Transfer case motor - rebuild/re-timing

[kimbl]

I've got a P reg KZN185 with the allegedly "multi mode" 4wd system - generally seemed to work as expected until a few weeks ago when the dreaded flashing lights appeared on the dash. I'd had a few stories from the previous owner about troubles which had taken a while for him to get sorted but as he wasn't the most mechanically minded of owners I'd sort of forgotten it.

So I've done the reading up on the very curious ADD system (http://www.off-road.com/trucks-4x4/t...tem-19259.html), but in this case I'm fairly sure that's working properly - rubber hoses ok, vacumn pressure is fine and it switches neatly when you swap the hoses over.

Next I go looking for the electric transfer case actuator. Find the entirely predictable error of breather hose split at the end on the actuator casing, and just enough water getting in to start to corrode the little contact rings and turn the grease white. Thankfully not totally shot.

I think I got lucky the first time I took the cover off - nothing awful fell out and I managed to clean things up well - reassembled easily enough and apparently worked well - for about a week.

Feeling bold I went back in again for a more thorough clean. Second time not so lucky - the magic spring mechanism which drives the pinion on the rack going into the gearbox has come forward just enough to move on the splines. So I've lost the critical rotary alignment between motor disc and selector shaft rack pinion.

I did try briefly to take the actuator off the gearbox for a proper strip down, but I've aborted that - there isn't enough clearance to really get it off and I don't fancy a transfer case strip to get the actuator rod out. It's gone back on the gearbox easily enough, and I can play with the little sprocket through the cover on the back of the actuator. What I need to do though is re-set or calibrate the actuator so the driven gear rotation matches the actual selector position.

I see several posts on here and other places (eg https://hiluxsurf.co.uk/node/83112) - some seem to get to a sort of solution, others are desparate pleas for parts (https://hiluxsurf.co.uk/node/83061) Most of the threads sort of die out without a conclusion.

I've found a load of Toyota docs on the web - mostly they seem to relate to a similar but slightly later actuator with an inline electrical connector rather than a square six-pin which is what I have. This adds slightly to the confusion as both have six pins but the numbering is different (motor on 1/2 rather than 2/3). There is an excellent Toyota training manual on the whole system which really explains the whole range of transfer gearbox systems (look for 13.pdf) but it is for that later connection and I think mine does just use it for 4wd/2wd - not to move the diff lock as well or range change which later versions of the same system do.

I had a chat with Frogs Island who I think fixed it for the previous owner. They remember the job, but not the critical "calibration procedure".

So - does anyone know the proper procedure? I know Toyota really just say "buy a new actuator - do not fiddle", but I get the feeling this has been done often enough that there is a real answer out there.

I am working towards trying the relay method listed in the Toyota docs for testing motion - then once I've got it at the end of the travel, trying to manually push it into either 2WD or 4WD positions checked with the limit switches then pop the little gear in, but there may well be a better way.

Whatever, assuming I do get to it I'd like to finish this writeup so there is actually a post with a definitive answer that doesn't fade out halfway.

Anyone been in here successfully?

[Overland Tonka]

I was at TonyN place this year and he was doing the same job on a 3rd gen...I sat in the car and helped him (just watching the lights) if...and it is an if....you can contact him maybe he could help.

[kimbl]

Thanks. I'm going to make up a breakout lead this morning so I can see what all the switch rings are actually doing while I drive the motor - I think I follow the logic of what Toyota are trying to do, it's just how best to get the motor into the right place.

[kimbl]

Sadly another day of no progress - the relay method works into 2wd but not into 4wd - and I can't see any logical way it would work given the actual contact layout.

What I think I've got is a multi-mode system with the electric actuator doing the centre diff lock as well as the 4wd clutch, but I've got the "earlier?" 6 pin square connector rather than the later inline connector. As they've changed the pin numbers I can't just use the details from the later manuals.

I've moved the selector shaft in and out on the rack and I'm a bit suspicious of the front one of the two limit switches as I can't get it to really switch cleanly on a multimeter, but I haven't yet taken it out to bench test.

Hummm - frustrating saga continues. Perhaps I'll just move the vacumn pipes to lock the ADD open then I know it can't wind up the centre diff and I can at least move it...!

[kimbl]

More info - I think by combining Toyota docs I have a pinout translation for my "square" 6 pin connector onto the "inline" 6 pin for the 2002 4-runner for which we have some setup docs.

I'll edit this post if anyone has any better info...!

I couldn't find a way of posting a bbcode table - so image version below


4WD ECU Pin Function "Plate" 6 pin inline 6 pin square
8 TL1 L4 3 4
9 TL3 H2 5 6
22 TL2 H4 6 5
TM1 1 3 (+ve = 4wd)
TM2 2 2 (+ve = 2wd)

Hopefully this table is a) right and b) useful to someone else like me with a Multi-Mode 4wd system with the square actuator connector.

What I'm currently slightly struggling with is the shift shaft seems to be in 2wd when pulled fully out of the gearbox (front driveshaft free to turn with the ADD disconnected) It seems to be in 4wd when the shift shaft slides in. This seems backwards to the toyota docs where shift shaft pulled fully out presses the "L4" switch. Hummm...!


Key background
Toyota training manual:
http://www.testroete.com/car/Toyota/...vetrain/13.pdf

And the wiring diagrams for the square plug buried in a mamoth thread:
http://www.yotatech.com/f2/4wd-wont-...01/index5.html

[smurf77]

Hi. Any joy with this ? I've got the same issue

[kimbl]

Yes - I saw your post, but I've been a bit tied up. I'll post this evening.

[smurf77]

much appreciated thanks

[kimbl]

Right...
I don't claim to have an absolute procedure, but having spent rather more time on it than I'd admit, here are the key details

1 - Check all the limit switches first - I thought mine were ok, but actually both of the ones on the transfer actuator were not reliable - sometimes ok, sometimes a few kOhms rather than a real clean switch.
Having dismantled one, I can't see switch cleaner having much effect, despite the posts saying it has for others- there's a really solid rubber diaphragm inside - but what seems to happen is the switch contacts get just enough oxide that they have high resistance - the ECU doesn't pass enough current to keep them clean. The one I dismantled looked spotless inside but was slightly high resistance. I actually fixed one switch by connecting it in line between one clip of a battery charger and a half charged battery (other clip on battery as usual). Pressing the switch completes the circuit - the current is limited to a normal battery charging 2-4A, but the little spark each time you turn it on and off a few dozen times cleans the contacts nicely.

2 - Switch part numbers: I actually looked up my Gen3 chassis number on http://www.toyodiy.com - seems to be:
84222-12010 - switch on actuator nearest gearbox
84222-60080 - switch furthest from gearbox
84222-35070 - ADD front differential switch.
There are few more on the gearbox as well.

I see other posts suggesting 84222-35070 is interchangeable with the rear actuator switch which may be possible as they are mechanically the same - just a different plug moulded on the top, I haven't got that far yet.

84222-12010 is easy to get from motor parts shops - Intermotor 54024 for <£20 is a direct replacement which works fine for me. I haven't found any other sources than Toyota for 60080 - which is why I treated it as above. I did find one reference suggesting 60080 has been replaced by 60081.

You probably already know, but as far as I can tell, the shaft positions are:
* Fully out = 2wd
* Mid position = 4wd locked centre
* Fully inserted into gearbox = 4wd free centre.

This does not to be what is in the otherwise really good Toyota training docs I linked to above - the general arrangement is right, but the sequencing is different on the actual gearbox I have.

With good switches and a clean set of contacts inside the motor, the key thing I noted was the stop block inside the back of the housing where the spring behind the big gear runs. I worked out from some of the order of contact rings and the "relay test" in some factory manuals that this stop is aligned with the 2wd position (with the big gear fully clockwise (viewed from the side it comes out), the tab from the gear hits the stop). This is what people seem to mean by "it has to be right at the end of the travel".

The key realisation was that the pinion is only driven by the spring - so you have to ensure there is a little preload so the pinion pulls the rack fully out against that end stop before the motor gear hits it's own end stop. If you simply pull the rod fully out, then replace the gear and pinion in at that point there isn't enough tension in the spring. You need just a few degrees for the motor gear to move after the shaft has hit end.

So, what I did:
* Assemble big gear, put front cover on.

* Remove little triangular cover on the rack side, and pull out the pinion with a pair of needlenose pliers (careful of teeth etc - it moves very easily if unloaded, totally stuck if trying to force the rod).

* With a couple of wires directly on the motor I drove it clockwise to hit the stop, then back just a little anticlockwise towards the "rod in, 4wd" area.

* With a screwdriver delicately inserted into the rack on the selector shaft I levered to make sure it was pulled right out of the gearbox - not easy - you have to make sure it's pushed the limit switches up properly, which spring against you, but it feels right when it is.

* Then I slipped the pinon back onto the splined shaft from the gear in the triangular hole. Note it is a vernier adjustment - if it won't go in, turn it round - there are lots of combinations of spline and gear tooth alignment - easy to do just fiddle it round until it slides in without moving the rack / rod.


That was basically it- I cycled it a couple of times with the external wires to make sure it would go all the way in, then when it came back the rod/rack stops first and the motor runs for a fraction of a second afterwards - so the big gear turns a little more and loads the spring.

Plugged everything back together and all the "chistmas tree" lights went away....! Joy, celebrations, alcohol .

The problem is I don't have a measurement to set the "little bit forwards again" - it just sort of worked for me - but it's not far - just a touch.

The nice bit about this method is you don't have to keep dismantling the annoying cover on the big gear/motor - you can do it all delicately from the small cover on the back by just taking the pinion in and out - so if you get the position slightly wrong it's quick to have another go. Much quicker to drive the motor in and out with a couple of wires than keep dismantling that front cover!

When right, listening carefully I noticed another detent was clearly there - what I think is the 4wd, locked position in mid range. this was not obvious earlier - and something that made me more convinced it's right.

I'm told Tony (4x4 toys) has done these regularly, but my attempts to get hold of him were not successful before I worked it out myself (I was warned as you see at the top of this thread :-) )

Can you post your link the the 46.6mm method? - I thought I'd read everything ever posted on this subject but I missed that one!

Good luck!

[smurf77]

Thanks for the detailed reply
Looks like I'm gonna have another fun weekend. Waiting for a transfer indicator switch to turn up hopefully tomorrow and I'll post at the weekend with my progress.

Thanks again.

[kimbl]

@smurf77 - can you post the link / thread id to the 46.6mm measurement - I'd be interested to see what I've missed. Cheers Kim

[smurf77]

http://www.hiluxsurf.co.uk/showthread.php?t=61237

Not great with computers so hope link works. I found it on here

[smurf77]

Does that look like the alignment of the gear when you put it back in Kim?

[BeratE]

Thanks for posting this. I have so far kept myself from opening the actuator, and now with your description I have a very good reason for doing so! If/when I need it though, I am sure I will appreciate your struggles

[kimbl]

Hi Smurf77. Unfortunately I don't have a photo of the position as I put it in for the final time. I do have a photo from a while back, but I think that's wrong so I won't post it to avoid further confusion!

I think I can make sense though, from two points.
Firstly - electrical contacts.
I've posted another copy of the photo you linked to, with some extra numbers on - starting with track 1 as the inner, out to track 4 as the outer.
I've put a black line across approximately where the contacts go - horizontally on the right hand side.

Looking in what I think is the correct Toyota manual (pic posted) there is a procedure showing pins 4 and 5 in 2wd and over the page not included in my post is 4 and 6 connected in 4wd. (I'd happily post the PDF, but it's over the size limit).
From my table posted above, pin 4 connects to contact ring 2 and pin 5 connects to contact ring 3. The only place on the whole gear that rings 2 and 3 can be connected together is a with the gear a touch clockwise (maybe 20 degrees?) from the position shown in this photo. So that's got to be the 2wd position.
The specified 4wd test position is about half a turn anticlockwise - look round and ring 2 appears again about the 8:30 position. That makes sense given the amount of movement I've seen.

So, if the gear is put in as shown in the picture, and then the rack is pulled fully out and the pinion is assembled onto the splines, you could drive the motor just a little further clockwise until the contacts get to the ring 2 to ring 3 position mentioned above. That would have the preload I was on about. Seems to work to me.


Secondly - from memory - I think the "spring hits hard stop" position when rotating clockwise where I actually assembled mine was a little further clockwise than the photo shown. Remember after assembly I drove mine with the motor hard into the stop then "back a little" - could well have approximated this position shown.