Series 3's and aftermarket diff lockers

[series3]

I was out having a bit of a fang around with my brother in a 200tdi defender and a mate with the same car, main difference is a detroit rear diff locker in the rear of my brothers car.

going along rutted out firetrails and muddy sections after the rain, i could notice a huge difference that the rear difflocker made. the stock central difflock seemed really ineffective, especially when the wheels began to spin when climbing steep rises in bogs and muddy ruts.

it got me thinking, i have a stock series 3 that can go pretty hard in that sort of siutation, but fitting an aftermarket rear difflock would seem to make it go a lot harder. has anyone done this before? is it worth the effort/money?

my understanding is that it would cost around the 2000 mark to get one fitted.

any opinions would be greatly appreciated.

[Phoenix]

Comparing a center and rear difflock are 2 different beasts. A defender with the center diff locked will have the same drive effect as a serites 3 in 4wd.

As to rear diff locks, they aren't particularly common for series vehicles, and I don't know if anybody still makes them. So you have to find one first. Does your series 3 have a saulsbury or rover diff in the back. if it's a rover one a difflock will just snap axles faster.

[series3]

if it's a rover one a difflock will just snap axles faster.

its a stock SWB, which i believe is not the saulsbury. i have heard about the back axles snapping easily, but i didnt really beleive it until it happened.

by the sounds of things its not particularly worth doing to this car, in hindsight it would be much better to keep stock i suppose

[sclarke]

You can buy my Stage 1 with twin ARB lockers for $2500..... cheaper than 1 diff lock...

[Blknight.aus]

ARB make diffs to suit. but thems exxcy

[cmurray]

I would hunt around for one of McNamara's old bolt operated diff locks. You can pick them up for a couple of hundred dollars, and come with 24 spline axles.

[series3]

I would hunt around for one of McNamara's old bolt operated diff locks.

never heard of these, what can can you tell me about them? are they hard to come by?

[cmurray]

I found this image a while ago for another thread:
https://www.aulro.com/afvb/images/imported/2016/02/327.jpg

Hopefully this should explain everything you want to know. You do see them popping up for sale every now and then. You also may want to ask around to see if anyone around you has one they want to sell.

[isuzurover]

As with any 4x4, a locker will make a HUGE difference.

I have a rear Maxi-Drive locker in my IIA (salisbury). Worth every cent imho, and has been used many, many, many times.

MD have closed, so your current options are:
Manual:
ARB
McNamara (air operated locker)
McNamara "spanner" locker (2nd hand only)

Auto:
detroit
lockrite
and probably a few more...

There are a lot of reasonably priced 2nd hand 10-spline ARBs around. However you will probably need to upgrade the axles - at least $500-600.

I personally wouldn't bother with the manual McNamara locker. Unless you only used it occasionally, I am sure it would get very annoying very quickly...

[cmurray]

I personally wouldn't bother with the manual McNamara locker. Unless you only used it occasionally, I am sure it would get very annoying very quickly...
I would disagree. Probably the cheapest option. You should be able to pick one up with the axles that are needed for less than you could buy a 10 spline ARB diff lock, then you need to the compressor to run the ARB! Generally every one that I know that had these would lock them while they were letting their tyres down, and then unlock them at the end of the day when they were pumping their tyres up, this never seemed to cause any issues. I used to leave a 5/8 spanner on my dash, so if I ever got in trouble, I didn't have to go rummaging around in the tool box to get it to lock the diff. They are very simple so there is nothing really to go wrong.

[willvine]

The cheapest way to lock your diff is to weld it up;). But this abviously is not legal and can be scary in the wet.

If you just use it for play and live close to your favorite play ground a welded up diff is great. It only takes a few hours to swap the open diff back when you finish playing. But you have to be keen.



BTW I too am looking for a Mcnamara diff lock for my old truck. let me know if you find 2 of them.

cheers
Will.

[djam1]

Put a detroit in it you have already seen the result it will be the cheapest but you should consider Maxi Axles.

[cmurray]

Put a detroit in it you have already seen the result it will be the cheapest but you should consider Maxi Axles.
Considering you can pick up a bolt diff lock with axles for less than a pair of maxi drive axles, how is a detroit cheaper?



BTW I too am looking for a Mcnamara diff lock for my old truck. let me know if you find 2 of them.

Will where abouts are you? I might know of one for sale.

[series3]

I have seen the detroit locker work, and was amazed with it. two of the same cars, but where one was sliding and losing tractions after about 10 attempts, the other just crawled up there first go.

Do Mcnamara lockers and axles come up often? i would be interested if someone can give me a heads up on a sale.

[series3]

what sort of specs are the appropriate axles for a mcnamara difflock?

[willvine]

Considering you can pick up a bolt diff lock with axles for less than a pair of maxi drive axles, how is a detroit cheaper?


Will where abouts are you? I might know of one for sale.


I am in Sydney.

[djam1]

To quote

cjmurray
Considering you can pick up a bolt diff lock with axles for less than a pair of maxi drive axles, how is a detroit cheaper?

Cj I tried to pick one of these up a couple of years ago Jack Mac laughed at me and no one else communicated

To me it was a lost cause

Duane

[Lost Landy]

Does any one know if the Lockrite diff lock is still being produced? they were quite a good option ive been told for the series Landys.

[Ruski73]

My Series 3 has a McNamara. The bolt action hub is shown in the avatar. I rarely need to use it but when it is locked in the thing is unstoppable. Good luck finding one.

[isuzurover]

To quote

cjmurray
Considering you can pick up a bolt diff lock with axles for less than a pair of maxi drive axles, how is a detroit cheaper?

Cj I tried to pick one of these up a couple of years ago Jack Mac laughed at me and no one else communicated

To me it was a lost cause

Duane

True...

I can only remember seeing 1 for sale in the last 5 years. It was a rover one and something was broken in it.

Even if you could fine one, you could probably get a lockrite for a similar amount.

The salisbury model seems very strong, but if you get a rover one and something breaks...

[navigation2000]

Considering you can pick up a bolt diff lock with axles for less than a pair of maxi drive axles, how is a detroit cheaper?


Will where abouts are you? I might know of one for sale.


I'm interested in acquiring a McNamara bolt type diff lock for the rear of my series 3 ex army.

Question though, I've seen mentioned elsewhere, about "fully" locked, meaning both front and rear diffs. Is this the go?

I can see the advantages of locking the rear on it's own, but is it really necessary to lock the front as well? Fully locked would be pretty awesome I reckon, depending on terrain of course.

Dunno if I'd ever "need" "fully" locked.

Any advices?

[cmurray]

True...
Even if you could fine one, you could probably get a lockrite for a similar amount.

The salisbury model seems very strong, but if you get a rover one and something breaks...
Isuzurover would you seriously recommend someone to put a lockrite in a rover diff? The company that made them even realized how bad this combination was and stopped selling them! All the extra loads of a diff lock without removing any of the weaknesses of a rover diff!

As for something breaking in the rover diff lock, the only thing likely to break is taking teeth of the crown wheel, which shouldn't cause any issues with the diff lock. My brother had an ex-army 2A LWB with 253 V8 and bolt rear diff lock. When he put the 36" Silverstones on it, he started breaking crown wheel and pinions left right and centre, none of these failures resulted in damage to the diff lock. Eventually he put a McNamara hypoid diff in the rear with the same bolt operated diff lock centre and that stopped all those issues.


I'm interested in acquiring a McNamara bolt type diff lock for the rear of my series 3 ex army.

Question though, I've seen mentioned elsewhere, about "fully" locked, meaning both front and rear diffs. Is this the go?

I can see the advantages of locking the rear on it's own, but is it really necessary to lock the front as well? Fully locked would be pretty awesome I reckon, depending on terrain of course.

Dunno if I'd ever "need" "fully" locked.

Any advices?
It's a bugger that you have a Series 3, as I have one to suit a rover diff in a vehicle that I'm no longer using, but your vehicle has a Salisbury, so it's no use. If you want to lock the front diff, you either need an auto locker like a detroit or an air/vacuum operated as they never made the bolt diff lock for the front axle as I don't think it would work as the it was make the uni joint on the axle go out of alignment with the king pins.

Depending on what you are doing will depend on whether you need a front diff lock or not, just a rear diff lock will make a big difference to the vehicles capabilities.

[isuzurover]

Isuzurover would you seriously recommend someone to put a lockrite in a rover diff? The company that made them even realized how bad this combination was and stopped selling them! All the extra loads of a diff lock without removing any of the weaknesses of a rover diff!

As for something breaking in the rover diff lock, the only thing likely to break is taking teeth of the crown wheel, which shouldn't cause any issues with the diff lock. My brother had an ex-army 2A LWB with 253 V8 and bolt rear diff lock. When he put the 36" Silverstones on it, he started breaking crown wheel and pinions left right and centre, none of these failures resulted in damage to the diff lock. Eventually he put a McNamara hypoid diff in the rear with the same bolt operated diff lock centre and that stopped all those issues.
.

What size are the axles/splines in your locker? Does it have a completely new centre? Or just a new cross shaft? 2-pin or 4?

As you yourself stated, in rover 4.7s, the CW&P usually breaks first. I have broken 2 rover 4.7 CW&Ps, but never broken a diff/hemisphere. IMO many diff breakages in SIII and later vehicles are actually caused by the circlip falling out.

Given the above, IF I was using a rover rear in a series, and IF I wanted the cheapest option, I wouldn't have a problem fitting a lockrite.

[cmurray]

What size are the axles/splines in your locker? Does it have a completely new centre? Or just a new cross shaft? 2-pin or 4?

As you yourself stated, in rover 4.7s, the CW&P usually breaks first. I have broken 2 rover 4.7 CW&Ps, but never broken a diff/hemisphere. IMO many diff breakages in SIII and later vehicles are actually caused by the circlip falling out.

Given the above, IF I was using a rover rear in a series, and IF I wanted the cheapest option, I wouldn't have a problem fitting a lockrite.

You've got to be kidding me! A lockrite just replaces the planetary and sun gears in your existing diff carrier! They didn't even replace the cross shaft! So you still have issues of the carrier allowing the crown wheel to flex away from the pinion, which causes teeth to be broken off the crown wheel! Plus all the issues around the cross shaft. Installing into a Salisbury is ok as the standard diff is not really a weak point, but in a rover diff, they do not remove any of the weaknesses in the diff.
I have broken one rover diff, which was in the front of my 90, and the cross shaft ended up in 3 pieces, and I didn't think I was giving it a hard time.
I have seen a rover diff in a 2A shorty let go when the cross shaft in the rear diff snapped in two. I've also seen the actual carrier fail in the rear diff of a late 70's Rangie, it tryed to spit what was left of the planetary gears out of the rear of the housing.
The bolt operated diff lock comes with 24 spline axles and is a 6 gear hemisphere as opposed to the rover 4 gear hemisphere. The one thats fitted to the my old 86" never gave me an issue. I can remember axle tramping my way up a hill in 1st low, no issues at all, I can remember thinking while I was doing it that I was glad I had the diff lock in the back, as without it, the rear diff or an axle would have broken for sure.

[isuzurover]

I agree - A lockrite is the probably the weakest option. But it doesn't make anything weaker than it already is - i.e. you aren't going to be breaking more CW&Ps (may put more stress on the cross shaft). So they may be an option for some - i.e. people with a gentle right foot and standard size tyres - that haven't even broken anything with a standard setup.

A lockrite costs about $300? (from US). A detroit is what - $800? An ARB is about 1.1k and a McNamara (air) is about 2k? If you have a lockrite in a series 4.7 (rover) diff, replacement halfshafts, CW&Ps, and diff cross shafts are dirt cheap. So if you are happy to replace those if/when they break, then that may be an option for some.

The original poster sounded like they wanted a cheap option - as probably do others who have a series and don't want to spend lots of $$$ for a locker. You only have 1 McNamara locker, and by the sounds of it a few takers. It isn't like they are common. However - from what you have said, they sound quite strong - I didn't realise they supplied a whole new casing/hemisphere with the locker.

Personally, I prefer manual lockers (MD/ARB/JM), and wouldn't run an auto locker. But I also wouldn't run a rover rear diff either.

If I had a series shorty that I wanted extra traction for on the cheap, I would modify the axle casing to fit toyota 8" centres, and cut down some toyota 1.3" 30 spline axles to suit. If you wanted to be really cheap, you could even run shimmed toyota LSDs...

[rovercare]

You've got to be kidding me! A lockrite just replaces the planetary and sun gears in your existing diff carrier!.

Have to agree here, the Lockrite merely cams on the original cross shaft:eek:

You'd be a fool to fit one to a rover centre and I've fitted them to a few things

The cross pin nor carrier can handle to punishment of a lunchbox locker

And cross pins break alot, because they snap in half, aswell as missing circlips, flogging pin centres in the carrier and just general crap materials/design

I've probabaly broken more rover centres here than most

[isuzurover]

Have to agree here, the Lockrite merely cams on the original cross shaft:eek:

You'd be a fool to fit one to a rover centre and I've fitted them to a few things

The cross pin nor carrier can handle to punishment of a lunchbox locker

And cross pins break alot, because they snap in half, aswell as missing circlips, flogging pin centres in the carrier and just general crap materials/design

I've probabaly broken more rover centres here than most

Agree 100% - however you have(/had) a lot more HP than most ;)

However, for someone in a series with 50Hp on a GOOD day!, pizza-cutter wheels and a pile of spare diffs and axles (series bits are usually sold for scrap value...)...

[rovercare]

Agree 100% - however you have(/had) a lot more HP than most ;)

However, for someone in a series with 50Hp on a GOOD day!, pizza-cutter wheels and a pile of spare diffs and axles (series bits are usually sold for scrap value...)...

Had:(:(

But I wrecked most in the stockers I bought to wreck:twisted:

Don;t think you could find a lockrite for a rover centre anymore

Jacmc, bolt operated locker is:cool: very retro

Mates old man had one in a 2A 30 years ago, with a 225 slant then 265 hemi:D

[series3]

So, if i do manage to get my hands on a mcnamara bolt-operated diff locker, i should look into some more heavy duty axles to go with it? is the rover centre on the SWB series III up to the challenge?

This is all new to me, having only had the old girl for about six months and just looking into things now.

thanks everyone for your input, its awesome to have this kind of knowledge on tap for a novice

[series3]

It's a bugger that you have a Series 3, as I have one to suit a rover diff in a vehicle that I'm no longer using, but your vehicle has a Salisbury, so it's no use.

would this one your talking about fit a SWB series III?

[isuzurover]

So, if i do manage to get my hands on a mcnamara bolt-operated diff locker, i should look into some more heavy duty axles to go with it? is the rover centre on the SWB series III up to the challenge?

This is all new to me, having only had the old girl for about six months and just looking into things now.

thanks everyone for your input, its awesome to have this kind of knowledge on tap for a novice

If you have a (stock) SWB, then you have a rover diff with 1.1" diameter 10 spline axles. According to cmurray above, the (rover) mcnamara has 1.24" 24-spline axles, which is the same as the later model stuff.

He says he has a rover-type. So it would fit your vehicle.