Hot Rods GV Overdrive-Underdrive (hands-on) Experience

I'm interested in hearing from members who run a Gear Vendors unit, specifically anyone who has done more maintenance than just changing the oil. So familiarity with parts sources, ***embly/dis***embly do's & don'ts, diagrams, etc. From what I've found Gear Vendors doesn't sell parts but offers a "service" to refresh their overdrives but it ends up being 1/3 the cost of a new unit (I'm not taking that path). They appear to be pretty simple units and common replacement parts needed are O-rings, solenoids and the clutches.

I'm working on a truck that has a GV behind a 904 and the overdrive is not shifting (only has roughly 24k miles on it but the truck isn't used often). I know this can be low or dirty oil, faulty solenoid, bad or dry O-rings on the solenoid shaft or, bad clutches. I'm looking at a kit through Maximum Overdrive and will probably go that way to refresh this unit. I'm just looking to hear from others who have messed with these on their own.

 

@squirrel , have you had any experience with GV?

 

I've never overhauled one. We either installed new units or replaced warranty units. Mostly in motorhomes.
Usually the motorhome owner would call on their way to Alaska saying they had an issue. They could drive in direct and still keep moving without a tow bill. We would then contact Gear Vendor and they would ship the replacement unit. This way the traveler wouldn't be inconvenienced any longer than needed. After the job was completed we would return the core to Gear Vendor.
What I learned, though, is that most operators did NOT turn off the overdrive when coming into cities and the unit needlessly "hunted" between drive and overdrive. The other issue was not turning off the overdrive when slowing down .The unit should not be used when coasting down hill or letting off the gas....endeavoring to engine brake. There really isn't a lot of fluid in these things...even with the bigger capacity sump. I always thought they might hold up better if there was a larger reservoir and some sort of way to cool the fluid.
Sending your unit back to Gear Vendor isn't such a bad idea.

 

Have you contacted GV for input on the issue? They were real helpful for my dad who had one in a Motorhome. I don’t recall the issue he had, but they pretty much told him what was needed to correct it.

 

I've driven with them quite a bit, but never been inside one.

 

Here's some info that might be useful:
https://www.dieseltruckresource.com...l-topics-93/repairing-my-gear-vendors-322155/

 

I read they got their start when AMC went under and he bought loads of the old Lay**** OD

 

This was my brother's truck so I have little knowledge of what he did to resolve this with Gear Vendors but I do know he was having issues and did speak with them. I may call them myself as a follow up.

Thank you Phil for the link. I'll read through that post to see what more I can learn.