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TH350 Transmission in a SyTy

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  • TH350 Transmission in a SyTy

    I wanted to post this for informational purposes because I do get alot of questions about doing the Turbo350 in the Syclone

    First of all just to answer the main question, yes you lose overdrive and yes you lose torque converter lockup. You might be able to retain lockup if you get your hands on a th350c, but I couldn't begin to tell you what's involved with setting that up. Might be easy, might be extremely difficult. I just don't know.

    If you drive your SyTy alot on the highway, you probably won't love this conversion. Personally, unless I'm driving to the drag strip or I'm out logging/tuning/troubleshooting, I drive dragstrip only about 90% of the time.

    You will re-use:
    1. Your front driveshaft
    2. Your rear driveshaft
    3. Your transmission crossmember
    4. The adapter between the 700r4 and the tcase
    5. The transmission mount (replace if its old, energy suspension makes a good one)

    You will buy:
    1. A new th350 transmission. You want a 2wd one with the 6" short tail shaft.
    2. A torque converter of your choice
    3. An Advance Adapters part #50-8506 tailshaft adapter
    4. A th350 transmission dipstick
    5. Highly recommend a th350 overflow/burp tank. The breather has a tendency to puke if you get your trans hot or you fill too quickly/overfill

    Notes about installation:
    1. I've heard you can re-use the stock shifter, but I did a new B&M shifter so I can't help with that portion of the installation.
    2. The hardware from the advance adapter you buy will be of no use to you. You'll need to go get bolts that are longer to attach the adapter and the transfer case adapter to the transmission.
    3. Once you assemble all of these together you'll have to cut the tailshaft down about 1.5 inches. I used a 4" angle grinder and a cutoff disc. I taped over the shaft and marked the length. I made my cut by just cutting from the top-down and occassionally rotating the shaft. At the end I had just a tiny nipple of metal in the middle so I could break it off and grind the little point part flat. After that, a flappy wheel in the same grinder to deburr the end. Afterwards just make sure that the tcase slides on all the way with no resistance.
    4. Installation is just the same as the 700r4. Jam the thing in and bolt it up.
    5. Your TV cable is now useless, take it out, throw it away or burn that stupid thing.
    6. If you have a transmission with a normal valve body, you'll have to supply a vacuum source from the intake manifold for the kick-down. I went full manual vb, so I didn't need it.

    Pictures for goodness

    Trans w/adapter mocked up

    Burp tank