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Old 01-31-2019, 03:37 PM   #1
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th350 electronic speedo??

I just swapped a vortec 350/th350 combo in my 1990 Chevy and now I'm wondering how I can make my speedo work. I read something about swapping the speedo sender on the 700r4 into the th350 tail housing. but im not sure if that will work. anyone done this before??

thanks, Tim
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Old 02-01-2019, 10:08 AM   #2
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Re: th350 electronic speedo??

I wasn't aware the 700R4 was ever electronic. I thought by that time it had switch to the 4L60 label. None the less here are some search results I got for you.

Also Monster transmissions has good technical links
99 Z71 (98 body style)
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Old 02-01-2019, 11:00 AM   #3
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Re: th350 electronic speedo??

I believe you can just swap the mechanical speedo sender from the tailshaft housing with your old digital one from the 700R4.

My 1988 C3500 TH400 had a digital sender in the tailshaft. I am pretty sure I swapped it over to my built 700R4 when I changed out the transmissions.
1988 GMC C3500 Dually SLE X-Cab 7.4 TH700R4 3.73 Quick Silver/Ice Blue
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Old 02-01-2019, 02:14 PM   #4
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Re: th350 electronic speedo??

my 89 700r4 is electronic speedo output at the tail shaft...i just deleted all the factory ECM and wires, i am going the other way and installing a mechanical drive (sensor conversion). along with vacuum control rather than electronic.
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