Overdrive Unit, Installation Information

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  • 30,000 lbs Capability
Specifications Electronics


Installation Notes:
Installation is very simple in most applications as follows: Just remove the transmission extension housing and bolt on the Gear Vendors replacement housing which has an eight hole pattern to receive the overdrive. Tighten the eight nuts and take the driveshaft with the new yoke (included) to the local driveshaft shop to be shortened (as per the instructions). Plug in the electronics and fill the overdrive with the recommended lube, and you are ready to drive.



All trucks, RV’s, and vans, have clearance for the overdrive but some cars and streetrods can have very tight tunnel areas. Typically the overdrive fits these rides justperfectly but if they are tight it is usually just at the two upper rear case studs.These studs can be shortened easily and/or the tunnel can just get a 1/2 inch widedimple in that area. In tight applications you will attach the overdrive to the transmissionwith the Trans back up into position to determine exactly the point of contact. Themost that is ever required is this dimple (usually Then only if the subframe bracehappens to be in that area). As you can see above the overdrive is very compact (roughlythe dimensions of a standard coffee can) and looks very factory once installed. Kitscome with detailed installation instruction set.


Net Weight — 50-65lbs depending on application hardware.
Ratio - .78:1 or 1:1 (reciprocal 1:1.28)
Mechanically direct, hydraulically overdriven DeNormanville design.
Long life Epicyclic planetary.
Solenoid control valve 6-12 volt negative ground @ 2amps.
650-700psi relief valve shift circuit.
Low parasitic loss common vertex Raybestos clutch.
Gross Combined Weight Rating (recommended) 30,000lbs.
Pressurized lubrication circuit to planet pinion bearings, roller clutch,
input shaft pilot, planet thrust surfaces, and ring gear.
Pressurized 2-stage permanent filter circuit.
High speed Dual Row caged needle planet bearings.
Efficient Single stroke/rev plunger pump with non-return valve.
Fluid capacity 28oz/flat sump or 48oz/deep sump.
Fluid type — GM#1052271 petroleum based or GM#12346190 synthetic
18 Element single row roller clutch rated to 4500lbs spike torque.
Horsepower limitations — 1200+ call GEAR VENDORS for applications
above 1200hp.
Recommended service interval — change fluid every 10,000-15,000mi
depending on severity of duty.



Gear Vendors electronics offer several features unique to the industry. In thiselectronic age the importance of communication with the on board factory processorof any late model vehicle is a elect_large.jpgnecessity for good performance. Our systems allowmany specific features (depending on the vehicle), such as; automatic engagement,and disengagement (AUTODRIVE tm), auto lockout in 4wd mode, manual override, indicatinglights to show auto mode and engagement, double overdrive canceling (for vehicleswhere double overdrive would not be useful), automatic converter control during shiftsfor vehicles with lockup converters, accumulative shift counter to show you exactlyhow many times you used the overdrive over its life, troubleshooting indicating display,and digital ratio buffering to communicate with the vehicle computer.


These electronic features help you to get the most benefit every time you drive and allow for substantial performance improvements even when you just drive and let the AUTODRIVEtm circuit do the work.

Need information on individual overdrive application see the following list:

We have included a frequently ask questions section that may answer some of your questions, don't see answers you need, just give us a call we will be happy to review your application with you. The following links provide specific application information, performance data that you can expect and the price data for your specific vehicle.