Diff upgrade options Mk9

[superclarkey]

Hey,

Got a UK mk9 with 2.8 6AT with what I believe is 3.909 ratio diffs.

Wanted to know what options for a ratio change between 4.5:1 to 4.8:1?

Is there any factory ratios that will fit my vehicle?

I presume I only need to change the front and rear diff crown and pinions.

I will do all the work myself to swap them over.

[dave g]

There is more than just changing the gears you have to set the back lash and the contact points on the gears get it wrong and you will be doing it all over again

[superclarkey]

Appreciate the concern, but I will have no issues rebuilding them as long as I have the parts and they are comparable.

All I’m lacking is what parts to order.

Anyone know?

[superclarkey]

So there is options available to upgrade the diffs at the moment?

[hiluxxury]

Looks like nitro makes some options:

https://nitro-gear.com.au/products/ring ... .75-430-OE

x2 regarding the concerns raised about regearing. I do the work on my diffs, but its not an easy job. Plenty of rubbish out there in the internet on how to do them... but google zuk - he is/was a diff builder in the US who had a huge catalogue of step by step toyota diff builds on his website.

[superclarkey]

Thanks for the link, I can’t get over the price for a c&p, that’s mental.

I didn’t want to say above as I didn’t want to come across full of myself, but I actually run and own a motorsport garage here in the uk, and we build race diffs (be it for skylines, supras, bmw m3’s etc) so we have done enough diffs and have the tooling to do this job properly. So hopefully that puts everyone’s mind to rest

I clearly just need the parts and everything else should be fine.

[hiluxxury]

Yep, the prices are mental. Have a look at suppliers in the US - we pay an Aust tax here for most things. Looks like as i suspected, the tacomas use the same diffs.

No problems at all... we get a few here who think a diff rebuild is a simple job.

[superclarkey]

Haha yeah defo agree its not simple job, even when you've done a fair few you still question yourself at the end as reading the patterns can be somewhat open to opinion.

The price just seems high compared to sub £1k motorsport crown and pinions i buy, just seems a bit sillly when at that price you may as well put a winters quick change under the back

[hiluxxury]

Pretty sure they we're cheaper pre covid and the culture of business/retailers taking a gouge out of everything.

Much better prices in the US:
https://eastcoastgearsupply.com/c-12071 ... -8-75.html

[superclarkey]

So are the c&p 8.75" on the Hilux? (Presume that is the rear, is the front a different smaller size?)

Trying to get some of the basics nailed down so I know what I'm looking at.

I checked my truck and its defo a 3.909:1 ratio.

[hiluxxury]

best to cross check part numbers. east coast gears have a good reputation so might be able to answer that for you.

[superclarkey]

I have sent east coast gears a message and await a reply.

I spoke with my rep at ARB as I’m a authorised ARB supplier in the UK so get allot of discount on the air lockers, they have come back to me saying the following they can supply..

RD132 for the rear
RD111 for the front

Any one know any more detailed specs on these vs the factory carrier sizes?

[superclarkey]

East Coast have replied to me a few times but I think they will be unable to help me as they can't match anything up to work with my truck.

So back to the drawing board.

[Rob_Wood]

So back to the drawing board.

ONLY Because you're "back at the drawing board" ... Have you considered a custom build? Or maybe getting the ratios you're after from another vehicle, maybe not even a Toyota? I kinda feel that if you're doing diff' builds regularly, then you should be able to come up with something that suits AND that if you feel you need an engineer to sign it off, then you probably also have the contacts to make that happen as well.

[superclarkey]

So back to the drawing board.

ONLY Because you're "back at the drawing board" ... Have you considered a custom build? Or maybe getting the ratios you're after from another vehicle, maybe not even a Toyota? I kinda feel that if you're doing diff' builds regularly, then you should be able to come up with something that suits AND that if you feel you need an engineer to sign it off, then you probably also have the contacts to make that happen as well.

If this was some race car that I was offering as a service, then yes of course I would go out of my way to find something that worked, even if it means buying and stripping stuff down and physically trying it, basically R&D. However my business isn't around 4x4 vehicles so I lack the contacts to get the right responses and to really get into this I would have to strip my vehicle down and render it unusable while messing about etc. Hence why if there was a simple solution then great.

I've been open about the fact these vehicles are not my speciality, however a diff is a diff, which I know.

Something that might shock you to know, in the UK we do not need to have anything tested or signed off, I can basically do whatever I want to the car as long as it passes a basic MoT test, which is emissions check, make sure the vehicle is safe to be on the road and it has screen wash in it lol... they don't care about changes to the vehicle.. I could put a LS7 in it and they wouldn't care. Point is, I don't have to concern myself with things if it will pass anything. (only thing we can't do is buy a bull bar for the front, as its a bit overkill for a fox or badger lol)

With all that said, I will want to exhaust all my options of just "paying the bill" and ordering something that will work, before wasting my time on trying to find a solution etc.

I'm sure I would be able to make a rear diff from scratch, but I've never done one as not many vehicles I work on have solid live axles and if I'm going to that trouble I will be binning off the leaf springs... Hardest thing sometimes is to not go to crazy because if I get started it will end up like a Dakar race machine lol

The fact I have to reach out to what is basically an Aussie forum to get info says everything you need to know about how popular these vehicles are here lol No one that I can find is really modifying them at all.

[Rob_Wood]

A quick google search for "Diff Ratio Database" returned a bunch of sites. This one stood out as a resource that might be able to help you. I only looked at page one of the search results, but I feel confident there'll be more useful results if you take a gander.

https://www.vmn.com.au/resource-centre/ ... ota-hilux/

Hope this helps.

[superclarkey]

Thanks for the link, I already read that page before I put this up, why I didn't think it was relevant is because it states upto 2015 model, being as its the previous model.

I have read pages of results and after that still found the need to start this tread as there was no clear cut answer, so unless I've missed something the info is not easily googled.

I'm hoping someone that might know something might yet to see this thread, so its hopeful someone comes to the rescue and saves the day here.

[Rob_Wood]

I'm definitely not very knowledgeable on Diffs and am only offering general ideas to help. Maybe if you contact the web page company they might have additional information that's not posted on the website? Just a thought.

The other thing to consider is that the diff in a 2006 model should not be too difficult to fit into a 2020 model and vice versa, especially if both models are using leaf springs, or maybe both are using coils? Not sure, mine is 2004 and uses leafs. Just a thought.

[superclarkey]

I appreciate the help, just letting you know that I have done about two weeks of research before doing this thread so wasn’t a spur of the moment thing I without doing some background first.

I don’t want to order things with my fingers cross it will work as that could be costly mistake.

There is more to just crown ring size when specing a diff, you could have interference issues due to the case, specially if the elocker is different.

I will keep researching and I will report back incase anyone is interested.

[Rob_Wood]

Yeah, I think we can agree that you're already way ahead of me with "Diff' Knowledge". The only other thing I might be able to suggest is to contact a "Diff Specialist", but from some of your comments it sounds like you might actually be a Diff' Specialist, maybe search for specialists in other country's? See if maybe you can find something down that path?