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205 Output housing mod 4L80E

MEK5

MEK5

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The 205 electric speedo output housing is just about impossible to find as it was only used in the 91 CC.
One just sold on ebay for $400.:eek1: To rich for me!

I converted a gear drive over using NP241 sensor and trigger wheel and it wasnt that hard,took about an hour to plan the job and a hour to complete.

Match the width of the trigger wheel to your speedo gear width(critical measurement as this effects backlash)

Drill housing square to mating surfaces 11/16" for a 3/4" -16 thread for sensor

Spotface min. of 1 1/4" for the sensor to tighten against and also set sensor/wheel gap.

Cut off old speedo connector and dig out seal then tap hole for a 7/16 fine allenhead bolt to act as a plug or find a plug with a 7/8-18 thread
(Goodluck)

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So the reluctor ring for the 241 is a different width than the 205 one?

I'm assuming the 241 reluctor is discontinued, although I haven't checked.

$200/hour, figure that was worth it? :)
 
dyeager535 said:
So the reluctor ring for the 241 is a different width than the 205 one?

I'm assuming the 241 reluctor is discontinued, although I haven't checked.

$200/hour, figure that was worth it? :)
Click to expand...

The 241 ring mic'd 1.400 and the 205 plastic gear was 1.150,I took an 1/8" from both sides.This should be done on a lathe/mill,the gear appeared to be hard but turned easy.

That ring/sensor was used in all the GM 241s pass/driverside drop and should still be able to get them but plenty used cases in the junkyard probably cheaper than the 2 parts new!
 
I've got a spare 205 VSS setup in my garage, I'll have to compare it to your measurements.

I would have thought GM to use the same piece 241 to 205, but if it sets backlash, maybe not. Apparently GM didn't change the output shaft of the 205 to accomplish this, so the reluctor ring must be different.

The VSS itself I've compard to an S10 unit (but haven't bothered cross referencing) and they appeared identical.
 
I have the 205 tone ring in the garage, I could measure and see what it is. The VSS sensor is the same for S-10s, trucks, K-5s, burbs, pretty much anything GM 4wd.....One of these days I'll get mine done.....
 
b454rat said:
I have the 205 tone ring in the garage, I could measure and see what it is. The VSS sensor is the same for S-10s, trucks, K-5s, burbs, pretty much anything GM 4wd.....One of these days I'll get mine done.....
Click to expand...

If your tone ring is from a 205 it should be 1.150 + or - a couple thou.

It would not surprise me if S-10 ring and sensor is the same thing!
 
Problem is, if the ring was the same as anything else used more commonly, I'd imagine it to be more readily available.

I didn't know the 205 VSS setup was that valuable.
 
Nice work, but you can buy a VSS that goes where the speedometer cable would normally for $70 or so.

Andy
 
realsquash said:
Nice work, but you can buy a VSS that goes where the speedometer cable would normally for $70 or so.

Andy
Click to expand...

How about some more info about the VSS?
 
MEK5 said:
How about some more info about the VSS?
Click to expand...

Here's the bible of VSS stuff from Jags that Run:

http://www.jagsthatrun.com/Pages/SpeedSensors_Speedometer.html

I have used the 4 pulse model (4000 pulses per mile iirc) when I used a 7730 ECM on my 454 EFI and it worked great. On my Vortec swap I am not using a VSS at all. I am not sure of your application here, but the newer stuff used a much higher resolution (the 40 tooth one you are using) and if you are running a C3 or P4 ECM that isn't going to work. I had a hard time finding a 40-tooth replacement that would bolt onto the mechanical speedo cable output on the NP205 so I'm seeing how life is w/o it on the Vortec swap. I know it was a nice addition to the 7730 setup I had on the other truck.

Andy
 
Jimbo* said:
Excellent work MEK5, thanks!

If anyone's interested, the same seller has the elusive 4L80E/205 adapter up for sale on ebay right now.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=003&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=130113875412&rd=1,1
Jimbo
Click to expand...

I was watching this auction and was the high bidder on one auction but the reserve wasn't met. The reserve is over $200 and I'm not willing to pay that. This is like the 3rd or 4th time he's listed it.
 
I wonder how much over $200 the reserve is? I got one off ebay a while back for $200, might get another one for the right price. Oh, it was up for only 6 hours when I found it.
I'm going to machine a few of the tail housings to have on hand.
Jimbo
 
realsquash said:
Here's the bible of VSS stuff from Jags that Run:

http://www.jagsthatrun.com/Pages/SpeedSensors_Speedometer.html

I have used the 4 pulse model (4000 pulses per mile iirc) when I used a 7730 ECM on my 454 EFI and it worked great. On my Vortec swap I am not using a VSS at all. I am not sure of your application here, but the newer stuff used a much higher resolution (the 40 tooth one you are using) and if you are running a C3 or P4 ECM that isn't going to work. I had a hard time finding a 40-tooth replacement that would bolt onto the mechanical speedo cable output on the NP205 so I'm seeing how life is w/o it on the Vortec swap. I know it was a nice addition to the 7730 setup I had on the other truck.

Andy
Click to expand...

Thanks for the link Andy,some good info there.The adapter would be an easy solution for those who dont want to mess around with the housing.

I am going to be using the engine,trans,ECM and wiring harness from a 92 Diesel truck which only controls the 4l80E.I am in the learning stage of the wiring part right now but believe all I need now is a electronic speedo from a 90-91 Blazer/Sub.
 
I have that guy saved on my favorites on eBay. I've bid against him on some other stuff before. He must be loaded as he pays out of the ass for stuff he wants. Just interesting to watch him sometimes.

I remember bidding on one brand spanking new, NOS, D60 Spicer lockout hub with the yellow knob and this member jumped right in at the last few minutes and just skyrocketed the price up. I stopped bidding at $150 and this guy took it into the low $500 range and won the damn thing. $500 for ONE lockout hub!!!! :eek1: :eek1: :eek1:

I won a pair of those Rancho front triple shock hoops off him once. While the winning price was a little more than I wanted to pay, I figured at least I wouldn't have to look anymore for one. He listed another pair up a week later and they sold for half of what I paid for mine. Never saw another set after that, not even from any other sellers.
 
Wow! just found this thread! So glad I'm a member - this info rocks!

So dumb question, but on that 4L80E/205 combo - how is the speedometer/odometer driven?

Did the '91 Crewcabs have electric gauges and not mechanical?
 
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