I have an 85 Chevy K20 6.2 diesel, 4spd manual with a gear vendors O/D. It works great and i have never had any real issues with it other than the fact that whenever I go to shift out of O/D the gear vendors makes a loud banging noise that i can feel throughout the whole truck. I bought the GV brand new and it has done it all its life. I am very good about changing the oil on it too. Does any one know if this is normal? From what I have read nobody else experiences this with their Gear Vendors OD.
Gear Vendors loud banging noise
- Thread starter GilbeyK20
- Start date
teletech
Registered User
I'd heartily suggest a call to the folks at GV. I had a third-hand unit that was giving me trouble and they really did work to help me out.
How are you shifting out of overdrive, using clutch, lifting throttle pedal? I downshift the gear vendors without clutch and without lifting off the throttle, this makes for the smoothest downshifts.
Ask them how they use the clutch with an auto and yes improper shifting with or without a clutch will cause damage. What you need to accomplish with shifting is not any different then shifting an synchronized gear box. By leaving your foot on the pedal (use some common sense floored could lead to damage) is the engine trans and input side of the gear vendors raise in rpm while in the brief power by sprague only state of the gv unit. By allowing rpm's to raise the input speed will more closely match the rpm when the cone clutch engages. Pretty easier to match as the raise in rpm will be limited by the sprague. The clunk you are hearing is caused by the input speed being well below matched rpm and the cone clutch snapping the drivetrain up to speed. The gear vendors is not like an automatic in that a automatic can transition between two clutch packs, a gear vendors can only have one side of the cone clutch engaged at a time, and a cone clutch does not slip well it basically on or off. Pressure and slipping will effectively cause a cone clutch to tighten.
And my big worry for the morning, not the work related $10,000 warranty claim I have to file, not the fact my 6.9 is all tore apart waiting machinist's opinion on block, who is sick and a damn good friend, but did I get the powerflow of the sprague correct in the above post, for a stranger in Arizona. Thanks to google I believe I did. If you want to try at your own risk up shifting into overdrive can be made really smooth and clutchless with the proper timing if lifting off the accelerator and pressing the gv overdrive button. Want the shift to happen as driveline slack is just happening. On mine I press the button just as i am almost off the throttle.
