cooked overdrive

[mark4130]

hey guys,

just bought a 79 2 door rangie with a p76 4.4l with an overdrive fitted.LT95
turns out the overdrive unit has been cooked and is a bit noisey.(sounds like the gears are getting chewed up)
is it possible to remove this unit and change the gear ratio in the transfer case?
i would like to run 33/35s at a later point,would this give me a better ratio for the highway instead of changing the transfer gears?
or should i just rebuild the overdrive?

mark

[Philip A]

The Fairey overdrives are now very difficult to get parts for so if it has a chipped gear you are stuffed.
However the more common problem is that the needle bearings between the inner and outer shaft fail and the outer races are machined into the gear sets and these get marked (brinneled).
You can get bearings which have an outer race integral in the correct size.I still have one at home! The major bearings are the same as in the LT95 box so are easy tio get
The thrust washer also dies and this must be remade as I do not think you can get em. They are quite simple to work on.

SO whether to rebuild depends on whether the gears are OK.

If you are going to fit 35s then the stock gearing is probably fine with a 12% increase from the tyre diameter. All you should do is get a drop gear and plate and refit.
regards Philip A

[lucy]

If you are going to fit 35s then the stock gearing is probably fine with a 12% increase from the tyre diameter. All you should do is get a drop gear and plate and refit.
regards Philip A

I thought going from a Range Rover standard tyre diameter of 29" to 35" was a 21% increase, and gearing changes would be mandatory?

[Philip A]

With a 4.4 and 35s I think the stock gearing without a fairy would be fine on the highway.
I do not think 35s are 21%. My 12% was wrong but my calculator makes it 18.5%. the Fairey is something like 21%, so the gearing will be about the same in top as with the Fairey and standard tyres.
regards Philip A

[mark4130]

hmmm guess i'll remove and inspect.
the idea of running 35s and stock gearing sounds the go though,ive read the overdrives dont like to much touque and its common for them to overheat.
thanks Philip A

mark

[cloughy]

With a 4.4 and 35s I think the stock gearing without a fairy would be fine on the highway.
I do not think 35s are 21%. My 12% was wrong but my calculator makes it 18.5%. the Fairey is something like 21%, so the gearing will be about the same in top as with the Fairey and standard tyres.
regards Philip A

I doubt it

[Philip A]

Remember its a 4.4 with lots more torque than a 3.5.
Regard Philip A

[cloughy]

Remember its a 4.4 with lots more torque than a 3.5.
Regard Philip A

Yea but i've had 4.4's with big tyres, it'll do it but won't be happy, personally i'd just turf the fairy

[mark4130]

just removed the unit and having troubles with the second serclip so cant check the gears yet,but have removed a chewed up bearing case and a few ballbearings.Ill need to buy a larger set of serclip pliers tommora to check the rest.
Cloughy do you recken the high gear in the transfer case should be changed then maybe?

mark

[Rangie ute on 38'']

sounds like for what your going to spend fixing, just buy a good runner and keep that one for a spare

[Philip A]

Remember its a 4.4 with lots more torque than a 3.5.
Regard Philip A

Yea but i've had 4.4's with big tyres, it'll do it but won't be happy, personally i'd just turf the fairy

I AGREE WITH YOU. Thats what I was saying. Ditch the Fairey and just go with the normal gearing. Sorry if I wasn't clear.
Regard s Philip A

[cloughy]

Remember its a 4.4 with lots more torque than a 3.5.
Regard Philip A

Yea but i've had 4.4's with big tyres, it'll do it but won't be happy, personally i'd just turf the fairy

I AGREE WITH YOU. Thats what I was saying. Ditch the Fairey and just go with the normal gearing. Sorry if I wasn't clear.
Regard s Philip A

Ahhhh, i see, yea yea same fing i fink

[cloughy]

just removed the unit and having troubles with the second serclip so cant check the gears yet,but have removed a chewed up bearing case and a few ballbearings.Ill need to buy a larger set of serclip pliers tommora to check the rest.
Cloughy do you recken the high gear in the transfer case should be changed then maybe?

mark

Depends what high range is fitted already, just put the tyres on and see, you can always change later, transfer gears can be done in the vehicle easy enough, 33's will be no worries 35's may stretch its legs a little, depends on how well tuned/condition/cam etc the 4.4 is