With the driving I've been doing lately, I've been considering switching to a full-time 4wd with locking center diff. I've been doing a LOT (sometimes 50 miles/day, 5 days a week) of gravel and dirt roads, too loose for 2wd, too solid for 4wd. I've been searching the forums for information about these transmissions, and the posts I've found mostly seem to be from people who have never seen one, as most of the information is directly contradictory... so I'm hoping to get some solid answers.

What I want: 5spd full-time 4wd with locking center diff, 1.59:1 low range, 3.9:1 final, widest 1st-5th ratio possible. I'm in the US.

Some posts say only the RX had full-time with locking center diff, some say also the XT6, while others say any ea82 turbo might have one. How to identify them is utterly unclear, either from looking at the transmission or at the interior of the vehicle, with no one apparently ever having actually seen one or otherwise giving a useful description. Some posts say they only came with 3.7 final, others say half of them are 3.9. Most say they have a poor (1.19, 1.2, etc) low range, but some say the 1.59 is a direct swap, some day it's not, some say you need au-only gears, and one even says 4spd parts fit, while I'm rather sure they do not. Some posts say that if you get a 3.7 you can swap the 3.9 pinion from an EJ box in, others say you can't, while some say you need XT(6?) parts. Some say it's a mechanical shifter, others say it's electric. el_freddo has a post saying nothing swaps without welding, but his posts are specific to a dual-range EJ tranny that's not available in the US, while I'd be using EA82 parts. Some posts say I'd need three transmissions, an RX, an XT6, and a non-turbo dual range.

My current 5spd dual-range is in need of a rebuild (multiple bad bearings, input shaft wobbles an eighth inch, something clunks like a rod knock when in neutral, 5th->R lockout sometimes requires going all the way to the left then back to get to 4th, selector sometimes jams, synchros aren't the greatest, leaks from every single seal top and bottom and back and front...), so I wouldn't feel bad using it as a parts donor for the low range gears.

I've tried doing a couple searches, and couldn't find anything available that looked like a full-time box. But, I don't know. car-part.com lists the full-time separately and says there's two available, but I think it's just lumping all ea82 transmissions together.

So... What parts do I actually need? How do I identify them, either looking at the transmission or at the car it's in? Are they even available at all?

Edited yesterday at 04:27 AM1 day by bushytails

I'm not here to answer your questions, because I don't have the answers. I know you're in for quite a bit of searching and just as much work, but I can offer some help potentially finding parts.

I know for certain my parts guy has a fulltime 4WD Turbo wagon. Problem is that I'm 99% sure it's a 4 speed auto. But the next time I'm over there (probably early June) I can take a look at all the cars he has and see what's available. He's trying to get rid of the parts and would like to know the parts are actually being used.

Good luck though, if you can source everything it'd be a trick piece of kit!

:]

Definitely don't want an auto. lol. 5spd dual range for sure...

I'm at the point where the more forum posts I read, the less I know, due to conflicting information...

What you could do is look for options package pamphlets on eBay or the like. They may provide some insight as to what was offered from the factory. Could also get some RX and XT informational pamphlets. Just an idea.

Rob Allen may offer some insight.

Wizard of the RX ;)

G’day @bushytails

The L series AWD locking centre diff gearbox came in the RXII coupe, some XT4s and JDM GT wagons. I’m unsure about the XT6 - we didn’t get them here, infact all of these models except the XT4 were personal imports.

How to tell them visually apart from the single range PT4wd gearbox with the vacuum actuator to engage the rear drive:

• this PT4wd single range gearbox’s lever to engage the rear drive is arm above the pivot point.

• The AWD locking centre diff gearbox is the opposite - the arm is below the pivot point for the locking centre diff engagement. I believe the dual range version will have the rods passing through the rear housing like the DR PT4wd gearbox.

The AWD gearbox comes in single and dual range. Pick the one you want as it’s not easy for you to swap it to dual range without another dual range AWD gearbox (EA or EJ).

The 3.9 ratio is out there from what I’ve heard, it’s hard to find. Mine was a 3.7 ratio.

All of these dual range AWD boxes are 1.19:1 low range. The 1.59:1 transfers in without any issues, it’s a direct swap - need a donor NA dual range PT4wd gearbox.

The EJ AWD gearbox pinion shafts are too short. I heard of a bloke that modified two of them to make one pinion shaft for the L AWD locking centre diff gearbox to get 4.44:1 diff ratio - to do this with the good L series low range requires the crown wheel to be shaved to clear the low range selector ring and gearset. I have not seen pics or videos of this done (the double EJ pinion shaft to make one L series AWD pinion shaft).

From my understanding, L series PT4wd gearbox internals do not swap over to the AWD version, other than the low range. Everything will physically fit but it’ll become a part time box that requires the part time rear housing as well.

My gearbox is made of EJ parts (drive gears and front cases) and the L series AWD bits for the locking centre diff and 1.59:1 low range.

Ultimately if you’re on dirt that’s somewhat loose, you want to lock your centre diff, especially if EJ’d as it’s very easy to be spinning the front wheels faster than the rear, over working the centre diff that will lead to its destruction. You could be better off sticking with the PT4wd dual range box, the AWD is only worth it on solid surfaces.

^ PT4wd in the foreground, AWD in the background, you can see the locking lever on the side here with the pivot point above the arm.

I don’t have any better pics than the above sorry.

I believe the dual range AWD gearbox is fitted with the same rod looking setup in the background of the gearbox as the PT4wd gearbox. My dual range AWD gearbox is built from a single range box originally, so my rear housing lacks the rods that I believe pass through the rear housing for the low range dedents/position retainer setup.

Make sure you get the vacuum actuator and it works, plus the matching vacuum switch solenoids too, or have access to them. The single range PT4wd gearbox units work fine with the AWD box ;)

I hope this helps.

Edited 1 hour ago1 hr by el_freddo
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