Twilightoptics
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Feb 26, 2025
- Join DateFeb 2000
- LocationSeattle, Washington
- Posts:1,170
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- Car'87 IROC-Z/'82 RX7
- EngineSBC 355/1.1L Rotary
- TransmissionT56/5 Speed
- Axle/Gears4.33/3.93
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Gonna put a shift kit in my 700R4. Lots say Transgo, and I've heard lots say B&M. Guy at the performance store said they are basically the same.
Well which to go with, and how hard is each one to install?
Well which to go with, and how hard is each one to install?
Supreme Member
Having owned a Transgo commercial kit (#700) and a B&M Transpak, i'd say get the Transgo if it's in your budget. The Transgo comes with a servo assembly and is very installer friendly. The B&M Transpak comes with about 10 parts and the install book is a little vague. The Transgo is about $125 and the B&M is about $55.
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I'd recommend the trans-go anyday.... as B7M never made a shift kit and is also flawed.
If you must go with B&M for some reason, Install it as the heavy duty setup (usuing the heavier accumulator springs instead of blocking them solid. Also toss the 1/8" drill bit in your toolbox and drill the hole .70" (NOT .125"!!!) I forget offhand what # size bit it is, check a machinists chart on drill sizes.
It would also be a good time to install the GM 'B' Fix kit to allow 4th gear WOT upshifts if your car isn't already equipped.
If you must go with B&M for some reason, Install it as the heavy duty setup (usuing the heavier accumulator springs instead of blocking them solid. Also toss the 1/8" drill bit in your toolbox and drill the hole .70" (NOT .125"!!!) I forget offhand what # size bit it is, check a machinists chart on drill sizes.
It would also be a good time to install the GM 'B' Fix kit to allow 4th gear WOT upshifts if your car isn't already equipped.
Supreme Member
First, a little history. The name Shift Kit is a registered trademark of TransGo. TransGo was started in 1959 with the intention of finding the causes of complaints and failures in a particular transmission and converting that info into a kit that could be installed in the tranny.
You would be surprised that a true Shift Kit does NOT make hard shifts and is intended for passenger car and light truck use. They spend sometimes years researching a tranny to see what it does right and what it's weak points are before they can finally offer a Shift Kit for it. They also make a Reprogramming Kit which uses the Shift Kit for a particular tranny and adds HP/HD capability, and yes firmer shifts too. They generally speaking will give you the ability to select any lower gear or hold a gear to any speed with the shifter.
B&M and the like, on the other hand always have the same goal in mind: Hard Shifts. To accomplish this they have a set formula that gets applied to every transmission. A) Block or limit the smoothing devices (accumulators). B) Jack up the line pressure. C) Hog out the feed holes. The result is always hard shifts. That often has nothing to do with WHY a tranny fails and is more a RESULT of another problem causing soft, slipping shifts.
You would be surprised that a true Shift Kit does NOT make hard shifts and is intended for passenger car and light truck use. They spend sometimes years researching a tranny to see what it does right and what it's weak points are before they can finally offer a Shift Kit for it. They also make a Reprogramming Kit which uses the Shift Kit for a particular tranny and adds HP/HD capability, and yes firmer shifts too. They generally speaking will give you the ability to select any lower gear or hold a gear to any speed with the shifter.
B&M and the like, on the other hand always have the same goal in mind: Hard Shifts. To accomplish this they have a set formula that gets applied to every transmission. A) Block or limit the smoothing devices (accumulators). B) Jack up the line pressure. C) Hog out the feed holes. The result is always hard shifts. That often has nothing to do with WHY a tranny fails and is more a RESULT of another problem causing soft, slipping shifts.