253 Diff

**GNW1974** · 03-07-2013, 02:59 PM

Jut wondering the concensus out there on this, I would think a 3:36 would be better for a 253 running an M20 box, due to the better first gear ratio, 3:08 if you are running the M21 and want top speed. My Ute is running M20/3:08 combination and 1st gear is pretty sluggish and I would like to change to a 3:36, I am not interested in top end as it will be a weekend cruiser only and it is the original specification. One web site lists the 3:36 diff as the performance option for the 253/M20 combination. (M20 has 3.05;1 ratio 1st gear compared to 2.54:1 in the M21)

**HK1837** · 03-07-2013, 05:11 PM

308 and aussie M21 was always standard with 3.36. 3.55 was performance option and 3.08 was economy option.

In HQ and HJ, 253 and M20 was standard with 3.08, performance option was 3.36 (or possibly 3.55).

HX and HZ 253's were dogs so they made the 3.55 the standard dif with 253 and M15 or M20 to make them feel faster. Economy diff was 3.08 except on tonner where 3.36 ws the economy option. 3.36 was standard with HX-Z 253 if M21 was optioned (passenger only).

Which one you use comes down to tyre size and what you want it for. If it was simply for a weekend cruise car I'd even consider an M22 behind a 253 or 308 with a 2.78:1 diff to give it OK highway capability and still be OK in first. Standard-ish 253 M20 in a ute would be fine with a 3.08, just no good for reversing up driveways.

**Innuendo** · 03-07-2013, 05:27 PM

It's really quite simple. If it's a dog off the mark with what you have as far as diff ratio and tyre size change the diff ratio to something that improves the result.
Quicker take off will also mean higher RPM at highway speed. I.E: 100Klms at 2,100 RPM vs say 100Klms vs 2,400 RPM
As you stated you don't care about top end speed, but you should take into consideration highway RPM and fuel economy. If you just buzzing about town on the pose then 3.55:1 would be fine.

**Vombil** · 03-07-2013, 06:47 PM

Originally Posted by Innuendo

It's really quite simple. If it's a dog off the mark with what you have as far as diff ratio and tyre size change the diff ratio to something that improves the result.
Quicker take off will also mean higher RPM at highway speed. I.E: 100Klms at 2,100 RPM vs say 100Klms vs 2,400 RPM
As you stated you don't care about top end speed, but you should take into consideration highway RPM and fuel economy. If you just buzzing about town on the pose then 3.55:1 would be fine.

im on the pose around town with 308 3.55 and supra 5er. gorgeous set up

**buck** · 03-07-2013, 07:04 PM

I dont find the 253 m20 & 3.08 sluggish in first or reversing up our steep drive way. I have driven most of the setups mentioned including the supra 5 speed with 3:08, but the worst was my hz 253 m15 with a 3:55 couldn't even get from melbourne to glenrowan with out filling up. As others have said 4 barrel carb extrators and a nice tow cam make the m20 & 3:08 a good allrounder

**wbute** · 03-07-2013, 07:36 PM

Blue 253 with M20and 3:08 will smoke a blue 253 with M20 and 3:36. The reason is you can hold it longer between gear changes. There is bugger all difference in take off pick up. I would not use a M21 with a 253 unless you like slipping clutches.
However if you have steep tight driveways 3:36 probably won't be low enough.
But to be honest, the best diff is the one you don't have to pay money for. And at the end of the day most new cars are quicker than a 253 around town these days anyway.

**wbute** · 03-07-2013, 07:37 PM

Blue 253 with M20and 3:08 will smoke a blue 253 with M20 and 3:36. The reason is you can hold it longer between gear changes. There is bugger all difference in take off pick up. I would not use a M21 with a 253 unless you like slipping clutches.
However if you have steep tight driveways 3:36 probably won't be low enough.
But to be honest, the best diff is the one you don't have to pay money for. And at the end of the day most new cars are quicker than a 253 around town these days anyway.