Ok got the overdrive in but more questions

spencnaz

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Got the overdrive in with a little machine work to make the u-bolts fit, everything is running smoothly.

The biggest question I now have is about the operation of the Gear Vendors unit. I have a toggle switch that is marked Autodrive and Manual. I understand what the Autodrive is, the computer handles that.
But at what speed does the GV kick in?

Also, I noticed a marked reduction in engine braking on the freeway, is this the overdrive operating?

When I pull away from a stop with Manual mode on and the switch activated, am I to assume that I'm in 1st over?

I can't seem to find operating instruction for this thing. All I know is that when I flipped the manual switch on or off when rolling, I could feel the overdrive klunk in or out.

I drove on the freeway and found that my speedometer is about 10mph fast, it was reading 55 but I was doing a little over 66 according to my stopwatch. If the rpms are to be believed from the stock tach (it's bouncing all over the place), it shows me pulling about 2200 rpm at 66 mph. I did the math and I should be seeing a little over 1800 rpms with in overdrive, not 2200 rpms. I'm wondering if the tach is waaaaay off too.

Is this result consistent with the overdrive operating?

I have 3.55 gears in the rear end. According to their chart, I should be at 2.76 when in overdrive.

I also should mention that I have 33" tall tires.

Sorry for the long post but I want to make sure this thing is working after all the hard effort I put into getting this thing installed.
 
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mankypro

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My GV is only active in 2nd gear and above and at 20mph and above. The clunk when shifting is normal - you should push the clutch in when you switch to OD.

My unit has a head unit with an on/off switch and lights that tell me when OD is available. You probably just have an older unit.
 

spencnaz

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My truck has the C6, so do I just back off the throttle and let the GV engage? I bought new lights for the thing last year and I don't get anything to light up. The lights have been in their box until today.
 

mankypro

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I can't help you with auto trannies. You know GV has unbelievable tech support - they're awesome. Just call on Monday and tell them you inherited the truck with it and ask away. I'm sure they can help and even email you a manual.
 

spencnaz

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Yeah I guess I'll have to do that, for the time being the truck is able to be driven on the freeway to work on Monday.
 
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