Question about gearing, 3.70vs.3.90vs.4.11vs.4.44

[superu]

So I want to clarify something about gearing in my head regarding final drive and what it means in terms of general performance.

 

So as motors have gotten more powerful through the generations from EA71 81 to EA82 to EJ22, EJ25, EJ20 and EJ25T gearing has also been changing.

Older rigs had 3.70 (maybe different even earlier than early 70s gears, I don't know) then 3.90 and 4.11, and the SVX and or RX (I think) had something weird and unique, but finally i guess there is 4.44 gears.

 

So there's talk of taller gears and shorter gears. Am I correct that as the number gets 'larger' the gear gets shorter? So 4.44 is shorted than 3.90? And what does this mean in terms of output to the ground?

 

Would taller? gears like 3.70 and 3.90 be set up for top end, or lower RPM at higher highway speed, but shorter? gears like 4.11 and 4.44 be higher RPM at high speed bu more torque-y to the wheels?

 

So, for example, given a NA EJ25 running 3.90 5MT, would that have slightly lower RPM at 70 in 5th than the same motor running a 3.90 5MT at 70 in 5th (all things being equal, like tire diameter, model, weight, etc.)?

 

Am I on the right track here? If not please show me the light.

 

Here's what's fueling my questions, and it's been mulling around in my head for a few years, touched on here and there by this thread or that thread but maybe not ever so directly approached. . .

 

I'm running a NA EJ22 5MT with 3.90 final drive. I've upped my tires from stock 185x70x14s to 27" At's. I've done some calculators online and think to compensate for the increased tired diameter (and maybe weight), I'd need like 4.54 gears to regain "stock" driving characteristics.

 

To compensate for these taller tires I think I can regain more stock-like driving (e.g. stop to go acceleration) characteristics by going with an Ob transmission (5MT 4.11 final drive), or maybe even 4.44 final drive, although I think those trannies may be higher $$ compared to first gen OB 5MTs (and some have even said first gen legacies ran 4.11 final in their 5MT)...

 

? ? ? hep me clarify . . .

thanks!

[idosubaru]

to clarify, most of what you're mentioning is "final drive gearing" related, not just "gearing" related. 3.7....4.44 is all final drive specific. the gear ratio of the actual gears inside the transmission also make a difference, not just the front and rear diffs that determine the final drive ratios.

 

it might be the case that all the 3.9 and 4.11 EJ MT's use the same gearing in which case the only change is the final drive of the diffs, but i know across some they did change the gearing too (not just final drive). might want to check the nice rallispec...or whatever chart that is that breaks down all the MT gears and ratios.

 

pretty sure only automatics came with 4.44, so your choices in manual transmissions will be (not counting the 6 speed MT, not sure what that has, but i would assume that's cost prohibitive):

 

3.7 (unlikely) so 3.9, and 4.11.

 

maybe it's possible to install a 4.44 front diff in a manual trans, i'm not sure how the ring and pinions shake out between the front diffs but that's a rather big job requiring splitting the transmission case.

 

hopefully the offroad guys see this, they should have some good input.

Edited August 12, 2010 by grossgary

[renob123]

My 6MT has a 3.90 final drive, but it has shorter gears. As Gary said, final drive is not the only thing that matters.

 

To do what you'd want, you'd probably have to keep your transmission and swap the final drive to 4.44. Just swapping transmissions with 4.44 final drive won't cut it, because they change the gearing a little to compensate for it. I'm basing this on some gear ratio spreadsheets someone sent me a long time ago.

 

4.44 final drives are available in Japan in manual transmissions. I also hear you can buy the stuff at the dealership in the US. mellow65 mentioned something about it over at NABISCO.

 

Jacob

[bheinen74]

i think my leg SS would benefit having the 3.7 fd of the RX....with diff lock and lsd

 

would probably go from my 23.5/24mpg to maybe about 27.5/28mpg on the highways...... and still have plenty of get up....)

 

I like the way my SVX drives with the fd of 3.54. it cruises at 80mph at about 2100 rpm lol getting the 27.5mpg that it does on avg. if you leave it in 3rd gear, cruising at 80mph is about 3600rpm i think last i checked, so redline of 6500 is a long shot....

[subaru360]

The forester XT had 4.444 gearing so you can buy it here.

 

Easiest way for you to understand it is the higher numerically you go, the faster it will accelerate, but top speed will decrease.

[superu]

The forester XT had 4.444 gearing so you can buy it here.

 

Easiest way for you to understand it is the higher numerically you go, the faster it will accelerate, but top speed will decrease.

 

That sums up what i was thinking! Thanks subaru360!

 

 

Grossgary:

 

Good point. i do have that MT spreadsheet and have also found similar gearing info from the EA82s (for when i was thinking of a 4x4 swap)... But doesn't the final drive calculate with ALL the gears such that cars with the same geared 1-5 but different final drives would have slightly different driving characteristics?

 

So to compensate for taller tires, should i look at the gearing of cars with stock taller tires, like OB? I think the only difference b/t their 5MT and mine is the final drive. I think my MY 95 had 4.11 as an option, but my rig is with 3.90 final...

 

I think the gearing for 4.44's are different since i think they come in 6MT, maybe some 5MTs out of GTs or FXTs (as subaru360 indicated).

 

 

 

Renob123: are you driving a WRX or STi? I think they, while having 6 speeds, are also 3.90 to give high top end, while the HP and turbo kick up the lower end acceleration.

 

 

 

 

 

Hmmmm, so what you're saying is i could keep my 5MT's gearing and swap out its front diff for a 4.44 diff, and oc caurse the rear for a 4.44 diff also?

 

I have a friend that was going to put a 4.44 in his 02 WRX, but there were different spline counts so he'd have to change his hubs and rotors, etc. etc. Thus he bailed on that idea.

 

I really am looking for a plug-an-play 4.11 (4.44 might be a bit nicer i think)

 

 

hmmmmm

[renob123]

My STI has a 3.90 final drive. It feels like it has short gears because its actual gears are shorter. If you put a 4.44 final drive in it, you'd be shifting constantly and probably be hitting 4,000 rpm on the freeway. The SVX is gear limited to 196 I think, while STIs are limited to 165. Some SVXs came with 3.90 as well. The difference is the gear ratios, not the final drive.

 

I thought only automatic Foresters got the 4.44s here. That's why this conversion is so rare here, and the people that do it order a bunch of stuff from Japan.

 

Jacob

[GeneralDisorder]

As I understood it, there were two years of the Forester XT's with 5MT's that had a 4.444 final drive. So those parts can be ordered here and installed into a number of other 5MT turbo transmissions. The cost is pretty high of course so probably people are getting the stuff used for less from Japan (out of used JDM tranmissions I suppose).

 

Basically, the gearing inside the transmissions stays pretty close to the same within a small range. The final drive is often changed to make the car feel more/less sporty or to offset a larger/smaller tire/wheel combo.

 

But it's not that cut and dried - the differences between say 3.9 and 4.111 is REALLY small. The first generation Legacy (90 to 94) had a 4.111 final drive. In '95 they went to a 3.9 final drive. The gear ratio's in the transmission probably changed a bit as well, but I recently put a 4.111 tranny/rear end from a '91 into a '96 with a dead 3.9 tranny. The difference is not even noticeable.

 

Really - unless you get the transmission gearing AND the diff from something like an Outback, etc where the final drive was actually modified to offset the larger tires then you aren't going to affect much change by changing only the final drive ratio. You have to look at the total package and how the gearing inside the transmission is setup AS WELL as the final drive. The end result is what matters and there's a bunch of ways you can get there. Very tall gears inside the transmission will still make a car slow even with a high final drive ratio, and very short gears will make it fast and with no top-end.

 

The final drive ratio is chosen mostly for what it will do to first gear - which is nearly always very similar on all transmissions. If you want something that *jumps* off the line (or to correct for larger tires) then you choose a higher number for your rear diff. If you want a more economical and reasonable acceleration then you choose a lower number.

 

GD

[superu]

Ahhh. I see it's not so simple. Hmmm, so my first instincts of getting an OB tranny were pretty good. Now to refine and figure if its 1st gen or 2nd gen OB, and how foresters would also factor in. . . AND to complicate it all, i'm interested in an Australian Forester transmission, maybe from an XT, but not positive yet. . .

 

So to compensate for my taller tires in an otherwise stock 95 3.90 5MT, I'd be best to get the whole package (i.e. tranny and rear diff) from a rig that had a taller tire setup, like an OB or Forester?

 

AND just swapping my front and rear diffs for say 4.11 or 4.44 wouldn't do so much as a whole tranny final geared as such (remembering all gears are more set for the setup I have created)?

 

I do have the Subaru Manual tranny chart (but can't seem to attach it) and have found gearing from earlier generation manuals.. So I could review the 1-5 gearing of what I think I'm looking at (5MT forester XT) vs. my leggo...

 

This thread is clarifying my questions about final drive as relates to 1-5 gearing (which i hadn't considered in my thoughts before)...

 

Hmmm:rolleyes:

 

 

As I understood it, there were two years of the Forester XT's with 5MT's that had a 4.444 final drive. So those parts can be ordered here and installed into a number of other 5MT turbo transmissions. The cost is pretty high of course so probably people are getting the stuff used for less from Japan (out of used JDM tranmissions I suppose).

 

Basically, the gearing inside the transmissions stays pretty close to the same within a small range. The final drive is often changed to make the car feel more/less sporty or to offset a larger/smaller tire/wheel combo.

 

But it's not that cut and dried - the differences between say 3.9 and 4.111 is REALLY small. The first generation Legacy (90 to 94) had a 4.111 final drive. In '95 they went to a 3.9 final drive. The gear ratio's in the transmission probably changed a bit as well, but I recently put a 4.111 tranny/rear end from a '91 into a '96 with a dead 3.9 tranny. The difference is not even noticeable.

 

Really - unless you get the transmission gearing AND the diff from something like an Outback, etc where the final drive was actually modified to offset the larger tires then you aren't going to affect much change by changing only the final drive ratio. You have to look at the total package and how the gearing inside the transmission is setup AS WELL as the final drive. The end result is what matters and there's a bunch of ways you can get there. Very tall gears inside the transmission will still make a car slow even with a high final drive ratio, and very short gears will make it fast and with no top-end.

 

The final drive ratio is chosen mostly for what it will do to first gear - which is nearly always very similar on all transmissions. If you want something that *jumps* off the line (or to correct for larger tires) then you choose a higher number for your rear diff. If you want a more economical and reasonable acceleration then you choose a lower number.

 

GD

Edited August 16, 2010 by superu

[Gloyale]

AND just swapping my front and rear diffs for say 4.11 or 4.44 wouldn't do so much as a whole tranny final geared as such (remembering all gears are more set for the setup I have created)?

 

To clarify, you can't simply swap the front diff.

 

the Ring gear must match the Pinion.

 

You would need to use the entire pinion from a trans with a different ratio. And since a few of the gears are casr into the pinion, you're limited to using ones that have the same ratio gearsets.

 

Every tooth counts:rolleyes:

[renob123]

Ahhh. I see it's not so simple. Hmmm, so my first instincts of getting an OB tranny were pretty good. Now to refine and figure if its 1st gen or 2nd gen OB, and how foresters would also factor in. . . AND to complicate it all, i'm interested in an Australian Forester transmission, maybe from an XT, but not positive yet. . .

 

So to compensate for my taller tires in an otherwise stock 95 3.90 5MT, I'd be best to get the whole package (i.e. tranny and rear diff) from a rig that had a taller tire setup, like an OB or Forester?

 

AND just swapping my front and rear diffs for say 4.11 or 4.44 wouldn't do so much as a whole tranny final geared as such (remembering all gears are more set for the setup I have created)?

 

I do have the Subaru Manual tranny chart (but can't seem to attach it) and have found gearing from earlier generation manuals.. So I could review the 1-5 gearing of what I think I'm looking at (5MT forester XT) vs. my leggo...

 

This thread is clarifying my questions about final drive as relates to 1-5 gearing (which i hadn't considered in my thoughts before)...

 

Hmmm:rolleyes:

 

Yeah, that's what I was trying to say before. It's how the whole thing is setup. If SVXs and STIs have the same final drive (for the most part), then how is the SVX gear limited at 196 mph vs. 165 for STIs? Blindly grabbing a setup with the final drive you want may be disappointing. Imagine having a FXT and wanting better gas mileage. You could see an STI 6-speed with 3.90 final drive and think it would help. You'd be wrong because the actual STI gears are shorter.

 

Also keep in mind that Subaru went to RA-width gears around 2004 or so.

 

Jacob

[superu]

So here is some data:

the US info is from the tranny chart that floats around here and the AUS info is from a tech bulletin (http://www.subaruforester.org/vbulle...03-04-a-34149/). The EA82 info I got here somewhere, sometime ago.

 

Am I reading this correctly? The USDM forester is geared identically, save reverse and FD, to my 3.90 FD 5MT. The AUS forester (NA) is geared a touch shorted in 1 and 2. US EA82 is geared way shorter in 2-5 than my 95 legacy...

 

Are these the numbers we're talking about that help determine driving characteristics, rather than just FD? And these are also tunied to stock tire diameter, etc?

 

(problems with formatting this gives year and model 1st, 2nd, 3rd, 4th, 5th and reverse, FD and notes)

95-96 US leg 3.545 2.111 1.448 1.088 0.78 3.416 3.9 push clutch

97-99 US OB 3.545 2.111 1.448 1.088 0.871 3.416 4.111 push clutch

99-04? US FOR 3.545 2.111 1.448 1.088 0.78 3.333 4.111 push clutch

AUS Forester 2003X 3.454 2.062 1.448 1.088 0.78 3.333 4.11 1.196 low range

AUS 2004XT 3.454 1.947 1.366 0.972 0.738 3.333 4.44 no low gear

US EA82 85-89 5spd 3.545 1.947 1.366 0.972 0.78 3.416 3.9 1.592 low range

US EA82T 85-89 5spd3.545 2.11 1.448 1.088 0.871 3.416 3.7 1.196 low range

Edited September 14, 2010 by superu

[987687]

When you're going back as far as the ea engines you also have to take into consideration the power those engines were putting out. The ea82 only pushes 90hp or something so it NEEDS shorter gears in the transmission to be able to move the car at any decent rate. Acceleration or speed. Then take the RX with the 3.7 FD. It had a turbo so it has the power to go along with a higher FD ratio.

Also the ea cars (and none of this really applies to the XT6) had 13 inch wheels. Smaller wheels = more revolutions which means it needs a higher FD.

 

You're correct about the EA trannys having shorter gears. But with the bigger tires on my GL 5th gear actually ends up almost exactly in the same place as it does in my legacy in terms of RPM vs speed. Both have a 3.9 FD. Some of the other gears are a little taller, some are a little shorter, but the gearing in the subaru trannys has changed quite a bit over the years.

 

And I thought only auto trannys in the US had the 4.44 FD. I've always been under the impression that the OB and fozzy had the same gearbox/FD. The EJ boxes do like to play with 5th gear though, there's a few different ratios for that.

[superu]

so the reason for posting 1st gen OB, EA82, 95 leggo (my rig) and the AUS 03-04 Fozzies is those are kind of the transmissions I've been toying with.

 

I've considered the EA 4x4 swap and think I'd get a torquey drive, but that's also FWD, the 4x4 would probably be torquey as well, also a locked center and real 4x4.

 

How would those gears act across the same motor?

 

any ideas?

 

* I think the shorter FD (4.11 vs. 3.90) would be higher RPM at highway speed? is this correct?

 

* And would that 4.11 FD allow a little more torque on acceleration?

and how would it play out when combined with a taller? 1 and 2 than my 95 leggo (see next point)

 

* Also curious how the AUS 03 Fozzie's 1 and 2 (3.454 2.062) would play out

 

* My 3.9 5MT and the other US transmission listed have the same gearing listed from 1-5 (except EA82's 2,3,4; 97-99 OB's 5)..

 

I'm kind of hoping for more torque/acceleration in the low gears (1 & 2) and a decent (i.e. NOT 4K) RPM at 70 MPH in 5) RPM at highway speed.

 

thoughts/ ideas??

[obk25xt]

Wow, good read and lots of good info! I can't add much besides this... I have an 08 outback 2.5xt limited with a 5mt and it is 4.44 final drive (it's also for sale btw). So, there are USDM subies with a manual trans and 4.44 FD. Hope I'm not putting out info thats not necessary! Thanks, Spencer

[superu]

(As above, but reworded)

Are these the numbers we're talking about that help determine driving characteristics, rather than just FD? And these are also tuned to stock tire size (e.g. 185x70x14, or 215x5516, or 215x60x16 etc?)

 

(sorry it's not more chart-like but this gives year and model 1st, 2nd, 3rd, 4th, 5th and reverse, FD and notes)

95-96 US leg 3.545 2.111 1.448 1.088 0.78 3.416 3.9 push clutch

97-99 US OB 3.545 2.111 1.448 1.088 0.871 3.416 4.111 push clutch

99-04? US FOR 3.545 2.111 1.448 1.088 0.78 3.333 4.111 push clutch

AUS Forester 2003X 3.454 2.062 1.448 1.088 0.78 3.333 4.11 1.196 low range

AUS 2004XT 3.454 1.947 1.366 0.972 0.738 3.333 4.44 no low gear

US EA82 85-89 5spd 3.545 1.947 1.366 0.972 0.78 3.416 3.9 1.592 low range

US EA82T 85-89 5spd3.545 2.11 1.448 1.088 0.871 3.416 3.7 1.196 low range

 

Am I reading this correctly? The USDM forester is geared identically, except reverse and FD, to my legacy 3.90 FD 5MT?

 

And the 04 AUS forester (NA) is geared a touch taller? (is that right from my 3.545 to the FOR 3.454??) in 1 and 2 compared to my 95 USDM 5MT?

AND the US EA82 is geared way taller (with smaller numers compared to my legacy??) in 2-4 than my 95 legacy...

 

So I get confused how the EA82 crowd can get away with a carbed (maybe injected, I'm not sure) 1800CC on 4-6 inch lifts, run 29" and still have the get up and go to turn those tires on and off road in 2 and 4 wheel, while I've got a more powerful engine and have lost some low end by going from 24" to 27" tires (and some minor exhaust and intake resonator mods)...

 

How do the lifted EA82s not get robbed of power as bad as I did? Is it in their taller 2-4 gears??

 

I just don't quite get it, but I'm getting closer

 

Ideas how my rig would behave going from stock tires to 27's (i lost low end there), but going from 3.90 final to 4.11 final (all other gears equal)?

Would it regain acceleration and maybe lose a little highway speed, or just have a touch higher RPM at highway speed?

 

And also how would it go from its 3.90 FD (and stock 1-5 gearing) to a 4.11 FD and a touch taller? (I think smaller number means taller gear right? 1-2 as in AUS NA FOR

(e.g. I think my stock 1= 3.545 vs UAS FOR 1=3.454 and my stock 2=2.111 and AUS FOR 2=2.062

 

 

THANKS FOR INPUT AND HELP FIGURING OUT THIS STUFF!!!!

[superu]

bumping for more input on the difference in AUS 03-04 FOR 5MT gearing vs. US5MT gearing?

 

I think I get it, but want a little more validation..

 

What does a 1st gear ratio of 3.454 vs. a 3.545 mean for acceleration?

And does a second gear ratio of 2.062 vs. 2.111 mean the same?

 

of course this is multiplied by FD so for ease, say they are each 4.11 FD.

How might the driving characteristics change?

[GeneralDisorder]

It will accelerate faster and top out quicker. You will have to shift more quickly. Basically all the gears are shifted down to increase the RPM's in each gear. This puts the engine higher in the power band and means that the gear tops out faster. It means you'll need to shift more often. It's "sportier" for lack of a better word. But it does decrease the top speed that the car can reach (typically not an issue for american driver's as long as it can do 90 ).

 

GD

[superu]

I tend to ask many things in one post, and folks sometimes respond to one part.

 

 

So, GD, your response is for this question?:

"What does a 1st gear ratio of 3.454 vs. a 3.545 mean for acceleration?

And does a second gear ratio of 2.062 vs. 2.111 mean the same?"

So the 3.454 with 4.11 FD will be "sportier" than the 3.545 with 3.90 FD?

I know the difference is minor but in combination with different FD, the difference will compound.

 

It will accelerate faster and top out quicker. You will have to shift more quickly. Basically all the gears are shifted down to increase the RPM's in each gear. This puts the engine higher in the power band and means that the gear tops out faster. It means you'll need to shift more often. It's "sportier" for lack of a better word. But it does decrease the top speed that the car can reach (typically not an issue for american driver's as long as it can do 90 ).

 

GD

 

I like sportier, that'd also mean torque-y-er and with a low gear, gooder for towing with a 5MT..

 

But it does decrease the top speed that the car can reach (typically not an issue for american driver's as long as it can do 90 ). GD

 

I can only get about 95 now anyway, but with a luggy, lagging low end. SO, I read all things better with this gearing combo (from the AUS tranny)!

 

Thanks for your info and help GD, and others!

 

-mw-

[superu]

Sooo, I read more about the OB trannies and people aren't too excited about the high revs on the highway, since I got a 99 OB (would have preferred a forester but wasn't sure why) to swap for my stock 95 legacy's 5MT with a failed reverse gear.

 

The story is that my 95 legacy's 5th is .780 ratio and outbacks (from the top of my head, at least the first gen OB and maybe 2nd. . . I just need to reference the subaru tranny chart to verify that) 5th gear is .871.

 

Foresters have the same 5th as my 95 legacy (.780) and later Impreza RSs are also 4.11 FD withth etaller overdrive 5th gear (.780), starting around 03? Previous RSs, like OBS are 3.90 FD.

 

While small, combined with the 4.11 FD it amounts (crunching the numbers) to about 250 RPM at the same speed.

 

SSOOOO . . . . . . . AT LAST, I answered my question!

My research, the info and number crunching from others and my suspicions are confirmed!

 

4.11s are great with 27" tires!!!

 

 

I don't really notice a difference in the seat, but I sure do in the shifting, more accurately the LACK of downshifting on grades I couldn't pull previously without downshifting in the stock 3.90 FD.

 

Here are some quick pix while driving at various speeds.

 

EJ22 with 3.90 FD, 70 MPH @ 3000 RPM (Actual speed 75MPH but VERY weak 5th gear with respect to hills!)

 

EJ22 with 4.11 FD (99 OB 5MT), 65 MPH @ 3000 RPM

 

EJ22 with 4.11 FD (99 OB 5MT), 70 MPH @ 3250 RPM

 

EJ22 with 4.11 FD (99 OB 5MT), 75 MPH @ 3500 RPM

 

 

YAY for confirmation!!

 

I thought about swapping my legacy's 5th gear. BUT through more investigating (mostly online and picking the minds that know about 5MT internals), I found out 99 trannies had some big internal redesigns and the 5th gear and its bearings might not swap from 95 to 99.

 

Although apparently the 5th gear is NOT in the main tranny case, it's in the rear case (housing the center diff), so that would've made it a bit easier...

BUT, i'd need a press, maybe machining ability if things did't fit, etc. wetc. and so on...

 

SOOOO, I'll happily roll with this OB tranny while I continue my hunt for a dual range EJ (ideally a 4.11, so I won't have to get into the main gears and front diff to swap that out, just the low gear set, depending on the D/R 5MT I end up getting)

 

Soo, thank to all who've helped me on this hunt.

[WoodsWagon]

You would need to use the entire pinion from a trans with a different ratio. And since a few of the gears are casr into the pinion, you're limited to using ones that have the same ratio gearsets.

 

Every tooth counts:rolleyes:

Actually the pinion is seperate from any of the 1-5 gears in an AWD trans. In the EA 4x4 trans, the pinion did have gears pressed on it, but not the AWD ones. So it's not that complicated swapping any EJ transmission to any ratio. You have to set up the gear pattern for the ring and pinion, but that's it.

[superu]

Actually the pinion is seperate from any of the 1-5 gears in an AWD trans. In the EA 4x4 trans, the pinion did have gears pressed on it, but not the AWD ones. So it's not that complicated swapping any EJ transmission to any ratio. You have to set up the gear pattern for the ring and pinion, but that's it.

 

so by "that's it", you mean to swap FD ratios you "just" open the box (transmission main case) and get the ring gear and it's pinion gear out of the front diff?

 

Likewise one "could" change any diff's final drive by swapping the ring and pinon gears, but in practicality why do that when you could swap diffs (axle issues aside)?

[GeneralDisorder]

so by "that's it", you mean to swap FD ratios you "just" open the box (transmission main case) and get the ring gear and it's pinion gear out of the front diff?

 

What he really meant by "that's it" is the R&P setup process. Changing the gears to another set is trivial (open case, put in gears!) by comparison to what must be done after they are in the case - setting the clearances between the two is not something that most people are trained to do or really have the time/patience/equipment to undertake.

 

GD

[bheinen74]

3.54 yay yay bump 3.54

[superu]

What he really meant by "that's it" is the R&P setup process. Changing the gears to another set is trivial (open case, put in gears!) by comparison to what must be done after they are in the case - setting the clearances between the two is not something that most people are trained to do or really have the time/patience/equipment to undertake.

 

GD

 

Right! This is what I thought, not quite the easiest affair.