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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: septantrionalis on February 20, 2017, 09:42:58 am

Title: Transmission Question (TH350)
Post by: septantrionalis on February 20, 2017, 09:42:58 am

I have a 1974 Chevy K10 with the TH350 transmission and NP203 transfer case.  What would happen if I accidentally shifted from Drive to 2nd gear while doing 70 MPH?  Is that even possible?  Will the transmission let me do that?  I wouldn't do it on purpose, but that column shifter knob is so easy to hit.

Title: Re: Transmission Question (TH350)
Post by: VileZambonie on February 20, 2017, 02:25:04 pm

You could over rev the engine

Title: Re: Transmission Question (TH350)
Post by: Stewart G Griffin on February 20, 2017, 03:07:46 pm

i don't think you can downshift from D to 2 without also pulling the lever towards you?

Title: Re: Transmission Question (TH350)
Post by: Irish_Alley on February 22, 2017, 10:06:29 am

on worn shifters you can stew.

Title: Re: Transmission Question (TH350)
Post by: travisr1988 on March 10, 2017, 12:22:46 pm

That really depends on your engine speed at 70mph, on my truck 70mph in 2nd is around 4200rpm with a th350, 3.42:1 rear gears, and 29" tall tires. In my c20 that had 4.10s, th400, and 30.5" tall tires spun about 4500 in 2nd. Those numbers are from a calculator that was accurate when I had a tach.

Title: Re: Transmission Question (TH350)
Post by: Irish_Alley on March 10, 2017, 12:48:56 pm

arnt there some trans that have a safety backup just for this reason or are those just the electronic transmissions? ive never tried it with my 4l60e and dont plan to