Topic: Better of 2 trans?
in Forum: C3 Driveline Components
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Is the TH-400 or the TH350 a more preferred transmission and why? My 74 has a TH-400 that I will be having a shift kit installed into it on may 3rd. My engine is a 350, 195 HP. I have noticed that at times the tranny will shift to soon into 2nd gear before the rpm's can wind up. I am hoping that they can eliminate that as well.

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Moderator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20219
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
The 400 is head and shoulders above the 350 in terms of durability. They do weigh more, and take a few more ponies to operate, but in the end, there's no comparison.
The early shift you are describing is most likely caused by a bad vacuum modulator, located on the pass. side, front of the trans, just below where the cooler lines are.
Do you know what type of "shift kit" you are installing?
The early shift you are describing is most likely caused by a bad vacuum modulator, located on the pass. side, front of the trans, just below where the cooler lines are.
Do you know what type of "shift kit" you are installing?
Joel Adams
C3VR Lifetime Member #56
My Link
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
B&M makes 3 kits from what the transmission shop told me. The first one they said was a waste of money and effort. The middle kit is the one I decided to go with. He describe it as the kit most people use on the street. It will give very solid shifts but does not have to be operated manually. I didn't want to loose driveability but I wanted a shift that I can feel. I am not worried about weight so I am glad to hear that the 400 is somewhat more durable. I ask them to replace the side shift seal while they are working with it and I guess I should check the modulator as well. Does the modulator have a steel pin that goes between it and the trans when putting it in? I guess I could check it by seeing if fluid runs out the vacuum hose when removed as well?


Moderator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20219
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Yes, you can check the condition of the modulator diaphragm by removing the hose, and seeing if any fluid runs out of it.
Don't take this the wrong way(please!) but, imo...B&M stuff is crap, to put it bluntly. Yeah, it will shift better, and work better, that's not where I have an issue. My peeve is how much they charge, for what little you get. I've ranted on this subject before, so I'll not get on the ol' soap-box again...just stating my opinion, for whatever it may be worth. I've just seen too many folks shell out $75-80 for a B&M kit, and bring it to me in this huge, pretty box for me to install. When you open this huge box, you see two springs, maybe a couple of shims/plugs, some gaskets, and a page or two of instructions.
Tender this opinion with the fact that I do this every day, so I'm a bit biased.
I'm sure they'll do a good job, and you'll like the improvements.
Be sure to let us know how it goes!
Don't take this the wrong way(please!) but, imo...B&M stuff is crap, to put it bluntly. Yeah, it will shift better, and work better, that's not where I have an issue. My peeve is how much they charge, for what little you get. I've ranted on this subject before, so I'll not get on the ol' soap-box again...just stating my opinion, for whatever it may be worth. I've just seen too many folks shell out $75-80 for a B&M kit, and bring it to me in this huge, pretty box for me to install. When you open this huge box, you see two springs, maybe a couple of shims/plugs, some gaskets, and a page or two of instructions.
Tender this opinion with the fact that I do this every day, so I'm a bit biased.

I'm sure they'll do a good job, and you'll like the improvements.

Be sure to let us know how it goes!
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Manteca, CA - USA
Joined: 11/20/2005
Posts: 3623
Vette(s): 1978,two tone,Metalic Rootbeer & gold
1975 L48 4 speed
Ahhhhh ! The modulator you say. The wifes car ( TH350) does that too. I was about to try to adjust the mod. Thanks Joel, I might as well buy a new one
.

Jimmy B.
Just can't wait to get on the road again.
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in Forum: C3 Driveline Components
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