GOING INTO GEAR HARD

Drivetrain discussion including Transmission, Differential, Driveshaft, and related items.
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Hzgray
Posts: 90
Joined: Fri Sep 09, 2016 8:04 pm
Location: Old Dominion

GOING INTO GEAR HARD

Post by Hzgray »

My car goes into gear (auto) hard with a clunk. The car is tuned with BTR stg 1. It particularly occurs after first start in the morning when I put it into reverse (car is still cold). I just changed out my diff to a 3.27 yesterday with BMR pro bushings and noticed it much more. I still need to get my tune recalibrated to take into account the gear change. I thought the "retune" was just to recalibrate the speedo. Is this just a fact of life to deal with wrt performance tune and hard diff bushing installed or will the new tune accounting for the newly installed 3.27 help resolve this clunk? Thanks.
2013 9C3, DoD delete, BTR Stg 1, Kooks 1 7/8, Rotofab, 3.27 Diff, VMR 810 wheels (staggered), King Springs (lowered), oh and a D1SC.
Silversled
Posts: 270
Joined: Fri Aug 12, 2016 7:13 am
Location: Tampa, FL

Re: GOING INTO GEAR HARD

Post by Silversled »

If all you changed was the diff and the hard bushings that's your answer. If it used to go hard into gear but it's just worse now, your tuner most likely deactivated all of your transmission torque management subsystems including garage shift torque reduction. TM is useful in making certain operations like garage shifting more "acceptable". TM should be tuned not just turned off. I usually let TM do its thing for garage shifts and coastdown shifts so it doesn't "slam" the gears when it's not necessary. I would talk to your tuner about it. If he/she only knows to turn it off find another tuner.
2014 Chevrolet Caprice PPV
2014 Chevrolet Stingray Z51
2016 AMG C63
2015 BMW X5 iDrive 50i
Hzgray
Posts: 90
Joined: Fri Sep 09, 2016 8:04 pm
Location: Old Dominion

Re: GOING INTO GEAR HARD

Post by Hzgray »

Thanks! I'll ask him about it tomorrow. The transmission tune is magic to me right now. I'll try and find some info and read up on it tonight.
2013 9C3, DoD delete, BTR Stg 1, Kooks 1 7/8, Rotofab, 3.27 Diff, VMR 810 wheels (staggered), King Springs (lowered), oh and a D1SC.
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