of using an off the shelf converter like summit sells.
 

JDDurfey

Well-Known Member
#8
Didn't the 700r4 trans come behind the 6.2 and 6.5 GM diesels? I went through a number of converters and transmissions in my Suburban before I sold it. Only had it about 2 years.
 

isdtbower

Well-Known Member
#12
Reid will have a 4l80 case if not already. T400 internals plus another planetary for the OD. Someone may be making a HD version of that Planetary also. Do you need a real deep 1st gear? Careful on stall speeds with an OD unless lock-up.
 
#13
Deeper first gear will allow for taller rear gear. Taller gears have more meat to them making them stronger than a lower gear. With all other variables being the same.
 
#14
The 700r4 can be built to take quite a bit of abuse. The first gear in the 700 is around 4 to 1. The 400 is around 3 to 1. I believe the motor home 400 came with a straight cut 3.75 to 1 first gear. That would be the one I would use if I chose to run a 400.
The 700r4 can be built to take quite a bit of abuse. The first gear in the 700 is around 4 to 1. The 400 is around 3 to 1. I believe the motor home 400 came with a straight cut 3.75 to 1 first gear. That would be the one I would use if I chose to run a 400.
That would be called a turbo 475 and it came in just about all of the older cab-on-chassis applications. While it does have straight cut gears and a beefier case, thats the first I've heard of the lower first gear.
 
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