auto trans questions

**Alss** · #1 03-23-2009, 05:35 PM

Drove my Malibu finally this weekend..the TH 400 sucks!! short shifts..never lets the motor wind up..and the 3 31 gears dnt help at all

..considering a newer electronic 4 speed auto..I can still get it installed before the season starts..but which one..700R4 or 4L60/80..needs to be solid as I plan on upgrading the motor at some time. Thanks

ALbert

mfchassisworks · #2 03-23-2009, 06:34 PM

The 700R4 and the 4L60 are the same transmission, it uses a TV (throttle valve) cable to determine the shifts up and down based on throttle position. A 4L60E Is the same transmission but electronically controlled with solenoids. It needs a computer to pull info from a TPS and Speed Sensor to determine the shifts. Both are based loosely on a Turbo 350 internally and externally. A 4L80 and 4L80E are based loosely on a Turbo 400. The E at the end means it is electronic. Much like a Turbo 350 vs 400 , the 4L80's are designed to to withstand more torque ie: diesel applications. For a street car any of them will work behind a bbc. The 700R4 is the least complicated to install and a manual switch would be used to lock up the torque conv.

Chevy454 · #3 03-23-2009, 06:45 PM

[ QUOTE ]
Drove my Malibu finally this weekend..the TH 400 sucks!! short shifts..never lets the motor wind up..and the 3 31 gears dnt help at all

..considering a newer electronic 4 speed auto..I can still get it installed before the season starts..but which one..700R4 or 4L60/80..needs to be solid as I plan on upgrading the motor at some time. Thanks

ALbert

[/ QUOTE ]
Al: any idea what your current THM400 is out of? Sounds to me like you need to tweak your governor...

**Alss** · #4 03-23-2009, 08:37 PM

[/ QUOTE ]
Al: any idea what your current THM400 is out of? Sounds to me like you need to tweak your governor...

[/ QUOTE ]

lots of responses regarding the governor(not Schoney!

) and a kit is on order from summit..thanks for the replies/suggestions/info.

Tom, th400 is out of a chevelle less than 1k miles..owner switched to a M-22..B$M holeshot converter..mild shift kit

ALbert

Chevy454 · #5 03-23-2009, 08:47 PM

[ QUOTE ]

Tom, th400 is out of a chevelle less than 1k miles..owner switched to a M-22..B$M holeshot converter..mild shift kit

ALbert

[/ QUOTE ]
Was it in *semi* original condition...ie, what was it's original application, and had the governor ever been monkied with? Other than the B&M kit, you can grind down the ears on the stock governor to raise the shift points...there's an article floating around on the internet from the Buick GS club with pictures on where/how much to gring & how to adjust your governor. A 400thm is quicker when shifting itself than when being manually shifted by the driver [assuming the governor is still in place]...

**mockingbird812** · #6 03-23-2009, 09:42 PM

ALbert,

My friend down the road, that I have recommended before, should be able to help you. He knows GM trans very well, particularly the TH400. He is retired from the GM Proving Grounds and has a well equipped shop at his home. He can provide advice or do work from stock to over-the-top, high torque applications (north of 900 lb ft). He has helped others on the our board before and is currently building a trans for one of our fellows. Good people. Straight shooter.

Call Rick Annis at 480.987.3756

**markjohnson** · #7 03-23-2009, 11:21 PM

My advice would be to keep the Turbo 400. They've been around forever and are pretty servicable, no matter what the problem. I like them but I have some fast friends that just hate them. They say they're heavy and eat up a lot of horsepower. I remember Hot Rod dyno testing all three popular GM trannys a long time ago and reporting that the TH400 sucked up 50 HP, the TH350 was 36 and the Powerglide was only 18. Rob, I've never heard about TH400's shifting faster when left in Drive than being shifted manually. That's pretty interesting. I've always wanted to play around with governor weights and get 6000-6200 RPM upshifts. That'd be fun running 10,11 or 12 second ET's with BOTH hands on the steering wheel!

Chevy454 · #8 03-23-2009, 11:38 PM

[ QUOTE ]
Rob, I've never heard about TH400's shifting faster when left in Drive than being shifted manually. That's pretty interesting. I've always wanted to play around with governor weights and get 6000-6200 RPM upshifts.

[/ QUOTE ]
It gets WAAAAY over my head in a hurry, but it has to do with a synchronized shift & the bands [low reverse, coast, etc] having to engage then disengage when a governor is in place & it's shifted manually...

JoeG · #9 03-24-2009, 01:18 AM

[ QUOTE ]
My advice would be to keep the Turbo 400. ...

[/ QUOTE ]

This is my lousy opinion also--- Also go ahead and first try your new governor..

I had my 400 rebuild ..one of my better moves..

**Mr. Chevy** · #10 03-24-2009, 10:55 PM

Plus you can nuetral drop/slam that Turbo 400 into gear and it will hold up like a tank!!

Rich

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