Here are some photos of my blown diff, after i have finnished repairing it there will be a full blown HOW TO about diff replacement and it will cover the ins and outs of removing the gearbox from the car, it will also have references to my DIY CLUTCH replacement thread. it will be up in about a week, for now, here is the stage i am at........

gearbox
http://i299.photobucket.com/albums/mm292/bellto/16012010943.jpg

pieces from diff, found in g-box
http://i299.photobucket.com/albums/mm292/bellto/16012010945.jpg

broken spider gear
http://i299.photobucket.com/albums/mm292/bellto/16012010946.jpg

crown gear, in great shape
http://i299.photobucket.com/albums/mm292/bellto/16012010947.jpg

other gears
http://i299.photobucket.com/albums/mm292/bellto/16012010949.jpg



overall the box is in a1 condition, it is really really quiet and all gears are smooth, so i am not going to get a dodgy gearbox from wreckes, i am just getting a new diff (if possible)

reserved

reserved for diy

I have an auto diff here, the centre will fit in no worries, you just use your current crown wheel and all is good to go.

Will be watching this space, have you considered putting in a LSD? They are not cheap but if I was replacing my diff I'd put one in while I was at it.
How did you manage to break it in the first place, considering the rest of the box is in good nick? All syncros still good?

Normally when a spider gear breaks like that it means that one wheel has had alot of strain on it and generated a fair ammount of heat causing stress fractures in the metal. A good example of this would be doing one wheel burnouts (not saying that this is what you have done but it is quite common for this to happen as a result of skids)

I have an auto diff here, the centre will fit in no worries, you just use your current crown wheel and all is good to go.


^^this

All you do is swap the auto carrier over with the spider gears in it . Prob cheaper to pick up a second hand auto, the spider gears out of a manual are the same part number as the auto. They carrier bolts staight up to the manual crown wheel and pinion, use the auto carrier on the manual pinion. I have a spare box here with the auto spider gear set up. It worked when i had it in mine, it developed a noise so i have to strip the box back down. Also be careful there is a very small oil seal in the mainshaft of the gear box make sure that is intact before putting it together. Mitsu have to order them from Japan, which usally takes a month. If driven normal the spider gears are ok. when you give them a bit they blow pretty easy, i have blown 9 diffs in 2 magnas.

Also the spider gears from mitsu are $325 each last time i priced them.

well, long story, but i never drop the clutch as it has a hd replacement clutch (thats why the rest of the box is a+ condish.........)
and we have learned from others on here ( cough, kurt) that chirpies = bad, but i got layed off the other day because the business is going bust, everyone was waving me goodbye in the carpark, and i saw my buddy (also has a magna, also got layed off) do the thing with his hands that means (do a fullllyyy siick skiidd brus!!) so my mood just after being layed off got the better of me, gave her a big clutch kick on brand new tyres, drove away, turned the corner, and the rest is history. I immediately felt like a total **** head, but hey, i left my mark.

luckily it was a second job, mainly so i could get a 6g75 sc convertion happening faster, so no worries there.

i will not be getting a lsd because when i do the engine trasfer, i will get a new box then.

and madmagna, i pm'd you

Hahaha i did my last diff chirping into 4th at 6200 rpm. Heavy duty clutches kill the diff a lot quicker. Although i did have a XXhd wrx cover and a 5 puck ceramic button plate.

How did u drive your car to blow your diff.? How many km has the box done.? The 3.0l boxes arnt as strong as the 3.5l i think.

How did u drive your car to blow your diff.? How many km has the box done.? The 3.0l boxes arnt as strong as the 3.5l i think.

all covered in post#8

all covered in post#8

Lol did the diff die after that burnout or a couple days after?

about 100 meters after, then drove for another 30 seconds, and decided there was something really wrong. Put it on a trailer, and the guy that encouraged me (shouldnt have allowed myself to be encouraged:nuts:) towed me home.

oh and btw, the hand hire trailers that are rated for 1100kgs, are all sweet for a magna. :facejump:

Are the diff ratios different from manual to auto, or is it just down to the gear ratios?
My auto revs heaps lower on the open road to my manual.
Would changing the diff in my manual to an auto diff make any difference?

It is your crownwheel and pinion that determines your final drive, this between auto and manual can not be chnaged over

Hi, any one know if the clip is supposed to be like this? i think it is but i dont want to have to pull the gearbox out twice. It is the part that locks into the pressure plate, and then the throwout bearing locks into it.

http://i299.photobucket.com/albums/mm292/bellto/20012010302.jpg

Hmm for some reason pics are not showing up for me...

Hi, any one know if the clip is supposed to be like this? i think it is but i dont want to have to pull the gearbox out twice. It is the part that locks into the pressure plate, and then the throwout bearing locks into it.


looks fine to me from what i can see in that pic

cheers i thought it would (slim, might be because its high resolution, photo bucket seens to time out and will not show the pic if your internet loads it too slowly. Keep refreshing and it will come up.)

Got it now - clip looks normal to me too.

yeah, i thought it was ok, its just that last time when i put the new clutch in, it was attatched to the pressure plate, so when this came out i was like oh no, i have broken something, but then i realised. Just checking so that i dont have to do it all twice.

On a side note. Isnt it cool how all the weight from the pressure plate goes on the 6 little fingers. mmm.

I'm watching this thread with interest - I plan on rebuilding my old transmission with another diff when I get back to Melbourne. I'll probably use the diff from an auto box since those boxes are in higher supply. I know they can be interchanged without too much difficulty. What do you need to do to use an auto diff in a manual box? Do you just keep the same crown wheel and pinion? Is the crown wheel the big one on the outside?

Also, Mal mentioned something when I spoke to him about needing a special tool to replace a diff (some kind of shims). Anyone know anything about this?

yes u need to change the shim thickness if u change diffs the shims determine the preload of the diff bearings...
the mits service manual says to use a micrometer but u should be able to use a depth gauge/dial indicator.

So the thickness is different between manual and auto?

i dont think so, mine was exactly the same. i know you need to re shim your diff if you change to a different diff (lsd etc) because they are a different size. I looked at min when i did it, and saw no reason to. The manual and auto diffs are exactly the same, but the crown wheel of the auto is slightly smaller. The center of the diffs are identical, in interchangeable.

Ah ok, that's bad then since my crown wheel has buggered teeth (that is the big one on the outside right?). Now I'm going to have to source a manual crown wheel as well as an auto diff.

a manual crown wheel will be hard to find. auto diff = easy.
i dont know, but you may be able to get your current crown wheel fixed? i dont know iff you can but im sure someone will., as well as that, depends where your chips are, if there are no crack, i would consult an expert and ask them if it is still usable.

chips cracks pitts all = bad!!! depending on where they are. Really any pitting cracks on the tooth face above the contact line is bad and cracks or chips on the tooth edge DO NOT USE.
we spend hours inspecting gears at work ive seen gears worth $1000's of dollars scrapped because they are just starting to pit.
To my knowledge once a gear is stuffed u cant repair it. new one only way.

Doesnt matter if u change a diff from auto to manual vise versa 2nd hand diff whatever...
if u put a new diff in or even new bearings in u HAVE to reshim it otherwise to risk SERIOUS damage to ure box....
the diff centre/ diff may look identical but its the position of the bearing or each individual diff and how they seat in the case

Its like wheel bearings u have to set a tension on them.... too loose they flop around and destroy the trans case too tight and the diff will seize or destroy the casing... U MUST RESHIM or at least CHECK the SHIMS if u plan on changing the diff

chips cracks pitts all = bad!!! depending on where they are. Really any pitting cracks on the tooth face above the contact line is bad and cracks or chips on the tooth edge DO NOT USE.
we spend hours inspecting gears at work ive seen gears worth $1000's of dollars scrapped because they are just starting to pit.
To my knowledge once a gear is stuffed u cant repair it. new one only way.

Doesnt matter if u change a diff from auto to manual vise versa 2nd hand diff whatever...
if u put a new diff in or even new bearings in u HAVE to reshim it otherwise to risk SERIOUS damage to ure box....
the diff centre/ diff may look identical but its the position of the bearing or each individual diff and how they seat in the case

Its like wheel bearings u have to set a tension on them.... too loose they flop around and destroy the trans case too tight and the diff will seize or destroy the casing... U MUST RESHIM or at least CHECK the SHIMS if u plan on changing the diff

yeah, like i said, take it to an expert, and see what they reckon.
I checked my shims and they were alright, the diff wasn't sloppy or tight. ( i checked by using a drive shaft and putting it through the case and into the diff once it was all in and bolted up. Also i inspected it thoroughly.
Its done just over 2k now, about 1k highway at Highish speeds, and with a full trailer, and car. the rest is stop start and around town., and no problems,
I gave it a good boot while i was still in cairns, so i knew it was working properly, before taking it on the highway.

also, to do with the op, i will get the how to done in a couple weeks, i have just moved to townsville, and i have no internet atm (just checking at uni computers). If anyone has any troubles or wants help, just send me a pm and i can give you my number and help as best i can (i am getting really good at fixing magnas now, haha, make it hard to tell people how reliable and good they are) Or on the other hand post the question in here,

Another thing i have to add is i used nulon 85w 90 (i think) semi synth oil and it works as well as castrol syntrans.
very quiet box, and diff, also super smooth and easy shifting... and about 50 dollars for 4L (i got it free off a mate, same with all oils) but is about half the rrp of 4L of syntrans (around 24 per L). Castrol syntrans is a favourite for this site in manual gearboxes.

Umm, I was wondering if you could put the rest of the guide up please?

pm me for bank details.







lol, joking, i actually lost it when my computer crashed, what exactly do you want to know?

Dont know much about rebuilding gearboxes, might be pulling an auto one apart and having a look sometime. How many parts are interchangeable manual <-> auto? Is it possible to fit LSD to an auto?