Transmission issues - - 5th Generation Camaro Enthusiasts
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post #1 of 4 Old 10-02-2011, 12:17 PM Thread Starter
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Transmission issues

Ok, this thread is for a friend of mine with a 68 ss. His TH350 just shot craps so he are looking into a TH400 or a 700r4. He is leaning towards the 700r4 but has no idea how much work would go into swapping that in (and neither do I). Anyway, how hard would it be? Would he need a new drive shaft? What stall would you recommend? Would there be any advantages to a TH400 over the 700r4? Any advice would be appreciated, its his baby and he wants to get it running again.
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post #2 of 4 Old 10-02-2011, 05:15 PM
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His best bet is to talk with a reputable trans builder and discuss directly with them what he wants out of the trans (daily driver vs drag racer etc), what his HP levels are (and will be down the road) etc etc.

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post #3 of 4 Old 10-04-2011, 01:35 PM
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It all depends on what he wants out of his 68 Camaro. The biggest difference between a TH400 and a 700R4, is the fact that the 700R4 is an overdrive. The 3rd and final gear in a TH350 & a TH400 is a 1:1 gear ratio. That's the same gear ratio as 3rd gear in the 700R4; but here's the difference, 4th gear is a .70:1 ratio. In short, his RPM's will drop by 30% when he shifts into 4th with the 700R4.

However, there are drawbacks. 1) The 700R4 is weaker than a TH400, so if plans to do a lot of drag racing, odds are, he's going to break it. 2) The cross member and the driveshaft are different, but that is virtually simple things to replace. 3) The shift pattern will be different. Another words, if he's running a factory floor shift car, the shifting mechanism was only designed for a 3 speed, not a 4 speed. When he manually shifts it to the lowest gear, the transmission will only be in second, not first. Hope that makes sense.

As for the stall converter, that depends entirely on your engine, and the camshaft that is in the engine. A stall is only good, if it's needed, otherwise, you're throwing your money away.

Hope any of that helps you.....
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post #4 of 4 Old 10-04-2011, 05:16 PM Thread Starter
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Thanks for the info, he took it to a shop and they are rebuilding his TH350. That was what he could afford. I'll keep that all in mind though since I'm looking around for a 1st or 2nd gen camaro now
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