Has anyone converted to electronic speedo with TBI? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

joe231 · 03-10-2011, 11:41 AM

Has anyone converted a '87-89 TBI truck to the '90-91 speedo?
I need to convert my truck to electronic speedo. I used a newer trans with the electronic speed sensor.
What wiring do I need?
I'm going to do some junkyard scrounging and just want get everything I need.

slb1985 · 03-10-2011, 02:07 PM

if you didnt want to convert to elec. speedo you can take the tail shaft off of the trannies and swap the gear on the input shaft ( i think thats what its called)
to convert the new to mech. that is what i did i had a 700r4 from a 92 van for $50 in a pinch and its still goin and speedo is correct. I had to improvise a way to get the old gear off of new tranny, but with a BFH and c clamp it came off eventually

joe231 · 03-10-2011, 02:14 PM

Really?
Is it that simple?
I may go that route if it is...
I thought I had to swap the rear output shaft?
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slb1985 · 03-10-2011, 03:06 PM

What i did was remove the metal gear off the newer trans ( (bfh method above) and the older trans has a plastic or nylon gear on it that will slide off and on the new one... try to pay attn to where the mech gear is seated to match it the when you swap it, i just kinda eyeballed it and go lucky, and the use the mech tail shaft, bolt it up and ur good to go once you get to lookin at it its pretty straight forward. i didn't take any pics of the change over never thought i would use that info again. i hope i didnt forget something if anyone else has done this and i missed ssomething chime in

i think just to do this part of my tranny swap was maybe 15-30 min...

joe231 · 03-10-2011, 03:13 PM

Cool
Thanks for the info!
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slb1985 · 03-10-2011, 03:17 PM

Glad I could finaly help someone on the board
Posted via Mobile Device

MARKDTN · 03-10-2011, 04:15 PM

In another car I bought a Corvette 700R4 with electronic speedo output. I just swapped the driven gear and rear tail housing from an B-body 700R4 with mechanical speedo and it works fine. Now if you have a 4L60E that may not work.

joe231 · 03-10-2011, 05:37 PM

Quote:

Originally Posted by slb1985

Glad I could finaly help someone on the board
Posted via Mobile Device

Quote:

Originally Posted by MARKDTN

In another car I bought a Corvette 700R4 with electronic speedo output. I just swapped the driven gear and rear tail housing from an B-body 700R4 with mechanical speedo and it works fine. Now if you have a 4L60E that may not work.

No 4L60E here,
I looked at both rear housings and they are the same, I just didn't realize I could remove the tone ring and put a drive gear in it's place. Bowtie overdrives has everything I need for @ $80. I think I'll order it.
Thanks again for the info guys!!
Posted via Mobile Device

03-10-2011, 11:41 AM	#1
joe231 Registered User Join Date: Dec 2007 Location: Palmer, Alaska Posts: 13,821	Has anyone converted to electronic speedo with TBI? Has anyone converted a '87-89 TBI truck to the '90-91 speedo? I need to convert my truck to electronic speedo. I used a newer trans with the electronic speed sensor. What wiring do I need? I'm going to do some junkyard scrounging and just want get everything I need. __________________ *CHEVY ONLY*

03-10-2011, 02:07 PM	#2
slb1985 Registered User Join Date: Jul 2010 Location: Sandusky,OH Posts: 71	Re: Has anyone converted to electronic speedo with TBI? if you didnt want to convert to elec. speedo you can take the tail shaft off of the trannies and swap the gear on the input shaft ( i think thats what its called) to convert the new to mech. that is what i did i had a 700r4 from a 92 van for $50 in a pinch and its still goin and speedo is correct. I had to improvise a way to get the old gear off of new tranny, but with a BFH and c clamp it came off eventually __________________ 1987 R10 Silverado - Rusty But trusty Daily 1984 C10 Custom Deluxe - Newest Project

03-10-2011, 02:14 PM	#3
joe231 Registered User Join Date: Dec 2007 Location: Palmer, Alaska Posts: 13,821	Re: Has anyone converted to electronic speedo with TBI? Really? Is it that simple? I may go that route if it is... I thought I had to swap the rear output shaft? Posted via Mobile Device __________________ *CHEVY ONLY*

03-10-2011, 03:06 PM	#4
slb1985 Registered User Join Date: Jul 2010 Location: Sandusky,OH Posts: 71	Re: Has anyone converted to electronic speedo with TBI? What i did was remove the metal gear off the newer trans ( (bfh method above) and the older trans has a plastic or nylon gear on it that will slide off and on the new one... try to pay attn to where the mech gear is seated to match it the when you swap it, i just kinda eyeballed it and go lucky, and the use the mech tail shaft, bolt it up and ur good to go once you get to lookin at it its pretty straight forward. i didn't take any pics of the change over never thought i would use that info again. i hope i didnt forget something if anyone else has done this and i missed ssomething chime in i think just to do this part of my tranny swap was maybe 15-30 min... __________________ 1987 R10 Silverado - Rusty But trusty Daily 1984 C10 Custom Deluxe - Newest Project Last edited by slb1985; 03-10-2011 at 03:07 PM.

03-10-2011, 03:13 PM	#5
joe231 Registered User Join Date: Dec 2007 Location: Palmer, Alaska Posts: 13,821	Re: Has anyone converted to electronic speedo with TBI? Cool Thanks for the info! Posted via Mobile Device __________________ *CHEVY ONLY*

03-10-2011, 03:17 PM	#6
slb1985 Registered User Join Date: Jul 2010 Location: Sandusky,OH Posts: 71	Re: Has anyone converted to electronic speedo with TBI? Glad I could finaly help someone on the board Posted via Mobile Device __________________ 1987 R10 Silverado - Rusty But trusty Daily 1984 C10 Custom Deluxe - Newest Project

03-10-2011, 04:15 PM	#7
MARKDTN Registered User Join Date: Jan 2011 Location: Chattanooga, TN Posts: 2,171	Re: Has anyone converted to electronic speedo with TBI? In another car I bought a Corvette 700R4 with electronic speedo output. I just swapped the driven gear and rear tail housing from an B-body 700R4 with mechanical speedo and it works fine. Now if you have a 4L60E that may not work. __________________ '83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project Last edited by MARKDTN; 03-10-2011 at 04:16 PM.



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