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TH350 to TH400

Discussion in 'The Garage' started by Topdown, Mar 10, 2003.

  1. Topdown

    Topdown 1/2 ton status

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    Well, it looks as though I am in need of a new tranny. chunked the TH350 pulling out of the driveway a couple days ago... /forums/images/graemlins/angryfire.gif So, i have been mulling over the thought of moving from a TH350 to a TH400.

    I have done a few searches in the forum archives and can find a ton of 350 to 700r4 swaps, but nothing helpful on the 350 - 400 swap. /forums/images/graemlins/crazy.gif

    Anyone want to share thier experience? Also, what is the gear ratio difference between the 350 & 400?

    Thanks!
    -Ryan /forums/images/graemlins/k5.gif
     
  2. 77fixer

    77fixer 1/2 ton status

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    I went from a 350/203 to a 400/205 and couldn't be happier. Cost about 250 for me to rebuild it with a 32 element sprag and corresponding drum. Gear ratios are very close, something like 2.52 vs. 2.48. You will also have to have to worry about mating your transfer case, driveshaft lengths, replacing the torque converter and adding/replacing the cooler. I used a 2wd 400 with the short output from a P/U. Let me know what else you need.


    Brett /forums/images/graemlins/burb.gif /forums/images/graemlins/k5.gif
     
  3. HarryH3

    HarryH3 1 ton status Author

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    I also did the 350/203 to 400/205 swap. I got the 400/205 as a unit, with the shifter and crossmember. Since the 400 is longer, I had to drill new holes in the frame for the crossmember. There's a switch that mounts on the gas pedal bracket to tell the 400 when to kick into passing gear. Wire one side to switched 12 volt power, through a 3 amp fuse, then the other side goes to the input on the side of the tranny. Measure for your new driveline lengths, then have a shop modify them for you. I had to make the front longer and the rear shorter. Now go wheelin'. /forums/images/graemlins/thumb.gif
     
  4. 77fixer

    77fixer 1/2 ton status

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    I'm glad you brought those little things up. I forgot all about that. I got my 205 from a 465, so I had to do all the mods to it as well. Because of the 400 being longer I had to modify my shifter handle in my hitch receiver with my floor jack handle as a cheater bar. I had to be very creative with the bends.

    Brett /forums/images/graemlins/burb.gif /forums/images/graemlins/k5.gif
     
  5. HarryH3

    HarryH3 1 ton status Author

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    Since my 205 came with the 400, the shifter handle was setup so that it came right up through the stock hole in the floor. /forums/images/graemlins/thumb.gif I didn't have to mess with that at all. /forums/images/graemlins/cool.gif
     

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