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I got a 98 outback 5 speed, love the car. Only thing i dont like is that it runs  3k @70. Its obviously geared lower, ive heard of people changing gears in the diff. Anyone had any experience with this? if so was it worth it? just looking for some input, thanks.   - wheely

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You have to rebuild or replace the entire transmission and rear diff to re-gear it. Sure it can be done but the gains will be minimal. At most you could go from 4.11 to 3.90. Not worth the effort for 0.2 ratio change. RPM has virtually nothing to do with fuel economy. Keeping it in lean cruise with high manifold vacuum is the key to fuel economy. 3k rpm is no problem at all. These are high revving engines and they do well at high rpm. If you drop the rpm they have a shorter life with high loads and insufficient oil volume. 

GD

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  • 4 weeks later...
On 2/12/2019 at 6:57 PM, GeneralDisorder said:

You have to rebuild or replace the entire transmission and rear diff to re-gear it. Sure it can be done but the gains will be minimal. At most you could go from 4.11 to 3.90. Not worth the effort for 0.2 ratio change. RPM has virtually nothing to do with fuel economy. Keeping it in lean cruise with high manifold vacuum is the key to fuel economy. 3k rpm is no problem at all. These are high revving engines and they do well at high rpm. If you drop the rpm they have a shorter life with high loads and insufficient oil volume. 

GD

thanks for education! guess just has me weary taking it on the highway at high RPMs, no shakes or shutters just personal fear of hearing it die. 

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3 hours ago, wheely willy said:

thanks for education! guess just has me weary taking it on the highway at high RPMs, no shakes or shutters just personal fear of hearing it die. 

 3k on the freeway is not "high RPMS"  for this motor.  

It is made for it.  redline is 6500.  Cruising between 3k and 4k is not a big deal.

If you really wanted, this would be the way to do it.

Get a 3.9 trans and rear diff from a standard Legacy (non-outback) AND ALSO add the taller 5th gearset from a 04 Forester XT 5-spd (can be ordered from subaru)

That would drop the freeway RPMs signifigantly.........But then your 1st gear would be taller so not as good for hills and snow.

 

You could just add the tall 5th gearset to the 4.11 trans you have.  

But really, it's not needed.  These engines run just fine at 3k to 4k all day long.

Just make sure it's got a good timing belt set on it.

 

Edited by FerGloyale
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Just FYI. Stock size on the '96-'99 OB was the 205/70R15. The 215/60R16 is the same height, and was 1st used on the '98 Forester....if that's what you have.

If the 5-speed dies, you could put in a GT trans as it's the same 4.11 FD ratio, and is geared differently.....as is the '98 Forester. Unless I got it backwards?

OB: 

Model Range Trans. Code 1st 2nd 3rd 4th 5th 6th Rev. T.R. F.D.

 

US Legacy Outback MY97 TY752VACCA 3.545 2.111 1.448 1.088 0.871 N/A 3.416 1.000

4.111

 

GT:

US Legacy GT MY97 TY752VACBA 3.545 2.111 1.448 1.088 0.780 N/A 3.416 1.000 4.111

 

 

Found in the old Subaru Transmission Chart that was online.

Subaru Transmission Chart.pdf

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