Can someone tell me how many teeth for my speedo gear '69 C20 TH400 350 w/4.10s - The 1947 - Present Chevrolet & GMC Truck Message Board Network

weim55 · 09-05-2019, 12:22 AM

The trans has been swapped at some point in my truck and I want to make sure the correct speedo driven gear is installed. '69 C20 350 w/ turbo 400 and stock 4.10 rear. Build sheet says the stock gear is "JE" code. Anyone??

Thanks,

Steve weim55 Colorado

geezer#99 · 09-05-2019, 08:32 AM

What do you mean by correct?
Correct as in original or correct as in accurate!
You’d need the driven gear teeth number too.

weim55 · 09-05-2019, 09:17 AM

Driven gear, yes. Need a starting point and hopefully the original will be correct. It currently has a 36 tooth gear. Running a stock height tire. Original tire was a 7.50 16.

Steve weim55 Colorado

geezer#99 · 09-05-2019, 09:21 AM

Maybe you could reverse engineer it.
Use a calculator found in here.

https://transmissioncenter.net/

**clay68c10** · 09-05-2019, 11:22 AM

Quote:

Originally Posted by geezer#99

Maybe you could reverse engineer it.
Use a calculator found in here.

https://transmissioncenter.net/

Yep, I’ve used that site before and ordered the right gears from them also. My speedo was dead accurate after.

jimijam00 · 09-05-2019, 10:09 PM

Here you go fellas. Allow me to post a direct link to the speedo gear calculator to make it easier for forum members to find.

http://www.bgsoflex.com/speedo1.html

09-05-2019, 12:22 AM	#1
weim55 Registered User Join Date: Jan 2017 Location: Larkspur, Colorado Posts: 916	Can someone tell me how many teeth for my speedo gear '69 C20 TH400 350 w/4.10s The trans has been swapped at some point in my truck and I want to make sure the correct speedo driven gear is installed. '69 C20 350 w/ turbo 400 and stock 4.10 rear. Build sheet says the stock gear is "JE" code. Anyone?? Thanks, Steve weim55 Colorado

09-05-2019, 08:32 AM	#2
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,668	Re: Can someone tell me how many teeth for my speedo gear '69 C20 TH400 350 w/4.10s What do you mean by correct? Correct as in original or correct as in accurate! You’d need the driven gear teeth number too.

09-05-2019, 09:17 AM	#3
weim55 Registered User Join Date: Jan 2017 Location: Larkspur, Colorado Posts: 916	Re: Can someone tell me how many teeth for my speedo gear '69 C20 TH400 350 w/4.10s Driven gear, yes. Need a starting point and hopefully the original will be correct. It currently has a 36 tooth gear. Running a stock height tire. Original tire was a 7.50 16. Steve weim55 Colorado

09-05-2019, 09:21 AM	#4
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,668	Re: Can someone tell me how many teeth for my speedo gear '69 C20 TH400 350 w/4.10s Maybe you could reverse engineer it. Use a calculator found in here. https://transmissioncenter.net/

09-05-2019, 10:09 PM	#6
jimijam00 Registered User Join Date: Apr 2009 Location: PNW Posts: 553	Re: Can someone tell me how many teeth for my speedo gear '69 C20 TH400 350 w/4.10s Here you go fellas. Allow me to post a direct link to the speedo gear calculator to make it easier for forum members to find. http://www.bgsoflex.com/speedo1.html



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