MY dual range manual gearbox

Cliff R · Post by **Cliff R** » Sun Dec 27, 2015 6:38 pm

About 13 to 14 years ago I pulled the original single range 4WD auto gearbox out of the MY Touring wagon and fitted a dual range 4WD, 4 speed manual gearbox to the car.
Here we are all these years later and I am now experiencing some gear clashing usually from 1st to 2nd up and/or down the gears.
I don't recall off the top of my head the ks now on the gearbox/clutch since I fitted them (clutch was new at the time of install) but the gearbox was 2nd hand from a wreckers what I got it with about a gazillion ks already on it already so wear is no surprise.
The gearbox is a 3.700 ratio which I believe is standard but I am wondering if all MY dual range 4WD manual gearboxes are the same, ie, bolt holes fitting positions etc, same between wagons and Brumbies etc.
Was there a clear definition of any differing of clutches such as between certain years one clutch type/size and between other years a different clutch type/size.
I don't have the time or funds to go the L series conversion and am generally quite happy with the MY box so no conversion is on the cards.
I can keep driving the car for now, it is just not exactly easy to drive all the time.
Anyone in the Newcastle/Hunter Valley with a box they want to part with or anyone anywhere who is in a position get one freighted to me ?
Failing this I will do the round of the wreckers but need to know that the box I am getting will fit and what clutch I buy will fit.
P.S. I have fitted a new gearbox stick bushing kit so this isn't the issue.

Proton mouse · Post by **Proton mouse** » Mon Dec 28, 2015 1:31 am

Having had Wagons and Brumby's I can say that all MY 4sp hi/low boxes are the same bolt up fit, however, they do come in 3.9 as well as the 3.7 ratio.
There are 2 size flywheels, an 8" and 9" I believe (200mm and 225mm) with 2 size clutches that fit the differing flywheels.
Whatever box you get will bolt up to either clutch/flywheel set up, but don't go ordering a clutch kit til you know what size your one is.
Wish you were around Brisbane I'd help you out with one for the right price but I think the freight would be a killer down to you.
Cheers, JB

Cliff R · Post by **Cliff R** » Mon Dec 28, 2015 12:17 pm

Thanks JB, I found my Auto 1 receipt from 2004 (? thought I did this years before then) and I appear to have originally bought
(1 off) R397N - Clutch kit
Then this is showing as (-1) which appears it wasn't right so I then bought
(1 off) R1022N - Clutch kit
Will have to research this as I cant for the life of me remember what happened.
Auto 1 is still in town in the same place with the same (pretty much) people but is now Autobarn.
They will be able to sort the clutch differences out.
If all the boxes are the same I will go looking for as late a model of box I can (Brumby) and get a clutch to suit.
Still no rush as I need to sort funds to get a box and clutch.
Maybe ready to do this in the next 12 months.
Glad I usually keep details of what I do to the car.
Any thoughts on the pros/cons of the 3.7 vs the 3.9 ratios, and were all later boxes 3.7, 3.9 or a mixture.
Obviously, if I change to a 3.9 (think this is what the auto box differential was) I will need to change the diff as well as the box.

steptoe · Post by **steptoe** » Tue Dec 29, 2015 7:32 am

R397N is an EA82 L Series 4WD or FWD Turbo clutch kit NEW

Never come across anything but 3.7:1 4 sp DR boxes in MY Brumbies anyway , but looks like the early EA71 4WD had 3.9 rear diffs ....

Proton mouse · Post by **Proton mouse** » Tue Dec 29, 2015 12:58 pm

Any thoughts on the pros/cons of the 3.7 vs the 3.9 ratios, and were all later boxes 3.7, 3.9 or a mixture.
Obviously, if I change to a 3.9 (think this is what the auto box differential was) I will need to change the diff as well as the box.

My '84 MY wagon had a 3.9 box which lasted several years until starting to crunch like yours is doing, so changed to a 3.7 diff/box I had lying around.
The 3.9 definitely had a nicer, lower range 4wd capability, but the 3.7 used less revs at highway speeds, and so was a tad more fuel efficient.
So I guess it's just up to your own personal preference and what your needs are for the car.
The 4speed D/R are all old boxes now so I personally wouldn't limit myself to sourcing one from just later model cars.
I would be looking for one from a car with a known, low Kay history, or maybe has a receipt for rebuild, or if someone is about to wreck car/upgrade box that you can still take for a test drive before removal.
As Steptoe has said, the Brumbies don't seem to have ever had the 3.9 ratio (unless of course subsequently fitted) so If you are after one, you will have to look to the '82 to '84 wagons.
Cheers, JB

Cliff R · Post by **Cliff R** » Tue Dec 29, 2015 5:59 pm

Steptoe
I don't remember the details but it makes sense with the R397N being incorrect and that would be why I would have taken it back.
This means, it looks like the R1022N Clutch kit is the right one for when I go and order it.
JB
I have been generally happy with the 3.7 gearbox so will, as you say, wont be limiting myself to a late model box but rather look for the low ks etc.
Mind you, the 3.9 sounds like it was better low down so I guess it will depend on what I can get and for what price.