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Will transmission swap cause no speedometer

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Oleachea

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I have a 1990 suburban with a 700R-4 and a 208 transfer case. I ruined the transmission rear axle and transfer case. I'm going to have some one put in a turbo 350 with a 205. And was told by the guy doing it that the 700R-4 was an electronic set up and the 350 was a manual set for the speedometer. I was told I could buy a kit to make it make it work. So my main question is, is this true and if it is where do I buy this kit and what's it called.
Oh and does the Turbo 350 have overdrive?
 
Yes it is true you will have to convert your electronic speedo but I am not sure where to get the kit. The TH350 doesn't have an overdrive. I would make sure your drive shafts will work with your new set up. (right length, right joints, etc.)
 
Yeah it will all line up I had the 700R-4 rebuilt so he's taking that for labor and $500 for his drive train. Do you think that if I just bought a manual speedometer and replaced it with electronic one or would I have to run new stuff?
 
If you run the TH350 you will need a mechanical speedometer, you should have an electrical speedometer now. You can buy a converter tor the TH350 to work with your current speedometer, if I understand you currect.
 
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You had an NP241, and the speedometer/VSS is driven off of that, it has no bearing on what transmission is in front of it.

To keep the injection (and speedometer, and cruise, and ABS) working as designed, you'll need to get a VSS signal generator (40 pulse per revolution of output shaft) and connect the two wires under your truck now just hanging there to that, rewire the interior to work with the earlier speedometer/VSS (which won't feed the ABS), or get another NP241 from '90-91.
 
Well theres not really any replacements handy for my truck so I gotta for the turbo 350
 
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Well, you might be able to get some ideas from jagsthatrun.com's website.

They even posted an excerpt from their book on VSS, might be an interesting read for you, just to get an idea what you are dealing with.

I think they call them VSS signal generators, problem is, you HAVE to have the 40 pulse per revolution setup, most of the other generators are probably 2-4000pulse per mile, which is not what your setup is looking for from the speedometer cable/VSS on the t-case. This is all a bit difficult to deceipher when looking on sites like JTR, as cars and trucks were totally different in this regard, for whatever reason, so you can't take all on the 'net as gospel in regards to VSS.
 
All 2wd stuff. As mentioned, it's going to have to be a replacement for your speedometer gear, or inline, driven by the existing speedometer components in the transfercase output shaft.
 
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