Q's on rear axle swap - Third Generation F-Body Message Boards

Jeep · 09-10-2009, 07:49 PM

I have 2 '89 Formulas. 1 of them is a 5-speed, the other is automatic. Both are 305 TBI cars.
I'm starting to hear a fair amount of rear end roaring in the auto car.
I thought I'd swap the rear axle assembly from the standard shift car into the auto.Do any of you folks know of any problems there may be, or is it a direct swap out?

Also, what ratios were available in these 2 cars?

Thanks,

Jeep

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//<86TA>\\ · 09-10-2009, 08:10 PM

is will be a direct swap only difference would be if one has disc brakes and the other has drums.

as for ratios, on the homepage, on the right of the screen is a section for firebird tech data, under 89 you will find the options for ratios

Jeep · 09-10-2009, 08:40 PM

Quote:

Originally Posted by //<86TA>\\

is will be a direct swap only difference would be if one has disc brakes and the other has drums.

as for ratios, on the homepage, on the right of the screen is a section for firebird tech data, under 89 you will find the options for ratios

Thanks TA,
both are drum brks, but now I'm a little bummed out. Looks like the standard trans car has lower gears which will add about 300 rpm or so @ 70 mph.

Thanks again,

Jeep

//<86TA>\\ · 09-10-2009, 08:52 PM

Quote:

Originally Posted by Jeep

Thanks TA,
both are drum brks, but now I'm a little bummed out. Looks like the standard trans car has lower gears which will add about 300 rpm or so @ 70 mph.

Thanks again,

Jeep

thats not much really, unless you are looking to squeeze every MPG you can out of the car.

Jeep · 09-10-2009, 09:12 PM

Quote:

Originally Posted by //<86TA>\\

thats not much really, unless you are looking to squeeze every MPG you can out of the car.

I know it's not much and most folks wouldn't give it a second thought, but I'm a mechanic by trade, and I've always liked for my engines to turn low rpms.
The slower they can turn and not get bogged, the longer they last.

Jeep

big gear head · 09-10-2009, 09:24 PM

Fix the rear end that's in it now. It's probably just a bad bearing.

Jeep · 09-10-2009, 10:13 PM

I plan on totally rebuilding it, but right now, it's my only transportation. I can swap the assembly in half a day or less, rebuilding will cost alot more than I can afford right now, and I may run into needing parts that aren't available in this small town.

big gear head · 09-11-2009, 08:01 AM

If it's just a temporary swap then why sweat it? Just swap it until you get the other one rebuilt. If you need parts let me know.