Toyota Hypoid Diff / 30 Spline / Longfield CVs

[Astro_Al]

This thread contains the accumulated info I have on the Toy 30 spline conversion for Rover axles. I was going down this route to upgrade my stuff when a set of Mog 404s came along and suited my needs better.

Therefore, I have not run the setup personally. However, I think it is a great route to take if you need stronger axles in your Rover. Since no-one ever talks about it in the UK (has anyone at all done it here???), and I got some queries about it when I brought it up, I thought this might be some useful input for people looking to upgrade their axles.

This is applicable to Defender and Range Rover axles, and could be applied to Series axles (which I had started to do) with a little thought/handiwork.

The basics - what you get:

1. Toyota hypoid differentials, 30 spline, choice of lockers. These are stronger than Rover spiral-bevel geared diffs (spreading the force over more gear teeth). They are available in a range of ratios (more available aftermarket) and with a range of lockers - limited slip / ARB / etc, if on a budget the one to go for is the factory "e-locker" (electrically actuated). The price of a complete brand new hypoid diff set up ready to run with an e-locker installed (in 4.10 ratio) is roughly the same as a bare ARB locker for a rover diff in the UK, but of course you also kiss goodbye to the Rover ring and pinion B) . The best source I found is Jim Christiansen at www.inchwormgear.com . Very helpful guy and the best prices. Other ratios and lockers increase the price, but it is still very competitive.

When choosing diffs, you can use the high-pinion rear (gaining clearance), but the front must be regular (if I remember correctly) since you want to avoid running on the back-side of the gears (reverse rotation) when travelling forwards (for maximum strength).

2. Custom shafts. You need 30 spline shafts to fit the diffs etc. If I was doing this, I'd insist on good spec material - 300m or similar - which you may find rules out some suppliers. Don't part with good money for badly specced aftermarket shafts. Certainly Maxidrive do shafts, and others. It may be possible to upgrade in stages - throw in the Toy diffs, Longfields (see below) and run standard Toy shafts in the meantime (check all lengths, of course). As I understand it, the standard Toy shafts can be considered an upgrade from Rover shaft stuff (but so can a drinking straw...). But in the end, you'd probably want to get some decent shafts to complete the setup.

3. Longfield CVs. See here: http://longfieldsuperaxles.com/ . I think that says most of it. These are well-tested aftermarket CVs. 30 spline for the Toyota boys. I'll leave the strength guesstimation to others who are running them (see the threads - and Outerlimits too), suffice to say they are a very good upgrade.

Work involved:

1. The Toyota diffs fit into the Rover housings with a little work. The main part of which is welding up the stud holes and drilling new ones to suit the Toy diff casing bolt pattern. A cut-out must be made in the casing mating flange for the e-locker to fit (if you go this route) - see links for all required info.

2. Depending on the application, there will be a bronze bushing to make up, just a simple ring for each axle swivel. See the threads for more info.

3. The shafts are custom length, so slot straight in, CVs follow, the final thing is to get some drive flanges. You can either have Rover ones re-splined or use custom ones, or maybe change the bolt pattern on a regular Toyota drive flange (I think you have to turn down the outside diameter just a tad too - see the threads for info).

Some people take the opportunity to 'sewer cap' the diff pan on the Rover housing - that is cut out the old (thin) pan and weld in a bulletproof industrial pipe cap (I think you need 8" diameter - thickness is down to choice, they're all pretty beefy). See the threads for more on this. (Optional).

That's it - nothing too serious to do. Bang per buck it has to be the best Rover axle upgrade out there (and, dare I say, strongest possible?).

Here are the links:

There is a lot more out there, I deleted quite a bit of info when I went for the Mogs. There are some good threads on Outerlimits too, you'll need to do your own searching. Pirate is now non-searchable for non-paying members, so I enclose some links from that forum to save hassle.

From Pirate:

1. http://www.pirate4x4.com/forum/showthread.php?t=73972

2. http://www.pirate4x4.com/forum/showthread.php?t=66084

3. http://www.pirate4x4.com/forum/showthread.php?t=255297

4. http://www.pirate4x4.com/forum/showthread.php?t=228292

5. http://www.pirate4x4.com/forum/showthread.php?t=259024

6. http://www.pirate4x4.com/forum/showthread.php?t=297310

7. http://www.pirate4x4.com/forum/showthread.php?t=330274

8. http://www.pirate4x4.com/forum/showthread.php?t=357137

These threads are the pick of the bunch (I think):

1. http://www.pirate4x4.com/forum/showthread.php?t=367387

2. http://www.pirate4x4.com/forum/showthread.php?t=387000

3. http://www.pirate4x4.com/forum/showthread.php?t=360674

Other:

1. http://home.4x4wire.com/erik/diffs/carl_whitmore_email.htm

General Toy diff info:

2. http://home.4x4wire.com/erik/diffs/

A link with a description of the install of an E-locker in a different Toy housing - same principle, plus wiring etc:

http://www.4x4wire.com/toyota/tech/electric_locker/

E-locker cable conversion - in case you fear the electrics (though by all accounts they survive well even in wet use):

1. http://www.pirate4x4.com/forum/showthread.php?t=139172

2. http://www.pirate4x4.com/forum/showthread.php?t=51225

More valuable than a manual cable conversion would be a steel shield for the diff-lock motor in this application.

It *may* be possible that Michele on this forum can help sourcing bits for us Europeans (shafts, flanges, Longfields etc)???

Hope that lots useful to someone...

Cheers, Al.

[Michele]

(...)I was going down this route to upgrade my stuff when a set of Mog 404s came along and suited my needs better(...)

Hi Al,I wondered where you've been gone and now...nice shot!

Can't wait to read your next thread with the conversion write-up!

Since no-one ever talks about it in the UK (has anyone at all done it here???)

Erm,me...almost...I have everything on the floor,but dragging things along sooooo slowly...

Checking and re-checking everything so not to find myself and the Cube stuck in the workshop

Also I'm trying to organize things so my friend Ben (isuzurover) can come for a weekend

and give me a hand.

AFAIK the Cube is going to be the first Rover with Toy CVs here (Italy)...

It *may* be possible that Michele on this forum can help sourcing bits for us Europeans (shafts, flanges, Longfields etc)???

I am the *official* [COUGH]distributor of the components needed to do the conversion.

Forumeers can PM me and I will pass my office email for these parts (got a new job this year and I work now for a LR spares shop).

No direct link so far as I don't want to do free spam here...?

[LR90]

Nice summary Al and good to know with Michele we have a man in our midst that can help with the sourcing.

[jules]

I may be completely wrong but is this the same/similar as the toy diff and portal conversion for land rover axles that the chaps in Brisbane are doing that uses TC not lockers incorporating fiddle brakes as well.?

or am I letting cats out of bags

[Astro_Al]

I may be completely wrong but is this the same/similar as the toy diff and portal conversion for land rover axles that the chaps in Brisbane are doing that uses TC not lockers incorporating fiddle brakes as well.?

or am I letting cats out of bags

If they use the standard axle casings then yes, it probably is, since it is virtually drop-in - plenty of Ozzies run this setup.

Custom portals / volvos / volvo copies / mogs / pinz / rover / maxidrive / other (agricultural etc)?

I hope they're gonna truss the casing though!

Al.

[jules]

I hope they're gonna truss the casing though!

Al.

Yer they do bend easy

[Astro_Al]

Hi Michele - how far have you got with it? If you have any bits machined for your setup, perhaps you could add to the tech here by putting any diagrams or photos or dimensions or anything for everyone to see?

Are you using Toy CVs or the Longfields?

Yeah I guess I'll start a build thread in the Member's Vehicles section. I'm not sure it qualifies to be here any more - I'm racking my brain thinking of a Rover part still in the build...

Keep us posted on the axles! Al.

[Michele]

How far...erm...

Ok,I have all the bits here with me.

I'm just loosing time with the old type sviwels,I only wanted to clean them in the beginning,

now I'm removing the old paint instead and will give some new coats while there,along with the flanges.

Also I have yet to collect the new seals X 2,BTW I got FTC 4785 to have oil bathered wheel bearings.

These are beside my office pc right now

I will probably not modify the chrome balls to correct caster so not to loose more time...

Longs,yup,that's what I'll sell with the kit.

I'm taking pics of the various bits so to do a European writeup when everything's done.

B)

I can't really wait to fit and forget and get out in the woods.

Boredom is killing me.

[Mark90]

BTW I got FTC 4785 to have oil bathered wheel bearings.

I thought it was RTC3511's that where best for oiled wheelbearing.

[Michele]

RTC3511 is 14,56 Euros while FTC4785 is 5,50 Euros.

Other than this I was told the seal is better.

Should I find a RTC3511 around I will give it a look and compare.

[white90]

RTC3511 is the better seal, double lipped

[Michele]

This is double lipped as well,

basically the same but @ cheaper price,or so I understand...

it even says "fit to depht 4mm" and we're going OT BTW

[pugwash]

OK so i have read as much of this as possible but there still huge sections i don't get.

1. Is this likely to be cheaper than going the whole ashrcoft VC/ Halfshafts/ ARB route that everyone else goes?

2. Are the parts easy to get in the UK

3. What real experience do we hav in the UK of running this setup- how does it cope with UK needs as opposed to US or Australian needs?

4. Can these mods realistically be done by failr competent home mechanics?

5. Why are 30 spline typhoid diffs better than the 32 spline Rover Units which are known to be weak? What is a hypoid diff anyway?

6. How much work nees to be done on the rover axle casings and swivels to get evertyhing to work? From the links it seems that very little work is needed- is this right?

thanks guys

Jim

[white90]

OK so i have read as much of this as possible but there still huge sections i don't get.

1. Is this likely to be cheaper than going the whole ashrcoft CV/ Halfshafts/ ARB route that everyone else goes?cost probably compareable

2. Are the parts easy to get in the UKNot as easy as Rover items to get hold of

3. What real experience do we have in the UK of running this setup- how does it cope with UK needs as opposed to US or Australian needs?the American/Aussie useage seems to be large pwerfull engines and lots of wheels in the air hard landings that I've seen on Outerlimits/Pirate, Disco Dino on here has done this conversion to his Discovery without failure to date

4. Can these mods realistically be done by failr competent home mechanics?

yes you'll need some Lathe work to open out the stub axles a small amount

5. Why are 30 spline typhoid diffs better than the 32 spline Rover Units which are known to be weak? What is a hypoid diff anyway?I think you are reffering to 24 spline Rover axles, the Toyota ones are hypoid and the L/R bevel IIRC there is a larger contact area on the Hypoid

6. How much work needs to be done on the rover axle casings and swivels to get evertyhing to work? From the links it seems that very little work is needed- is this right?

redrill the diff housing to suit the Toyota bolt pattern. open out stub axles to allow CV'/shafts to pass through and drill the prop flange to suit the L/R prop

The thing to keep in mind is what are you going to do with the vehicle once built, what sort of power are you expecting to have?

And remeber how easy to get spare Rover bit and pieces is for us in the UK as against Aus/USA/other countries

thanks guys

Jim

[will_warne]

Yeah, what he said ^^^^^

One of the main reasons the Americans and Aussies do this mod is to give you a hypoid diff; the ability to use stronger, toyota style CVs is annother advantge. I think pegging is a better option over here, though. Parts are much, much easier to find. Remember in the States and Aus its often easier to find Jap parts than LR parts. The oposite is true over here. I know some people aren't convinced by pegging but from all the info I've seen/heard a properly built and pegged rover diff should have comparable strength to a toyota centre.

[Michele]

I just hope this is not going to turn into the "war of CVs"...

[white90]

Well on Sunday

I was using both ARB's climbing a 45 degree slope surface slippery with hard base under low 2nd full revs and dropping the clutch to get out of a riverbed turning steering lock to lock, no hint of and probs from the CV's Maxidrive shafts and ARBs fitted.

Since fitting the CV's to complement the other bits in the axle cases I have no qualms about using the lockers/steering input.

There are stronger Axles/set ups available

but for me Keeping it Rover based and simple to set up was high on my requirements list.

Costs:

Maxidrive shafts-drivemembers-£880

ARB's-compressor-£1245

CV's-£450ish

Bearings-diff install- £80 although I'd do this bit myself now.

so by no means cheap,

[SimonPearson]

Well on Sunday

I was using both ARB's climbing a 45 degree slope surface slippery with hard base under low 2nd full revs and dropping the clutch to get out of a riverbed turning steering lock to lock, no hint of and probs from the CV's Maxidrive shafts and ARBs fitted.

Since fitting the CV's to complement the other bits in the axle cases I have no qualms about using the lockers/steering input.

There are stronger Axles/set ups available

but for me Keeping it Rover based and simple to set up was high on my requirements list.

Costs:

Maxidrive shafts-drivemembers-£880

ARB's-compressor-£1245

CV's-£450ish

Bearings-diff install- £80 although I'd do this bit myself now.

so by no means cheap,

....and that is exactly the problem. LR axles are so weak, and you need to spend £2,500 to make them stronger!

This is why so many people are doing Portals or looking into adapting better quality axles (Toyota, Nissan etc) which could work out cheaper and stronger in the short and long term....

[white90]

Simon

not much to be saved when you buy Lockers-shafts-CV's though is there?

there are cheaper upgrades and cheaper deals on ARBs'/Maxidrive gear

now to be had.

plus it is still Rover casings/seals/bearings etc, which are readily available.

I had a hybrid and got sick and tired of going to get bits and pieces

when it was all a jumble of RR/110/S111.

A mate did the Trophee chevenol with a Landie with Toy diff fitted and on breaking a diff was trailered home after a vain attempt to get spares

Billy blew a Ring and pinion and was running again the same afternoon after abrief trip to the nearest town.

If anyones up to it Bathtubs solution is perfect with the FC set up.

[RPR]

Having gone with Volvo portals on my SIII, I have no real opinion on this other than to say how pleased I am to see the discussion on this Forum and that there are plenty of enthusiasts in Europe doing things to increase the abilities of our already impressive vehicles. It's almost as nice as seeing LR fans on the US boards embracing diesel !!! Now if only I could get a good 200tdi over here....

[LR90]

Once item you missed Tony is the R&Ps which you've averted by spending another £X on an Underdrive and I see Will is recommending pegging which is yet another cost to be added if you want to stick with rover parts (and I can see the merit in this).

This makes other options such as Toy centres or Mog/Volvo portals increasingly attractive and much of these are comfortable with 35" and bigger while with all that money invested in our rover axles 35" are still pretty much the limit.

The downside for us in the UK is such items are just not as easy to come by but it only requires Ashcroft or X-Eng to start importing/stocking such items alongside the ARBs and perhaps doing the axle case/stub axle mods on an exchange basis to make it far more accessible. Elsewhere in the world where the Toy parts are more readily available this is as we have seen a bread and butter conversion.

[SimonPearson]

Simon

not much to be saved when you buy Lockers-shafts-CV's though is there?

there are cheaper upgrades and cheaper deals on ARBs'/Maxidrive gear

now to be had.

plus it is still Rover casings/seals/bearings etc, which are readily available.

I had a hybrid and got sick and tired of going to get bits and pieces

when it was all a jumble of RR/110/S111.

A mate did the Trophee chevenol with a Landie with Toy diff fitted and on breaking a diff was trailered home after a vain attempt to get spares

Billy blew a Ring and pinion and was running again the same afternoon after abrief trip to the nearest town.

If anyones up to it Bathtubs solution is perfect with the FC set up.

Well on lockers, no... but with Toyota or Nissan axles you wouldn't need to spend £££ on uprated CV's, shafts etc as the standard otems are so much stronger and better made than LR stuff.

[white90]

I would not change from 3.54 R/P at all.

they are strong enough for the power I have IMHO

Pegging is a thing I would like to have done but the desire to pull the diffs and send them off is very low at the moment.

much bigger than 35's on a Defender become an issue anyway due to the bulkhead outriggers. and the power from a TDI.

if ever I were to need stronger axles the I'd be following Bathtubs lead

[Bush65]

...

5. Why are 30 spline typhoid diffs better than the 32 spline Rover Units which are known to be weak? What is a hypoid diff anyway?I think you are reffering to 24 spline Rover axles, the Toyota ones are hypoid and the L/R bevel IIRC there is a larger contact area on the Hypoid

6. How much work needs to be done on the rover axle casings and swivels to get evertyhing to work? From the links it seems that very little work is needed- is this right?

redrill the diff housing to suit the Toyota bolt pattern. open out stub axles to allow CV'/shafts to pass through and drill the prop flange to suit the L/R prop

...

The 30 spline axles are considerably larger in diam compared to rover axles. The later fine spline, rover axles are tiny by comparison. The bore of the rover stubs need to be enlarged to allow the 30 spline axles to fit.

Rover crownwheel and pinion are spiral bevel. The pinion centreline is same height as the c/l of the crownwheel.

With hypoid gears, the c/l of the pinion is lower (or higher) than the c/l of the crownwheel. The helix of the teeth is much more pronounced than for spiral bevels.

Hypoid gears are much stronger than the equivalent size spiral bevels. Frictional losses are a little greater, but none notice this.

The toy crownwheel (for this conversion) is 8" compared to 8-1/2" for the rover - the rover diff housing can be shaved to gain considerable ground clearance. The diameter of the toy pinion is huge compared to the rover. The length of the teeth is greater for the toy c/w and pinion. The toy gears are much stronger.

As well as drilling the toy pinion flange, the recess in the pinion flange has to be machined to accept the spigot on the rover u-joint flange.

Well on lockers, no... but with Toyota or Nissan axles you wouldn't need to spend £££ on uprated CV's, shafts etc as the standard otems are so much stronger and better made than LR stuff.

The toy hylux cv's are similar size/strength to rover. The Longfield cv's are stronger due to design mods and stronger materials. The strength of the 300M Ashcroft cv's would approach that of the Longfields (IMHO Longfields may have an advantage to some small engineering details).

I assume you are referring to 80 series and onward landcruiser axles as these are the only one that have stronger stock cv's.

Also, only GU Nissan have stronger cv's. Earlier nissans have similar size/strength cv's to rover.

Nissan front axles are similar strength to toy 30 spline. The nissan H233 (233mm dia crownwheel) high pinion front diff (from GQ and GU) is much stronger than the toy diff.

[landmannnn]

Rover crownwheel and pinion are spiral bevel. The pinion centreline is same height as the c/l of the crownwheel.

With hypoid gears, the c/l of the pinion is lower (or higher) than the c/l of the crownwheel. The helix of the teeth is much more pronounced than for spiral bevels.

Hypoid gears are much stronger than the equivalent size spiral bevels. Frictional losses are a little greater, but none notice this.

Am I right in assuming there is a downside to the hypoids?

The rear diff pinion is lower than rover, so if you run a lifted defender the propshaft angles start to get very steep.

A couple of options are to use a front diff in the back (not good since the diff is running backwards) or to fiddle with the angle of the rear diff (messy plus will induce prop vibrations) - this is detailed in one of the links in Al's original post.

This would be less of an issue with longer wheelbases of course.