Has anyone fitted a ra40 diff in a 86??

[egg_83]

Has anyone had any problems with the diff after fitted? Do I still use the T18 rear 1/2 shaft? Which hand brake cables should I use?

[rthy]

isn't the ra40 diff still a T series? ie: just a T18 diff with different brackets?

[Hen is a total nutcase]

Yes, the RA40 diff is a T series. So you will need the T18 rear section of the tailshaft. Use whatever handbrakes cables are fitted. If they are too long put a spacer under the adjuster nut on the handbrake lever, or use an SV11 handbrake cable front sectioin.

I've heard that the RA40 diff mounts are slightly different to T18/AE86, but can still be mounted up, two of the trailing arms just need to be persuaded a bit. This is unconfirmed and I'd be interested to hear about your results.

Hen

[Jonny Rochester]

A few people have used the RA40 rear end in a AE86. You can also use a RT132 Corona rear end. But niether are exactly the same as a AE86/TE71 so it only sort of fits. You need a adjustable panhard rod, or change the length of your panhard rod with a hacksaw and welder.

[rthy]

apart from the pan-hard rod does it fit exactly?

[darkon]

as far as I know the panhard rods ARE the fit?:S I think you need to shorten the drive shaft tho

[rthy]

the reason why I ask is because I am sure I could get RA40 diffs real easy and cheap but T18 diffs are real hard to get now. Ontop of that custom pan-hards are a 30 min job for me once I am setup.

[Gilly]

Has anyone had any problems with the diff after fitted? Do I still use the T18 rear 1/2 shaft? Which hand brake cables should I use?[/b]

it will fit trailing arms can be tough to get in as the mounts are further apart than an T18 diff. if you were using a 4 link this may (in theory) not be as big an issue due to the extra angle you can have on the arms due spherical bearing joint, don't take that as gospel, it's just an opinion I've hel for a while, never had the time or parts to prove it, logic says it's doable.

yes you use the T18 tailshaft (rear section)

I would try the cables that are with it, if they don't fit use the cables from your 86 from memory they work fine (86 ones)

the housing itself is wider, benefit being you can run a fairly positive offset rim (+10mm +15mm) and still fill your guards.

[///PTK]

Hi,
Have a look at http://www.ae86drivingclub.com.au/forum/index.php?showtopic=757

This is my brothers car. It fits, but two ot the trailing arms aren't 100% perfect. It hasn't affected the handling on his car though.

The panhard rod was a long jobbie, but it may have simply been an adjustable Sprinter one (allowing extra length through adjustment).

An added bonus is avoidance of bullsh#t Takumiu tax associated with T18 diffs.

Cheers

[egg_83]

i finally fitted the ra40 diff today afew things to clear up for every one.
1. ra40 trailing arm bushes dont fit into 86 trailing arms. i used ra40 trailing arms and made a tube to fit inside the crush tube making it the same size as 86 ones.
2. t18 rear half needs to be used
3. 86 hand brake cadles fit and have to be used
4. noltec adj panhard rod fits.
5. spring seats are smaller, springs seem to hold in there ok tho. will be tieing down with wire to make sure
6. trailing arms dont need to be persuaded much.
it worked out cheaper than t18 just more stuffing aroud to fit it.
and have a nob mate there to do all the tightening of the bolts make life that little bit more enjoyable. :2thumbs: thanks KE70briskev

and get one with a sway bar or you'll have to get mounts welded on like i do :rant:

[JDMness]

RA40 Diff
http://www.auto-studio.com/ae86/project/0081.jpg

[stefan]

check diffsnshit section

read more!

[ke70dave]

wow this is usefull knowledge man, thanks for posting it all up egg_83

seems to be a much more reasonable option than goin proper T18 diff, wonder how much a wreckers wants for a Ra40 diff....

also that pic above, has disc brakes, do all Ra40's have disc brakes? or if not what ones did you use?

[egg_83]

no they dont all have disk brakes. mine has drums that are bigger than s series. hand brake works really well :greenbounce:
and you can get ra40/60 diffs for half the price of t18 diffs

[quoccy]

RA40 Diff
http://www.auto-studio.com/ae86/project/0081.jpg[/b]


show off

[JDMness]

:D Your just jealous

[Ru-iki]

Lucky for you guys, I have compared a JDM AE86 Kouki housing to an RA40 one just yesterday. The results are as follows:

Upper trailing arm spacing Lower trailing arm spacing Spring hat spacing.
RA40 519mm 977mm 950mm
ae86 494mm 980mm 930mm

Note: the springs and upper trailing arms are not in ideal positions. Springs are quite elastic and should bridge and flex. The upper arms are very short and sit on a bit of a dodgy angle when flexed 13mm sideways. Id suggest an upper arm cut and weld mod to get it right.


As for the springs:

RA40 springs have a tight wound tapered end whereas ae86 ones have two fat ends. You will need RA40 springs for the diff end as that is the end where the spring tapers. Note coronas etc were very similar and springs will interchange.

As for the trailing arms:

The RA40 trailing arms are identical length units to AE86. Different bushes though. I have taken rough measurements and the cup diameter looks much the same.


As for the forwards or backwards offset of the mounts and how they compare to one another:

The RA has mounts 10mm further forward on the housing for all the suspension arms including the panhard rod. Their relative positions to each other are all much the same, but the RA diff will sit further back using the AE86 floorpan mounts and suspension arms.

As for the panhard rod issue:

Yes the ra40 panhard rod is a different length to an ae86. The pin to mount the rod is in a different position on the RA40 diff, making the rod about 50mm shorter than the AE86 one. Im not sure how the mount on the floorpan will compare from the RA to AE86. I have not checked. Use an adjustable rod.

As for the tailshaft:

Im not sure at this stage about whether you can use the RA40 rear section or not. I measured the length from face to face on the ra40 one, it is 760mm. In my opinion if it is about 10mm longer than a t18 rear section then the RA40 rear tailshaft section will be fine, and will effectively lengthen your wheelbase by 10mm, when used in an AE86. This could be why you have to force it together when using a t18 rear section, since the trailing arms are all the same length from RA40 to AE86, but the RA40 diff is sitting further back due to its mounts being further forwards on the housing.

SOMEONE WITH A T18/JDM TAILSHAFT SITTING AROUND PLEASE MEASURE THE REAR SECTION. My guess is 750mm.


As for the bushes:

The centre bolt is larger on the ra40 bushes/diff. The outer bush cup size is the same on both cars, according to my measurements. Note, I have not actually fitted it yet, but my assumption is I would use an RA40 bush one end, and aa AE86 one the other. Look to the info above for real practical advice.


As for the Swaybar:

The RA40 diff I looked at had no mounts on it. The JDM one does. You will need a welder.


As for the Brakes.

Most RA40 diffs have drums on them. Not sure of their size but I suspect they are slightly larger drums than AE86. Only RA40GTs came out with factory lsd and disc brakes. That diff pictured is very rare and expensive. Don't get your hopes up of finding better than a drum braked, open centre 4.1 ratio.

The width from one mounting face to another is 1410mm on the RA40 diff. Not sure if a JDM diff is the same as I was comparing a housing to a complete diff. Hope this settles a few bets.

[mikewestphoto]

Is that disc braked diff, a RA40 diff with disc brakes put on it or a MA45 diff?

[JDMness]

although the RA40/RA60 diff conversion is cheaper its not as simple as an T18 diff conversion, there are many little changes and lots of measurements, bit of machining of parts etc to make it all fit correctly.

Although that diff in the picture has disc brakes and an lsd its not a RA40 GT diff ;)

[mikewestphoto]

Disc brake set up off corona. I just went outside and had a good look at the Calipers for the F-series.

[julzy]

ST141 discs, calipers, backing plates and bearing spacer (which is attached to the axle retainer) are needed.
They fit straight onto a RA40 diff. You can get a swaybar diff it depends on which year model you get.

For the tailshaft you can use normal things you need for a t series fitment

[egg_83]

iv done it and there is no little measurements it is very straight forward. obviously its not perfect but is a cheap upgrade from a standard s series. use ra40 trailing arms and make a sleave to go inside of one bushes on each trailing arm then they fit fine.

Ru-iki. cups look the same but are different hence the reason i made sleeves to fit in the ra40 bushes.

Im not saying this is perfect just letting people know it can be done. iv got one in my 86 and im happy with it

[JDMness]

well if you want it to be perfect then there are some little measurements and modification to be made ;)

http://auto-studio.com/ae86/project/0089.jpg

I wonder why these springs fit perfectly :o
http://auto-studio.com/ae86/project/0090.jpg

[egg_83]

righto champ. i was pointing it out to people that want to do it cheaply not having to modify mounting points ect. which wouldend up costing more than a t18. and ra60 diffs have swaybars i went and checked one yesterday

[remi]

I did this conversion a couple of weeks back (left my findings on the 'diffs and shit' thread). It works great and is a cheap alernative to getting a JDM T18. As for sway bars. I found an RA40 at pick and say less which had a swaybar fitted to it. There weren't any mounts on the diff but it was mounted with U bolts. Works great and is an even cheaper option to cutting and rewelding yous S series mounts.

My 2c

Cheers Mike

[remi]

oops double post

[kewagon]

i ahve doen teh conversion in my ae71, worked really well, better than the borgwiner, i just cut the old swaybar mounts off the borgwarner and welded them onto the t series, i used an adjsutable panhard rod and a sprinter front half tailshadft and a T18 rear half, stock handbrake cables and welded the centre up, ran it at a drift day and it was fine, best mod ive ever done to my car and i got the diff off my dad for nothing

well worth the little bit of extra effort and the drums are massive= awsoem handbrake

[af300e]

And, what are the chances that a trueno lsd will slot into this? Any ideas? I don't suppose the RA40/60 diffs have the big axles like the kouki?
Thanks
Andrew

[Hen is a total nutcase]

Trueno LSD will bolt in. Any T series LSD will.

RA40 and RA60 use the smaller splines. The only things to use the larger splines are late AE86s (and AE95, but who cares about them, they can't be used).

Hen

[gaz20v]

i have a ra40 I'm using for parts to build up my ae71. i am fortunate to have scored a disk rear end in it, i assume it is out of a ma45 supra?? it doesnt seem to have an lsd (wheels spun opposites in the air) and it does have sway bar mounts (although in the ra40 it hasnt a sway bar).

has anyone used one of these?? i assume it has the same mounting dilemas as the ra40.

[egg_83]

so you pulled it out of a ra40? If so yes it will fit. Ra60 diffs came out with sway bars. As far as it being a ma45 supra diff i don't have a clue

[gaz20v]

yeah coming out of an ra40, in fact coming out tomorrow, i will take some pics to see if anyone can identify for certain if its ma45. only reason i think it is is that the previous owner told me the diff was supra, the only live axle T series i could find reference to having come out of a supra was an ma45.