Personally, I wouldn’t even entertain a GVOD purchase without the\u00a0Tailshaft<\/span>\u00a0Housing<\/strong>.\u00a0 This is probably the most crucial Gearvendor part of all the assembly.\u00a0 The overdrive unit itself isn’t that hard to find; actually, they are rather interchangeable with other makes and models of cars.\u00a0 The J-type unit I think was run in Volvos or some small car.\u00a0 So, when shopping for Gearvendor kits, the most important part to obtain is the tailshaft housing that fits your transmission.\u00a0 There are different Gearvendor tailshaft housings for the C6, or the E4OD tranny, or any other tranny.\u00a0 Also, there are different housings for 4×4’s.<\/p>\n The Tailshaft Housing is the blue item in this photo. It replaces the stock tailshaft housing on your transmission.<\/p><\/div>\n I think I remember Maximum Overdrive selling a new C6\u00a0tailshaft<\/span>\u00a0housing for several hundred bucks and Gearvendor selling theirs for over a grand. I can’t remember though, so don’t take my word for it. I read when i was looking for GVOD’s, that finding a used\u00a0tailshaft<\/span>\u00a0housing was as rare as hen’s teeth, since most junkyards don’t know the GVOD is a package deal (tailshaft<\/span>\u00a0housing\u00a0plus\u00a0<\/b><\/i>the unit). So they just trash the housing or leave it on the tranny, and I’m sure some sucker who buys the tranny will be extra confused on what the H happened to the end. Also, there is a heavy-duty metal cylinder that is used to splice the\u00a0tailshaft<\/span>\u00a0to the GVOD shaft. If the\u00a0tailshaft<\/span>\u00a0housing is missing, i doubt the cylinder is in the kit too since it was just held in by the compression of the\u00a0tailshaft<\/span>to the unit itself.<\/p>\n Driveshaft Yoke:<\/em><\/p>\n Try to find the GVOD yoke from the junkyard too.\u00a0 The Gearvendor unit has a different yoke than the standard stock Ford yoke.\u00a0 So, if you buy the Gearvendor and hope your driveshaft will fit in the end of the Gearvendor, it won’t.\u00a0 \u00a0It’s a GM yoke (i think 27 pin) and you’ll need to match up your u-joint sizes accordingly. I had to buy a 1330-1350 Spicer u-joint<\/a> conversion to make mine work. So if you can get that from the PO, you’ll save some trouble.<\/p>\n The yoke is the cylindrical shaft that affixes to the end of the driveshaft bearings. It is located at the end of the Gearvendor housing, on the far right of this image.<\/p><\/div>\n If you can get the driveshaft from the previous vehicle, this might solve your yoke situation.\u00a0 Also, if the driveshaft came from the same type of truck or van as yours, there is a small but probable likelihood that your driveshaft will swap out once you install the Gearvendor system on your tranny.\u00a0 Or if the PO’s driveshaft was longer, then you can take that driveshaft to a shop to have it cut and balanced to your length.\u00a0 So getting the old driveshaft is a prudent action.\u00a0 However, if the driveshaft is shorter than your wheel-to-gearvendor distance, then you are SOL.\u00a0 At least though, you got the right yoke and u-joint.<\/p>\n P- or J-Type Gearvendor Units:<\/em><\/p>\n Gearvendors come in a J- or P-type.\u00a0 The P-type is by far the most ideal for a large Ford truck or van.\u00a0 They are rated for more hauling.\u00a0 The J-type is set up for smaller applications, and the Gearvendor support guys try to encourage you to upgrade.\u00a0 Since buying a new gearvendor is expensive, you can make the J-type work.\u00a0 I’ve been running my J-type for 150,000 miles and no major issues except for a seal that went on me in the desert.\u00a0 The way to make a J-type function like a P-type, is to upgrade to a Gearvendor-brand deep sump, or if you really want to increase the potential, buy a Maximum Overdrive Brand deep sump and install that.\u00a0 I have a tutorial on that here<\/a>.<\/p>\n Seals and Shims:<\/em><\/p>\n You should call Gearvendor<\/a> if you buy it, and order a seal kit.\u00a0 Do the seals when you have the unit off.\u00a0 Also, buy shims from GV.\u00a0 I doubt your PO will rememeber to give them to you, especially if he doesn’t have\u00a0tailshaft<\/span>\u00a0housing.\u00a0 When you mate the Gearvendor with the tailshaft housing, the instructions tell you to insert some thin shims to absorb thrust while under load.\u00a0 They are about the size of a 50-cent piece, but much thinner.\u00a0 No junkyard in the world will think these are relevant to the sale of a Gearvendor used system, but it can’t hurt to ask for them if they still have the system installed on the vehicle.<\/p>\n Wiring and Controller:<\/em><\/p>\n Most think an Auxiliary Overdrive system is just an overdrive that connects to the tranny and driveshaft.\u00a0 But there is also many electrical components that need to be included.\u00a0 There is a controller that automates the activation of the overdrive at certain speeds and RPM’s.\u00a0 It also controls an auto shut off when in four wheel drive (if applicable) and it shuts down while in reverse (VERY BIG NO-NO driving in reverse with the GV OD engaged).\u00a0 Also, it has an “Manual\/Automatic” switch assembly.\u00a0 It is connected to the OD with what could be described as something like phone cord and connectors.\u00a0 Make sure the yard gets all that stuff for you as well.<\/p>\n Also, the Gearvendor setup has extensions for your speedohousing and speedocable.\u00a0 Make sure the yard picks up the speedocable splice, the speedocable in-line sensor, and the speedocable housing adapter.\u00a0 The section of speedocable extension is about 3-feet long and that must be included if you want the unit to know at what speed to shift into overdrive.<\/p>\n In summary, you should make sure the wiring contains all of the following:<\/p>\n NOTE:\u00a0 Even if the junkyard or PO does NOT have the electronics, that isn’t crucial.\u00a0 After running my OD for a year, the old controller finally burned up.\u00a0 I looked into hiring a local electronics shop to fix it up, but it was kind of expensive.\u00a0 In the end, I pulled all the Gearvendor electronics (now almost 30-years old!) and just installed a simple 12v switch to the solenoid.\u00a0 Whenever I want the OD engaged (like on the highway), I just flip on the switch.\u00a0 No controller needed.\u00a0 While it would be nice for guest drivers, I don’t really think it’s that big of a deal to flip off the OD when I slow down.\u00a0 It is a pain though when I’m in city traffic.\u00a0 (Also, I installed an NC relay connected to the rear backup lights circuit.\u00a0 This way, if the driver forgets to kill the OD and puts it in reverse, it will shut off the OD.\u00a0 NEVER RUN A GEARVENDOR IN REVERSE.\u00a0 Also, always wire up the solenoid with “key-on” power.\u00a0 If you leave the Gearvendor power on and turn off the vehicle, even with the tranny in Park, the vehicle will roll on a slope.\u00a0 VERY DANGEROUS.<\/p>\n So getting the controller is nice, and it allows you to forgo all these DIY considerations and risks.<\/p>\n The Gearvendor solenoid is located where the two thin red wires connect, in the image above.<\/p><\/div>\n Also, make sure you aren’t buying a 4×4 GVOD unless you have a 4×4, because that has different implications for the controller. Mine was a little off, so now i have a NC relay that I personally rigged up to shut off the controller and solenoid since my controller isn’t perfectly setup for my van.<\/p>\n Price:<\/em><\/p>\n How much are they asking for the unit and wiring? Just to compare, I purchased my GVOD for my C6 from a junkyard for $250 which came with the unit, all wiring, and\u00a0tailshaft<\/span>\u00a0housing. If he is asking for like $500 without a\u00a0tailshaft<\/span>\u00a0housing, I would pass on the offer. If you go to car-parts.com and search for Gearvendor, eventually, you’ll find a Type J or Type P for around $300. They are not ubiquitous, but I occasionally find them once a month just to compare prices.\u00a0 \u00a0Same goes for Craigslist and Ebay.\u00a0 They seem almost impossible to find, but that’s not always the case.<\/p>\n <\/p>\n Hope this helps.\u00a0 Post in the comments if you have any other suggestions on how to better shop for a used Gearvendor setup.<\/p>\n No warranty. You are responsible for your vehicle. For novelty use only. Not responsible for anything or anyone. Not responsible for damage to your vehicle, you, or anyone or anything.<\/b><\/p>\n Copyright 2000-2018\u00a0Nick Pisca<\/a>\u00a00001D LLC<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"![](\"http:\/\/www.nickpisca.com\/Alamo\/misc\/gv\/IMG_5664.jpg\")
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