Quick question for the tranny gurus.

BlownDime · 11-15-2009, 01:48 AM

My '92 GMC 2500's tranny shit the bed. It was a 700R4 with an electronic speedometer. I picked up a used tranny, from an '85 Silverado, which has a mechanical speedometer. Any way I can get my current speedometer working with this tranny?

dread · 11-15-2009, 02:04 AM

they make a adapter for your exact problem you might want to check one of those s10 v8 parts vendors they have what you want. Its called a signal generator

BlownDime · 11-15-2009, 05:36 AM

Can I just remove the plastic gear driven speedo cable, and slide the signal generator onto the shaft? Or would I have to swap the shafts right out?

fastr68 · 11-16-2009, 09:50 PM

if you can find the retainer body the same size style
or swap the housing from old style

but some shafts dont have means to attach gear etc

its kinda hit and miss and complicated

regardless there are adapters out there

remove housing from both trannies and check the shafts

see if parts can swap

might.

but if not then you have to debate on whether its better to buy adapter or completely gut both trannies in order to swap the shafts out.. might as well rebuild or shift kit it while you got it gutted then..

when my 700r4 in my 198k mile 91 4.3L burns up if ever ive got a super low miles TH400 with 27 spline output(3L80HD) from a 87 2wd pickup ready for it but i will have speedo issues like this as well. and i wil ahve to cut down the driveshaft since the 3L80HD is 34.5" long and 700r4 are 31.5"

but not a big deal.

but of course the 700r4 wont die since i am ready for it.. the only thing wrong with it is the TCC screwed up in it and i had to unplug it a few months ago.,

198k and still going. great..

BlownDime · 11-16-2009, 11:45 PM

I spoke to the local parts shop, they said the magnet will read the current gears. Doesn't make sense to me, since they're plastic, but I'll try it.

11-15-2009, 01:48 AM	#1
BlownDime Works too much. Age: 23 Join Date: Jan 2007 Posts: 1,327 Location: Alberta User is: OffLine	Quick question for the tranny gurus. My '92 GMC 2500's tranny shit the bed. It was a 700R4 with an electronic speedometer. I picked up a used tranny, from an '85 Silverado, which has a mechanical speedometer. Any way I can get my current speedometer working with this tranny?
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11-15-2009, 02:04 AM	#2
dread Registered User Age: 27 Join Date: Oct 2007 Posts: 194 Location: MIAMI,FL User is: OffLine	Re: Quick question for the tranny gurus. they make a adapter for your exact problem you might want to check one of those s10 v8 parts vendors they have what you want. Its called a signal generator Last edited by dread : 11-15-2009 at 02:08 AM. Reason: additional info
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11-15-2009, 05:36 AM	#3
BlownDime Works too much. Age: 23 Join Date: Jan 2007 Posts: 1,327 Location: Alberta User is: OffLine	Re: Quick question for the tranny gurus. Can I just remove the plastic gear driven speedo cable, and slide the signal generator onto the shaft? Or would I have to swap the shafts right out?
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11-16-2009, 09:50 PM	#4
fastr68 easterwabbit Join Date: Sep 2002 Posts: 713 Location: Lincoln, IL User is: OffLine	Re: Quick question for the tranny gurus. if you can find the retainer body the same size style or swap the housing from old style but some shafts dont have means to attach gear etc its kinda hit and miss and complicated regardless there are adapters out there remove housing from both trannies and check the shafts see if parts can swap might. but if not then you have to debate on whether its better to buy adapter or completely gut both trannies in order to swap the shafts out.. might as well rebuild or shift kit it while you got it gutted then.. when my 700r4 in my 198k mile 91 4.3L burns up if ever ive got a super low miles TH400 with 27 spline output(3L80HD) from a 87 2wd pickup ready for it but i will have speedo issues like this as well. and i wil ahve to cut down the driveshaft since the 3L80HD is 34.5" long and 700r4 are 31.5" but not a big deal. but of course the 700r4 wont die since i am ready for it.. the only thing wrong with it is the TCC screwed up in it and i had to unplug it a few months ago., 198k and still going. great.. Last edited by fastr68 : 11-16-2009 at 09:54 PM.
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11-16-2009, 11:45 PM	#5
BlownDime Works too much. Age: 23 Join Date: Jan 2007 Posts: 1,327 Location: Alberta User is: OffLine	Re: Quick question for the tranny gurus. I spoke to the local parts shop, they said the magnet will read the current gears. Doesn't make sense to me, since they're plastic, but I'll try it.
	[Reply w/Quote]