SF 1.447 low range in SH XT?

BriefObsessions

Forum Member
Joined
Jun 15, 2020
Messages
28
Location
Australia
Car Year
2016
Car Model
SJ Forester XT
Transmission
CVT
Hi all,
Quick question, will a 1.447 low range set go into a SH XT 5MT case? Can the 1-5 turbo gears be retained? I sent an inquiry off to All Drive about building me one using their 1.6 low range but they said they had a setback and are being re-engineered. Still another 6 weeks away at least.
 
You will need to use a SH NA 5MT Transmission, and swap the 1.447 Low Range gear set into it. The XT 5MT does not have a low range at all. You likely could also use a SG NA 5MT case, as I believe the only difference is the SG ones have a speed sensor, whereas the SH has the speed sensor elsewhere
 
Thanks, I realize the XT doesn't have a low range, I was was just wondering if the cases are the same between single and dual range gearboxes. I'm hearing I would need to find an SF box for the low range and an SH (or SG) box to put everything in. Can I use the XT 1-5 gear set?
 
The low range is part of the input shaft on na models. (Input gear set on low range boxes is split in 2 parts (Right image) while it's one long shaft in single range gearbox(Left image)) So if fitting a low range you will need to use the low range gearbox case and gear shafts. It is possible to swap the 5th ratio (far left in images) between the gear sets. No idea about the other gears. I assume you are planning fitting your XT 4.44 ratio into your dual range gearbox too?
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Ah thanks for the pics, I can see the difference between the cases now. I knew how the low range worked, just didn't know how interchangeable the cases were. Yes I am planning on sticking with 4.44, I realize the crown wheel may need to be trimmed down. Think I'll wait for a bit longer for ADS to get their 1.6 finished, although it seems like it's been coming for years so maybe I'll try and get my own made up. I wonder if a 16 & 23 ratio could be used on both sides of the low range gears, which would give a 2:1 ratio...
 
SF boxes have weak synchromesh compared with SG boxes, particularly SG series II, IIRC.

All gearboxes are torque multipliers of some description. If you multiply the torque too much, something, somewhere will break :(.
 
Ratbag said:
SF boxes have weak synchromesh compared with SG boxes, particularly SG series II, IIRC.
Click to expand...

That's correct, as well as reverse gear and fifth gear off memory.

The best box is a SH Dual Range Box, with the SF Low range. Some people have had success modifying the box and fitting the low range out of a L Series.

Alternatively, All Drive Subaroo can build the entire box with the best components ready to go. It can get expensive though, a friend of mine has one of their built DR boxes in his SG XT, and it's RRP is $17K
 
$17K?!!! Wow. I knew it would be expensive, but I was only thinking around 5K :ROFLMAO:

Think I'll have a go at putting one together myself at that rate.
 
BriefObsessions said:
I wonder if a 16 & 23 ratio could be used on both sides of the low range gears, which would give a 2:1 ratio...
Click to expand...

I used 19 & 25 ratio on both sides which gives 1.73 and can confirm that fits. 19/25 at the front gives very little room from the diff and gearbox housing so I do not think 16/23 would fit but I'm not going to say that it won't as haven't tried. There is a bit more room in the rear. 19/25 front and 16/23 rear would fit and give 1.89 ratio low range.

Gearbox.PNG
I did it the dodgy way and hacked and refitted the 19 & 25 gears which meant that when you spin them around the helix angle faces the wrong way. This causes the axial forces to be going the wrong way and makes the shaft want to move. So you'd obviously want to cut new gears to get the helix angle the right way around.
Low range.PNG
 
That is awesome, was wondering if anyone had a custom setup. Gives me something else to think about. Are you running it in your car?
 
No the secondary shaft moved and self destructed when I was testing how strong it was. Was awesome for a short period of time. I'd like a second go at doing it properly, but haven't got around to doing anything yet.
 
I think that sooner or later, someone will come in with something like a 2:1 low range gear set....
 
BriefObsessions said:
$17K?!!! Wow. I knew it would be expensive, but I was only thinking around 5K :ROFLMAO:
Click to expand...

They probably do them around that price too, his box has literally everything done to it, essentially, the whole internals are brand new, and shot peened, included Cusco diffs, etc
 
if i may ask what kind of gearboxes then outbacks uses , those dual range models that 2nd gen has and 3rd gen as well. ? are they same gearboxes as foresters or separate ones ?
 
They have the same housings, the main differences would be the differential final ratio and the low range ratio.
 
The Outbacks like your old one are interchangeable with first gen Foresters (same external stub axles on the gearbox), but different ratios. I don't know about your newer Outback. The SG onwards Foresters have the axles stubs go into the gearbox, which is different to first gen Forester and Outback. My mate swapped an SF gearbox into his early 2000's Outback to get the lower low range and was a straight easy swap.
 
Red XS said:
I used 19 & 25 ratio on both sides which gives 1.73 and can confirm that fits. 19/25 at the front gives very little room from the diff and gearbox housing so I do not think 16/23 would fit but I'm not going to say that it won't as haven't tried. There is a bit more room in the rear. 19/25 front and 16/23 rear would fit and give 1.89 ratio low range.

View attachment 4160
I did it the dodgy way and hacked and refitted the 19 & 25 gears which meant that when you spin them around the helix angle faces the wrong way. This causes the axial forces to be going the wrong way and makes the shaft want to move. So you'd obviously want to cut new gears to get the helix angle the right way around.
View attachment 4161
Click to expand...


I'd like to hear more about this if you don't mind sharing? First time I have come across anyone mucking around with the low range gears in this way, really cool! I have 2 spare L series gearboxes, one which is pretty much parts only, another which is unknown but apparently good. Have absolutely no reservations about trying something like that. I was planning to try the cut n shut 4.44 pinion shaft trick in my L box, still might if i ever get around to it, but this seems more DIY friendly for a better result.
 
jf1sf5 said:
I think that sooner or later, someone will come in with something like a 2:1 low range gear set....
Click to expand...

And watch the gearboxes return with first gear blown to bits!

The low range needs to be moved to the back of the drive gears between these and the centre diff. This would require another housing that would effectively extend the length of the box. That would have a flow on effect with other components. Plus no one knows what would happen if the pinion shaft is constantly spinning at significantly different speeds to the lower gear set that it lives in.

ratters said:
I'd like to hear more about this if you don't mind sharing? First time I have come across anyone mucking around with the low range gears in this way, really cool!
Click to expand...

Me too. Interested! Moreso since I’m planning to pull my gearbox apart again for some maintenance and a 5th ratio change.

Cheers

Bennie
 
You need one of those wheel reductors crazy russians making for they lada cars. :cool:
+68mm ground clearance and 1.68x1 lower gear
cqloibvzi5k.jpg


I saw them in action ,very low gear very good crawling. Subarus need they own version of that or smt similar where you just put special rim on
Or just buy cheapest wrangler model and put there all wrangler rubicon stuff like 4:1 low gears lockers and get cheap rubicon
 
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