John Barrett
New Member
Hi guys want to get hold of a gkn overdrive. If anyone is thinking of selling .also would it work Ok on a v8 auto with a defender trasfer case .cheers.
jamesmartin
Well-Known Member
count the teeth on the input,as long as they are the same
John Barrett
New Member
Thankyou James for your reply do you mean the input from the overdrive and the same as what exactly cheers.
The GKN overdrive has a poor reputation for reliability - mainly due to the electronics. Also, it only works on 4th and 5th gears. I bought the Roverdrive, imported from Canada by Rocky Mountain Spares. A brilliant bit of kit - it's more than paid for itself in saved fuel in a year (18,000 miles). Cost £1400 and I paid a bit more for an oil cooler as I tow a lot. It also works on all the gears including reverse, just like the Fairey. Best upgrade I've ever done on the truck.
John Barrett
New Member
John Barrett
New Member
Thanks diapson I didn't know that they only worked on 4th and 5th .the reason I was going for one is that as I understand they will change better under load which would be the case with the auto the one you are talking about needs to be changed using the clutch. is this the case.I have read other good reports about them .cheers
You use the clutch to engage and disengage overdrive in the same way as any other gear change, but if OD is on you only need to change gear normally using the main gearstick. Not sure about using one with an automatic - you'd need to speak to the importer - Rocky Mountain Spares - about that. I think it only works with a manual box.
