Ashyukun Reader
Nov. 15, 2012 12:25 p.m.

As far as I know, there's nothing wrong with the THM-350 that came out of (and will be going back into for the Challenge) my El Camino. It will be sitting behind the 350 SBC which I've been working on souping up and in front of the 3.08-geared Posi rear that I'll almost certainly be using. However, since it's presently out of the car anyway, I figured that I should do any work on it that needs to be done before it and the engine get put back into the car.

One of the major things I'm considering and would like input on is whether to get a shift kit to improve the shifts and let me push the engine to higher RPMs before it shifts (a MAJOR problem I had with the Fiero's THM-425 this year on the drag strip...). A TransGo 1-2 shift kit for it would be about $50 (http://www.summitracing.com/parts/trg-350-1-2). Has anyone used this before, and is it worth it? Does it cause any issues in driving the car on the roads and not on the strip?

Ranger50 UltraDork
Nov. 15, 2012 12:57 p.m.

I would paper and rubber kit, sub-$20 plus labor, the internals along with the shift kit, an adjustable vac mod, and taking some weight off the governor weights along with different springs.

44Dwarf SuperDork
Nov. 15, 2012 1:38 p.m.

Call Burt Brown http://www.burtbrownracingtrans.com/ Buy your kit from him and it will do what you ask.

Nov. 15, 2012 7:37 p.m.

Would a manual valvebody be worth it? Can it be done cheaply? You still bang gears, but no clutch to set up and you already have the transmission. What do you think, Ranger? I know diddly about transmissions.

Kenny_McCormic HalfDork
Nov. 15, 2012 7:55 p.m.

Going manual valvebody means getting a better than stock shifter or risking slapping the lever, a bit too hard and blowing the engine through the hood when you miss 2nd and end up in 1st.

novaderrik UltraDork
Nov. 15, 2012 8:24 p.m.

a good shift kit is always a good idea on a TH350- and most of them allow you to tune the harshness from "nice and firm" to "holy crap, did i just break another u-joint?" pretty easily..

a good one will allow you to have full manual control when you want- upshift and downshift whenever you move the shifter, or just leave it in "D" and let the trans figure it all out for you.

Ashyukun Reader
Nov. 15, 2012 9:44 p.m.

In reply to novaderrik:

So, it sounds like it's worth the slight budget hit. Though I'm not sure I'd be using it, I actually have a ratcheting floor shifter that was in the Fiero when I got it that I replaced with a stock shifter since the aftermarket (I think it's a K&N...) shifter wouldn't put it into any forward gear except 'D'... which would have SUUUUUCKED if I had not replaced it given the issues I had on the drag strip. I haven't decided if I'm sticking with the column shift or want to FMV that thing and use it instead, though it would also require getting a cable to use it.

Can the shift kits be set up such that putting it into '2' would still behave normally, i.e. drop down to 1st when necessary and then up to 2nd? That's what we've done the last two years on the Autocross so that it doesn't go up to 3rd and keeps the RPMs up, but don't have to shift between 1st and 2nd manually.

novaderrik UltraDork
Nov. 16, 2012 5:46 p.m.

every brand will be a little different- i think they are fully automatic up to whichever range you put it in, but i might be wrong.. i haven't owned anything with that trans since i took the stock one out of my 74 Monte Carlo in the summer of '05 to swap in a 700r4, and haven't actually put a shift kit in one for probably 15 years. but they always have different ways to "tune" the shift and how it operates. i used B&M and i think TCI kits back in the early 90's because that's all there really was, but there are a lot of other choices these days.

Ranger50 UltraDork
Nov. 16, 2012 7:05 p.m.
Ashyukun wrote: Can the shift kits be set up such that putting it into '2' would still behave normally, i.e. drop down to 1st when necessary and then up to 2nd? That's what we've done the last two years on the Autocross so that it doesn't go up to 3rd and keeps the RPMs up, but don't have to shift between 1st and 2nd manually.

IF I remember right, yes it will upshift at your desired shift point based on the governor weights and springs plus anything done to the valvebody. It will NOT downshift though until nearly stopped again, slow enough to cause a regular downshift, or the lever is moved back to first.

If I find one, I'm doing a craptastic 4L60 minus the E. Going to run it full manual for absolutely nothing cost wise and a pinned PCS control valve set to 200 psi or so. That should be a fun ride.

novaderrik UltraDork
Nov. 16, 2012 9:14 p.m.
Ranger50 wrote:
Ashyukun wrote: Can the shift kits be set up such that putting it into '2' would still behave normally, i.e. drop down to 1st when necessary and then up to 2nd? That's what we've done the last two years on the Autocross so that it doesn't go up to 3rd and keeps the RPMs up, but don't have to shift between 1st and 2nd manually.

IF I remember right, yes it will upshift at your desired shift point based on the governor weights and springs plus anything done to the valvebody. It will NOT downshift though until nearly stopped again, slow enough to cause a regular downshift, or the lever is moved back to first.

If I find one, I'm doing a craptastic 4L60 minus the E. Going to run it full manual for absolutely nothing cost wise and a pinned PCS control valve set to 200 psi or so. That should be a fun ride.

a 700r4?

Ranger50 UltraDork
Nov. 16, 2012 9:27 p.m.

In reply to novaderrik:

No, a 4L60E. You can make them full manual and with a pinned pressure control valve to eliminate the computer for "no" money. I think you "lose" either lockup or OD or maybe both, but you can put those on toggle switches.

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