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opinions on ax15 or gears next?

Shimmy

Contributor
1977 Bronco
Joined
Jun 20, 2021
Messages
1,392
Loc.
Maple Valley
stock 302 with 3speed on the floor here. i'm running 35s with 3.50s. i've asked a few locals and get about equal suggestions in either direction.

what would you do next? ax15 swap or 4.56s? cost isn't a deciding factor for me. i figure i'll do both eventually but which swap would you prioritize and why? both axles and stock 3speed running fine and my bronco is a pavement pounder.
 

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Yeller

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Bronco Guru
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Mar 27, 2012
Messages
7,688
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Rogers County Oklahoma
I’d do gears first, it will be a huge improvement in the driving experience. If going to an ax15 may consider 4.88. Will be a little low for highway cruising comfortably with the 3 speed but will be perfect with the ax15. The ax15 and 4.56’s isn’t terrible, 4.88’s will be just right.
 

pfdff1115

Contributor
Bronco Builder
Joined
Sep 11, 2017
Messages
87
Loc.
Jamestown, IN
Both if your planning on sticking with a manual the ax15 is a good choice, but with that you'll want the gears to compensate for the bigger tires.
I swapped a zf in my bronco with 4.56 gears, the zf is more of a truck transmission not as nice as the ax15. however i can run 70 mph at 2600 rpm. i have 33" tires with 35" the rpm would be down even further.
 

ngsd

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Bronco Guru
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Messages
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I did the AX15 with 4.56 gears 35's on 18" Good choice
 

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DirtDonk

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Bronco Guru
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Nov 3, 2003
Messages
51,616
Absolutely gears first. But only the rear gears for the moment (and don't use 4wd until you know for sure you like it) so you can see the change even with the 3-speed and can then do the front.
Just leave the front driveshaft off until you do the front and then even if someone accidentally shifts into 4wd with the hubs locked, nothing bad will happen.

With the current gearing, if you change the transmission first you will gain a slight amount of giddyup off the line, but probably won't even be able to shift into overdrive so would mostly feel a lot of ho-hum for all the work you go through. Whereas if you do the gears first, you will benefit with both transmissions.
And the extra time spent driving it might find you changing tire sizes, which will possibly have you changing your gear priorities. It does happen...

So rear gear only, to save time and money up front, but mostly just to get it done with your options still open.

Paul
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
37,065
The new clutch you put in with the new transmission will be happier if the correct gears are already installed.
Gears first.
 
OP
OP
Shimmy

Shimmy

Contributor
1977 Bronco
Joined
Jun 20, 2021
Messages
1,392
Loc.
Maple Valley
Absolutely gears first. But only the rear gears for the moment (and don't use 4wd until you know for sure you like it) so you can see the change even with the 3-speed and can then do the front.
Just leave the front driveshaft off until you do the front and then even if someone accidentally shifts into 4wd with the hubs locked, nothing bad will happen.

With the current gearing, if you change the transmission first you will gain a slight amount of giddyup off the line, but probably won't even be able to shift into overdrive so would mostly feel a lot of ho-hum for all the work you go through. Whereas if you do the gears first, you will benefit with both transmissions.
And the extra time spent driving it might find you changing tire sizes, which will possibly have you changing your gear priorities. It does happen...

So rear gear only, to save time and money up front, but mostly just to get it done with your options still open.

Paul

thank you for spelling that out for me too! gears it is and likely going with a replacement drop in member and new axles.
 

lilthom

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Bronco Guru
Joined
Nov 29, 2005
Messages
1,714
What Yeller said, 4.88 gearing with the AX15 was a great match for mine on 35s.
 

sprdv1

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REBEL
Joined
Mar 8, 2007
Messages
81,996
I’d do gears first, it will be a huge improvement in the driving experience. If going to an ax15 may consider 4.88. Will be a little low for highway cruising comfortably with the 3 speed but will be perfect with the ax15. The ax15 and 4.56’s isn’t terrible, 4.88’s will be just right.


Agree as the others have said Post up when done
 
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