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Subject: Shift Kits

Original Message
Name: Jim
Date: December 08, 1997 at 10:25:33
Subject: Shift Kits
Looking for some help in picking a shift kit for a 700r4 trans. Car is street driven, 327 powered 64 Malibu, not raced, but like a firm shift when I put my foot in it.

What is the difference between a B&M TransPak and Shift Improver kits? What is the difference between B&M, Transgo, SLP, etc., prices range from 20 to 120, there must be some difference?

Anyone willing to share experience on this would be greatly appreciated.

Response Number 1
Name: Ken
Date: December 08, 1997 at 10:49:43
Subject: Shift Kits
I've used the B&M shift kit, and generally they
have three ranges to select from when modifying
the valve body: street, modified, and strip.
I chose the modified range. This range definitely
gives crisper shifts, however, it wasn't strong
enough to chirp the tires between shifts.
Recently I had a turbo 400 revamped at a
transmission shop known for setting up
transmissions for racing. Of coarse they
talked me into a full trans overhaul with
racing options. After installing it, I'll
guarentee you there is no comparision to the
tranny with the shift kit. This trans will
chirp the tires with modest accelaration. So
far I haven't found the car uncomfortable to
drive on the street. However I probably don't
put more than 500 miles a year on the car.

Response Number 2
Name: Wes Vann
Date: December 08, 1997 at 13:04:58
Subject: Shift Kits

As stated above, the kits normally allow you to recalibrate the trans for three shift different characteristics. I've used the B&M kit on the TH350 trans that I had and "set" it at the softest (taxi,cop car). I was REAL happy.

I think that if you read the fine print, you will find that the different kits allow you to manually control the trans differently. In other words, one of the more costly kits will allow you to "hold" the trans in first gear in spite of the fact that the trans would normally shift into the next gear. Don't confuse this with a "manual" valve body.


Response Number 3
Name: Jim
Date: December 09, 1997 at 08:43:49
Subject: Shift Kits
Further info: have previously installed a B&M TransPak set for Street/Strip (middle setting) in a TH400 behind a 454 and loved it, shifted like a stocker around town but felt like a 4 speed when you got into it hard. The kits for the 700r4 seem to be somewhat different, as they do not allow "hold" in a gear, that is why I am looking for help on the difference between the Shift Improver kit and the TransPak kit, also the other brands. Do not have any available shops here, so it will b ordered thru the mail. If it was a TH350 or TH400 it would be more straight forward.


Response Number 4
Name: Bob Tiley
Date: December 11, 1997 at 12:09:53
Subject: Shift Kits
The big difference between the shift kits and the trans packs are that the trans packs include new springs for the inside of the valve body which will increase your fluid pressure and make the transmission live longer. I have used the Fairbanks trans-pac and the B&M kits for the turbohydro 350 and they both cost about $60. The extra $30 will make your transmision last longer.

Response Number 5
Name: HowwlN Hubert
Date: December 11, 1997 at 18:50:43
Subject: Shift Kits
i have the Fairbanks trans-pac also in a th350 behind a lowly 307 2 barrel (soon to be replaced with a built 400) and love it for the street. set up stage 2/street. slightly firm part throttle, chirps second when u lay into it, and man what a thrill at a 5500 manual upshift. CANT WAIT TO GET MY 400 IN!!! have same kit stage 1/towing in my k20 suburban. improved mileage. This kits also allow it to downshift quicker. great when u get snuck up on. forget the $30 kit, it just raises the shift points.

Response Number 6
Name: H5O
Date: December 11, 1997 at 22:07:51
Subject: Shift Kits
The alternative to a "shift kit" is the modification of the existing spacer plate, in which certain holes are enlarged. I have a few articles from Hot Rod, and Car Craft, in which THM 350s and 400s can be upgraded with a few spacer plate modifications, in which oil flow is increased where the holes are drilled out in the existing spacer plate.

The only drawback is that the check balls are reinstalled in the same place, per OEM specs. Some valve body springs can be changed, in which Darrell Young Transmissions detailed which springs are replaced in a THM350 valvebody, along with a spring change in the 1-2 acumulator, plugging a port in the direct clutch accululator (after removing the spring), and eliminating an o-ring on the front pump.

Not too mouch is known about modifying the THM400, in which I know of enlarging two holes in the spacer plate.

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