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Your cart is empty.B&M 70239 Shift Improver Kit for Automatic Transmissions
Long2757
2025-09-05 12:37:30
I installed this kit in my truck (91 GMC Sierra C1500 2wd) back in 2012. Took me an afternoon and evening with a buddy helping me. We had the truck on jack stands in my driveway. I put one of these in a friends truck before but wanted to improve the lazy shifting of my truck. I used the stage 2 street strip parts. Wow. It shifts so hard 1st to 2nd that it will bark the tires which is what I wanted at like 3/4 or more throttle but because you take out the 1-2 accumulator spring and replace it with spacers you get a very harsh shift. It actually shifts too hard. Now I like a firm shift and I have put shift kits or performance valve bodies in all my automatic cars but this is just ridiculous. At very light throttle it still shifts too freaking hard. I usally let off the gas at around 12-15 mph just to let it shift to 2nd the softest it can. It shifts to hard it has caused my truck to jump from OD to N on occasion from the 1-2 shift when the shifter is in OD. The 2-3 shift is beautiful and the 3-OD shift is also fine. Just the 1-2 shift is way too hard. People ask me if there is something wrong with my transmission when they first ride in my truck. I have to tell them that I put a shift kit in this truck. I am going to try and find the box and drop the accumulator piston assembly out and replace it with the springs for the stage 1 RV/Heavy Duty springs. It definitely needs a spring to soften the shift as the spacer doesn't soften anything and it slams into gear. I tow car trailers and boats with my truck so I also added a huge trans cooler when I did the shift kit and it has towed fine and kept the trans temps nice and low. I will be adding the Corvette servo soon.
Happystains
2025-08-28 17:47:32
What can I say, these work. Have bought and installed literally hundreds, if not thousands of these over the years. Only had a single instance with Amazon where we received a completely empty paper bag mailer and no item whatsoever. Amazon did right and ship us out a replacement next day. Just wish prices would fall to about 1/3 of what they have been lately.. ahh, the good ole days :F
Cyclonova
2025-08-13 18:43:13
I used this shift kit with a stage 2 rebuild and a Corvette servo. I have an overbuilt 89 C1500 with a 350HO and burned out my transmission within months of building the motor. I bought a rebuild kit and this shift kit to help improve shift time so i wouldn't be burning out my clutches between shifts, it did that and then some. This kit shifts insanely fast and firm. It slaps 2nd gear so hard the rear end starts squealing at 15 MPH. I am 110% satisfied with how it brought my truck to life.
Blake Adams
2025-08-10 15:04:45
Part was right and trans was messed up though
Kenneth
2025-07-04 13:06:16
I really like this kit, I only used the street kit. Props better shifts, 1-2 shift is a quick hard shift. Not a down side for me, when leaving a light or stop, my truck spins tires shifting from 1 to 2nd gear. This kit will wake up your transmission.
1988c4
2025-06-14 13:56:45
If you own a 1985-1991 Automatic Corvette then you need to buy this shift kit. I spent allot of money rebuilding my engine. I increased the horsepower to 330+. Everything was great and then I looked into upgrading the transmission and found this shift kit. Recommended by Corvette owners. It gave me the most improvement from 1st gear to 2nd gear. Immediate throttle response and not a jerky shift either.
Roguelement
2025-03-04 18:00:57
As always B&M to the rescue . The kit was easy to install if your familiar with GM valve bodies ..The test drive told the story my truck had new found trany life .. thanks guys..
RLB Customer
2025-02-03 15:03:28
Easy to install. Really improves the shift.
Steve
2024-12-15 16:48:14
This item was what I had expected, and the shipping took less time to get here, then indicated.
Noid
2024-12-10 11:44:42
Quick delivery and good price, but have not attempted to fit yet
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