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VSS options

Jumppr

Jumppr

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I had originally planned to get my NP205 output cover modified for the sensor plug and tone ring by ORD. I started looking around and found a couple other options.
Some people say you don’t need it on the transfer case as long as there’s one on the transmission.
A company called Behemoth Drivetrain offers the mod as well as another option to add the tone ring and sensor to the yoke.
Does anyone here have any opinions?

I’m planning to run a 5.3LS and 4L80 transmission.
 
I used the ORD setup. Needed it for my '90 TBI Blazer. Works fine, I was rebuilding the 205 anyway so went with the tone ring and sensor.
 
If you mount it on the transmission it will not act right when you put the truck in low range. Speedometer will be way off and the transmission shift points will be funky in low range. This is because a sensor on the trans does not take into account the gear reduction of the t-case. If you have a 2:1 low range (like a NP205 for example) a trans mounted sensor will think the truck is going twice as fast as it actually it. A buddy did a 5.3/4L60E swap a few years ago and I tried to tell him this but he insisted on installing the sensor on the trans. After fighting with it for weeks he finally gave in and mounted the sensor on the t-case output which solved his problems. Keep in mind that that the factory Chevy setup has the speed sensor on the t-case output for this reason also.
 
Thanks! Has anyone used the pulse generator that doesn’t require the tail shaft mod? A friend of mine is a Dakota dealer and he swears by em.
 
I don't think a pulse generator is a terrible idea. GM used them on some applications stock (some late 80's cars IIRC) so as long as it's well crafted, and has the output you need, why not?

I want to say that some of the GM applications later on got away with the t-case mounted setup by using a VSS on the output of the transmission, and using a switch to tell the PCM the vehicle is in 4WD. The t-case being a fixed ratio, it would be easy to code into the PCM.
 
dyeager535 said:
I don't think a pulse generator is a terrible idea. GM used them on some applications stock (some late 80's cars IIRC) so as long as it's well crafted, and has the output you need, why not?

I want to say that some of the GM applications later on got away with the t-case mounted setup by using a VSS on the output of the transmission, and using a switch to tell the PCM the vehicle is in 4WD. The t-case being a fixed ratio, it would be easy to code into the PCM.
Click to expand...

I'm not 100% about GM applications with the speed sensor on the trans as I have never seen one, but doesn't mean they don't exist. The 241 transfer cases which were very common starting in the late-80's all had VSS on the transfer case output that I know of. But as you said you could code in the difference through the PCM assuming you had a signal showing transfer case gear position and the ECM was equipped with an area of data tables it could revert to. Regarding the friend I mentioned above I know he did have to get an ECM that had this available (ability to sense 4 low). While it doesn't correct the speed input for 4 low it does change the trans shift points some....but again, it still relied on the an accurate speed signal as it didn't allow him to change the change or calibrate the speed reading because it was in 4 low. The first ECM he got must of been out of a 2wd and didn't allow him to access or make active the 4 low data tables with HP Tuners, so he had to go to the junkyard and buy another ECM from a 4wd truck. Just to clarify, I'm not a tuning expert by any means.
 
There is a VSS sensor on the 4L80. And I’m also running a doubler so programming the 4lo numbers would be way too much work I think. After doing a little more research I think I’m just gonna get the tail shaft mod done.
 
Hmm....I’ll check into it. I’ve never heard of them before this week. I emailed a question and the dude called me back the same day to explain their products.

Was the other thread on Pirate or what?
 
Wow! I just read some reviews on his Facebook page. He’s either the worst person to deal with or the best. There is no in between. Maybe since it’s just a small part I’m getting it won’t take forever line the other horror stories I’ve read.
 
6.2Blazer said:
I'm not 100% about GM applications with the speed sensor on the trans as I have never seen one, but doesn't mean they don't exist. The 241 transfer cases which were very common starting in the late-80's all had VSS on the transfer case output that I know of.
Click to expand...

Novak covers the two sensors under "speed sensing": https://www.novak-adapt.com/knowledge/transmissions/automatic/4l80e/

Slight correction, 90-91 R/V's used a 241 with VSS, 1989 241, and all 208's were cable drive speedometers.

For educational purposes. :)
 
Hope I’m not too late. Someone already said Behemoth is a crook. I had to go through the process of getting my money back because they’re no longer in business. Go with ORD!
 
Stay far far away from Behemoth Drivetrain. My friend almost got screwed by them. He eventually got his money back. But he lost lots of wasted time and aggravation with his project. I warned him too....
 
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