Gear Vendor OD troubleshooting

ocnorb

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So I let the wife drive the IDI to work one day and now the OD won't work.:dunno:backoff LOL

I seldom use the truck in the summer- I commute on my bike unless there is ice or lightning until diesel is under $1.99 again.:rolleyes: :rotflmao

It started when she was decelerating getting off the freeway. She says it started to shudder horribly. When I test drove it she was right! It sounded like the rear end was goin to come out!!

During the test drive it would shift in and out of overdrive manually just fine, but if you let the auto-box shift it had problems. As of yesterday it will no longer shift into overdrive at all. :eek:

I'm not sure where to start. I don't even know where the fluid goes in the dang thing! It may be low. I can see the drain plug, but no fill level plug to check. Anybody with a GVO have any advice??

I searched the net and found little on maintaining these units. :yell:
 

RLDSL

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I'm not sure how the GV units fill I worked on the volvo units and they filled through the main box with a common fluid, but what you are describing sounds like it was engaged while in decel in too low a gear which is a major no no for a laycock OD unit. She may have fried the thing. What you are describing is a common failure mode.
I may still be able to get you rebuild parts for those things. I'd have to check and see if the guy is still selling them. Let me know if you want me to find out. They are fairly easy to go through and the parts are pretty reasonable if you don't get them from GV.
 

87crewdually

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First ting is check fluid level through the fill plug on the right side of the unit near the tail shaft. IIRC it's a 11/16" or 3/4" wrench 12 point bolt. The other bolt you see at the bottom (9/16" wrench) is a pressure test port, not a drain. Top the fluid level after noting high low it is. Use a piece of wire as a dipstick to see the level.
Respond back with your results and we'll go from there as it could be other things but you gotta start with the basics.
 

Agnem

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You do have the electronics box with the speed sensor connected correct? Some people have circumvented this protective device and just rely on their ability to remember to kick it out of OD when below 17 MPH or so. If you don't have this box, and your wife forgot to kick it out, then exactly what I would expect to happen, happened.

If you do have the full electrical hookup, then connect a test lead to the solenoid on the GV unit under the truck, and see if it is getting a signal to engage. Might be a little tough. I would take the tires off and run it in the driveway with a chain attached to a tree. Coming off the jackstands at 40 MPH with you under there would not be pretty.
 

icanfixall

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As posted above.. These are really simple units. They have an cam excentric that runs a hydralic piston that pumps up pressure to engage the system. Sometimes the friction material will start to flake off and plug up the suction screen. To clean that you drop the bottom fluid sump but. Do the easy stuff first like posted above. Hopefully its not worn out. If it is its easy to fix. Just don't try using it till its fixed. You still have a good trans in front of this gv and running the stock trans gearing wont hurt the gv any because its not engaged. Thats the best part of gv. If they break on the road you countinue on your way without it. The US Gear over under units break on the road and you are stopped right there....:D
 

ocnorb

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You do have the electronics box with the speed sensor connected correct?

Yes. It is all there. The controller worked quite well prior to this.

The previous owner put a 4.10 speedo gear in it; it actually has 3.55's. Would this be problematic? (Other than the speedo is way off at anything over 30mph):dunno

I will try the simple stuff tonight and report back. The truck still drives fine as is, just no OD.
 

WrickM

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Yes. It is all there. The controller worked quite well prior to this.

The previous owner put a 4.10 speedo gear in it; it actually has 3.55's. Would this be problematic? (Other than the speedo is way off at anything over 30mph):dunno

I will try the simple stuff tonight and report back. The truck still drives fine as is, just no OD.

That speedo gear is under $10 at any chevy dealer. i have the part number around here somewhere's. It will make the GV a little easier to use since it is shifting based off of speed. I don't think it's your issue, just sayin.
 

crashnzuk

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A 4.10 speedo gear will make the GV think you are going faster than you actually are. This will let it engage at too low of actual road speed (driveshaft rpm). You need a certain driveshaft rpm to create enough internal hyd pressure for the unit to work correctly. With 4.10s, you can engage it at a lower speed because the driveshaft rpm is higher at a given speed than a 3.54 equipped truck. Gear ratio and tire diameter need to be factored in when setting up the default speed.
Travis..
 

RLDSL

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With that speedo gear faking the thing out all this time keeping it engaged at too low rpms, I'm afraid the thing has most likely bit it. That would be the same as manually engaging it too low and leaving it in too long for the entire time youve had it. Seriously not good
 

ocnorb

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Great advice here...

That speedo gear is under $10 at any chevy dealer. i have the part number around here somewhere's. It will make the GV a little easier to use since it is shifting based off of speed. I don't think it's your issue, just sayin.

If you have the part number that would be great! :thumbsup:

I'd really like to get it set up right now that you guys have explained that it might be toast.LOL

I was called into work on an emergency last night, so I couldn't spend any time on the truck. Tonight!
 

crashnzuk

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See if you can find an install manual for the GV, maybe on their site? I think it tells you how many driveshaft revolutions you need before there is enough hyd pressure to run the unit. You need to figure out what that equates to in road speed with your gear/tire combo and use that speed as the threshold for the unit being able to turn on.
Travis..

EDIT; I also was thinking about this last night before I fell asleep. You speedo would read slow with the 4.10 speed gear and 3.54 diff. Meaning you would have more road speed than is indicated on the speedometer, so you might have been ok depending on what the box was set to. But, you need to get your speedo right and make sure you have the correct engage speed calculated so you know it is right.
 

ocnorb

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See if you can find an install manual for the GV, maybe on their site?

No luck with anything online from them. I called them about a parts breakdown and was told "We do NOT sell any internal parts, but for $950 we will exchange your unit and give you a new one year warranty."

A speedo gear is $60 from GVO.

The guy at GVO I talked to didn't think that the speedo gear was the problem. He said it was a classic case of worn clutches.

Being that I don't have $950 to drop on it right now, I may tear into it and visit my local transmission shop to see if they can ID or source the clutches for me. I have had a local re-line shop custom build a clutch for my Willys. Maybe they can re-line these too?



Is it just me or does it suck when a company won't sell parts???-cuss
 

SparkandFire

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How lovely, "we wont sell you any parts"

Gotta love customer service these days. i've heard that before, GV won't so much as sell you any part of their unit... Im surprised they don't seal the cases or something along those lines. Others have tried to get a hold of a different adapter plate, but GV tells them to F*CK off...
:mad:
 

87crewdually

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No luck with anything online from them. I called them about a parts breakdown and was told "We do NOT sell any internal parts, but for $950 we will exchange your unit and give you a new one year warranty."

A speedo gear is $60 from GVO.

The guy at GVO I talked to didn't think that the speedo gear was the problem. He said it was a classic case of worn clutches.

Being that I don't have $950 to drop on it right now, I may tear into it and visit my local transmission shop to see if they can ID or source the clutches for me. I have had a local re-line shop custom build a clutch for my Willys. Maybe they can re-line these too?



Is it just me or does it suck when a company won't sell parts???-cuss

I have all the knowledge to help you but I need you to do the simple things first. CHECK The OIL LEVEL. If that's fine then we can do some simple tests. You could have a blocked orifice or sticking solinoid valve or torn o-ring or worn pump or smoked clutch ect ...
One step at a time. I just rebuilt mine a few months ago getting the conical clutch and re-seal kit all through gear-vendors, so relax. Can't help you though if you can't perform simple tasks like checking level.
Worse case scenario this the conical clutch for around $200.
You must be registered for see images attach


This is the unit "gutted" ready for rebuild. Just a bunch of valves, a piston pump, cone clutch, planetary with a one way clutch and a case. Not much to it. These things been around longer tha G/V so don't worry about parts until you know what's wrong.
You must be registered for see images attach


Again check fluid level and the connections on the solinoid on the driver side of the unit. The speedo gear is irrelevent to it working or not.
Here's a link for speedo gears though. http://www.transmissioncenter.net/speedometer_calibration_______va.htm
 

ocnorb

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I just rebuilt mine a few months ago getting the conical clutch and re-seal kit all through gear-vendors, so relax.

I am relaxed... I apologize if that post came off more "rant" than I intended.cookoo

I can check the fluid... just need time when the sun is up!!LOL

How do you get parts from GVO? Are you hooked up with a dealer/distributor?

I only ask because they made it real clear that they don't sell parts. Not generally what a guy wants to hear.

Glad to see that it is possible to rebuild! Thanks for the link!:thumbsup:
 

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