CK5
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th400 swap
- Thread starter dstang97
- Start date
If you have a 1973 to 1988 truck, you could use the factory switch, which mounts to the accelerator pedal bracket and wire it in series from the fuse block to the transmission. That is pretty much how the factory does it.
drive shafts diffrent.
tcase input gear diffrent.
possible crossmember diffrent depending on the tcase to tranny adaptor you get.
posssible shifter hole off position for tcase.
kick down wire feeds 12v to tranny plug when passing full throtle
but all of these basic fixes.
tcase input gear diffrent.
possible crossmember diffrent depending on the tcase to tranny adaptor you get.
posssible shifter hole off position for tcase.
kick down wire feeds 12v to tranny plug when passing full throtle
but all of these basic fixes.
Yeah I have a parts truck with a 400 205. The only thing im not sure of is the kick down. Can I hook up the wire from my 700r4 to my 400. I think it is for the 700r4 to shift from 1st to 2nd
700 is cable kick down.
just pull the 400 pedel switch and fallow the wire to the fuse block. then swap it over. super easy.
just pull the 400 pedel switch and fallow the wire to the fuse block. then swap it over. super easy.
Umm, no.
The 700r4 wiring controls the torque converter. I don't think the 700r4 wiring has anything to do with throttle position.
What he said.SweetK30 said:
wayne
3/4 ton status
I will tell you this after doing the 700r4 to th400 swap in 2 of my K5's. It sucked for a everyday driver. The 700r4 first gear was way nicer. Also the first swap was a 400/205 and the amount of low range lost was horrible. The current one I run a 400/241 combo and low range is better but still not enough for crawling. Yes the th400 will take some serious abuse but so will a well built 700r4. I didn't hook the kickdown up to either and the current set up has been in since 2003 with no issues. I just wanted you to know what to expect after doing the swap.
I did this swap last year. I took the 700r4 out of my 84 blazer and stuck in a th400. I loved it myself. I also have a writeup on it if you do a search. the wire will come from the th400 and go to a kickdown switch that bolts to your accelerater pedal. the other end from the switch will go to a hot in your fuse box. your front shaft will work fine but your rear shaft will not bolt up to the 205 tcase. your rear shaft would work if you got a 208 from a th400. I dont think the 208 case from your 700r4 will bolt up. the crossmember from your parts truck will bolt up to you frame, but redrilling mount bolts might be needed. If your th400 came from a gas engine, you can use the torque converter with it. if not you will need to use a different torque converter. I would not consider using the one from your 700r4 if the tranny is toast because the torque converter in it might be toast or be contaminated with the toasted fluid.
wayne is right, about your low end on the trails it will change.
I liked the th400 in my blazer because I had 373 gears and drove it on the highway alot. I usually cruised at about 2500 rpms at 65 with 35s.
wayne is right, about your low end on the trails it will change.
I liked the th400 in my blazer because I had 373 gears and drove it on the highway alot. I usually cruised at about 2500 rpms at 65 with 35s.
