Overdrive

[usadventureracing]

There maybe a thread already, but I was wondering if someone could tell me how to use the overdrive in my IIa. Thanks in advance

[superstator]

Push the lever forward, overdrive is engaged. Pull it back, disengaged. It has synchros, so use the clutch just as if you were shifting 3-4 or 4-3.

[usadventureracing]

Thanks do I need to be moving, can I push it forward when I am in gear and if so what gear do I start it in? Thanks

[KevinNY]

Use it only for cruising in Hi range 4th gear or 3rd on a big hill, it will last a lot longer that way. Check the oil level weekly.

[Jeff Aronson]

Actually, the Fairey overdrive can be used in any gear. Hwever, as Kevin has noted, it has limited uselfullness in the lower gears.

Starting in overdrive first will require a little more clutch slippage than you might want, so it's best to leave the overdrive disengaged until you reach third or fourth gear.

Shifting into overdrive when in third gear is good for entering a highway, because it allows you to accelerate to 55 mph before shifting into fourth. If your engine has any weakness in its compression, the lack of power will show up when you try to accelerate in fourth overdrive.

So I will often shift from third overdrive into fourth, while disengaging the overdrive. When I pick up speed again, I'll go into fourth overdrive.

Use the clutch when you engage/disengage the overdrive to save on the snchros. Kevin is correct in urging you to check the oil level dipstick on the overdrive regularly. It does not hold much. Also, there's a drainplug for the hypoid gear oil used in the overdrive. That drainplug is a unique thread pattern, almost impossible to find. If you remove yours to change the oil, which is a good idea as routine maintenance, make certain you tighten the bolt tightly. You might otherwise lose it and then the dry overdrive unit would fry its gears [don't ask me how I know[.

Also, there's a "neutral" position on the overdrive as with the transfer case lever, too.

Jeff

[superstator]

Mechanically it's just a second transmission between the main 4-speed and the transfer case - you can engage/disengage it anytime, just as you can shift from 1st to 2nd any time. I've often forgotten mine was engaged until I stopped at a light (or a couple lights), then shifted back out of it when stopped. Likewise you can start in any gear you've got the torque to turn, but it's generally considered rough treatment to use the overdrive outside 3rd or 4th. And like kevin said, keep a close eye on the oil - they don't hold a huge amount, and like to overheat and burn up their bearings.

[bobzinak]

lots of advice on how to shift your over drive..just a few observations i've had in using mine for the last ten years or so. recently the transmission was replaced with a rebuilt one from our hosts..ater getting all back together the over drive was very loud you coud hear the whine of the gears... It was not like that in the other transmission, so I knew that it hadn't changed. whay had changed was the fact that the bracket was touching on the keeper of the detent spring. not much but enough to transmit the tranny noises through the over drive lever. also the end of the od shifter bolt touched against the tranny case. a slight bending of the overdrive bracket moved the bracket an bolt away from the tanny case.. the overdrive is not much louder engaged than when it is just in fourth gear. so all you over drive owners out there in roverland, if your overdrive whines it could be that the bracket or overdrive lever bolt is touching your tranny case.. The fact that the overdrive lever was designed for a right hand drive rover puts the lever on the wrong side if the tranny..to fix this I took some round rod and bent it into a dog leg so that it comes up/crosses the tranny cover/and goes up on the opposite side. so you have the od shift lever on the left side of the trans tunnel. the nice thing about it is that you can shift both the transmission lever and the od lever at the same time. dont have to lean over, safer and easier.

[spechols]

The fact that the overdrive lever was designed for a right hand drive rover puts the lever on the wrong side if the tranny..to fix this I took some round rod and bent it into a dog leg so that it comes up/crosses the tranny cover/and goes up on the opposite side. so you have the od shift lever on the left side of the trans tunnel. the nice thing about it is that you can shift both the transmission lever and the od lever at the same time. dont have to lean over, safer and easier.
Photos please:)

[usadventureracing]

thanks for the comments, do I use gear oil and I was wondering what type of fluid I use for the clutch. Thanks

[Jim-ME]

Use only the brake fluid that our hosts sell or Castrol GT LMA in your clutch and brakes.
Jim