1984 5th Avenue differential swap.

[Rustyroger]

My 1984 5th Avenue has a tall axle ratio, 2.8 or possibly 2.6? Presumably what it left the factory with. Advancing years means I no longer relish the thought of pitching a tent when I go to car show weekends, and I have a small caravan (travel home?) about 1500lbs in weight I want to use instead. I think its too highly geared to cope with it for sustained 50-60 mph travelling. How easy is it to swap out the differential? Would it be simpler to just swap the whole axle, and what ratio would be more suitable?
TIA, Roger.

 

[Duke5A]

It's worse. That thing is 2.24:1.

In the UK? That's going to be rough. Not many parts cars to be found over there. The easiest way is to find a 8.25" out of a fleet car with a 4bbl. It'll have 2.94 gears and bolt right in. Just have to shorten the driveshaft. There are no aftermarket gear sets available for the 7.25" you have now.

Next best bet is retrofit. Some people here have used Mustang 8.8 axles. That'll be something like a 3.2:1. Don't know what it entails though.

 

[Mikes5thAve]

It would be simpler to swap out the whole axle, if you can get one where you are, and actually preferred because the 7.25 you probably have now isn't known for its strength. You wouldn't want to put a lot of time and money into the gear change only to have it grenade.

Does your axle have a squared off cover with axle tubes that narrow right before going into the housing or is it more round with consistent diameter tubes? Or post a pic. Maybe export got better axle to begin with.