Detroit locker

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Chalky.

Chalky.

Well-Known Member
Posts
5,150
Location
Mid Wales
Hi all!

I'm thinking of taking out the Ashcroft atb from my rear diff and installing it in the front.
With the 90 being relagated to purely a second, fun vehicle I'm not so concerned with the few quirks that a full locker in the rear gives when 'unlocking' around corners on the road, and with the sort of thing I'm doing and want to do in the future, I could really use the extra benefits a full locker provides. I'm not kean on airlockers with the associated costs.

My main question is who has one, how do you find driving it in a swb, and where did you buy from. Also after sales any good? Thanks in advance!
 
I had a 90 on 36" tires which had a Detroit locker in the rear and a limited slip in the front it was a great set up off road and I had no problem on the road with it. I broke a half shaft and drove it home and it damaged the internal rings on the locker and I haven't been able to get replacements for them so after sale is not so good. I would love to get another one to put in it.
 
Turboman said:
Yes.

I liked it, very good when it was greasy off road.

It isn't a problem on the road if you have an LSD in the front axle, which I did.
Click to expand...

Thanks Turbo, that will be my set up also as I'll move my atb into the front axle! Was yours in your 90 or a longer wheelbase vehicle? Can you remember who/which company you bought it through? Paddocks seem the most well known that I've recently come across!

Here's to a potentially early Christmas present to myself!! :)
 
I had one in a three quarter ton GMC 4x4 and didn't really like it. I wouldn't put one in my vehicle. There is a very good YouTube video where a knowledgeable fellow discusses all lockers and I think he prefers the TrueTrac over all the others.
 
Gord Wedman said:
I had one in a three quarter ton GMC 4x4 and didn't really like it. I wouldn't put one in my vehicle. There is a very good YouTube video where a knowledgeable fellow discusses all lockers and I think he prefers the TrueTrac over all the others.
Click to expand...

In what way didn't you like it mate? Did you install it yourself and adjust the backlash to what the original felt like?

The Ashcroft atb acts very similar to the true trac, its not a proper locker though, more like an lsd. I'll put this upfront. I kind of want/need a full locker in the rear, and its too expensive for me at the moment!
 
Gottschalk said:
Thanks Turbo, that will be my set up also as I'll move my atb into the front axle! Was yours in your 90 or a longer wheelbase vehicle? Can you remember who/which company you bought it through? Paddocks seem the most well known that I've recently come across!

Here's to a potentially early Christmas present to myself!! :)
Click to expand...
It was in a 2.5TD Ninety. So not a lot of power, which I think helps with issues on the road as well. The locker unlocks when you lift your foot off the throttle, so if it doesn't unlock on corners, slowing down will help.

As has been commented, the one problem with Detroit Locker is sales and parts in the UK. They are now made by a US company called Eaton Transmissions, and I don't know who their agents in the UK are. I bought mine off a company called Crown Diffs, a chap called Steve. He was very helpful, and sold the lockers, and the parts. He would also build them up, either on your own diff, or on another unit.
Sadly, as far as I know, he stopped trading a few years ago.
So Google Search and asking around would be my only suggestions now.

You really will not regret getting locking diffs. They should have been fitted as standard, or at least as a factory option.
When I fitted them, I found I could drive over the greasiest surfaces without even putting my fag down.
No wheelspin, no axle tramp, very little sideslip. Result.
 
Gord Wedman said:
I had one in a three quarter ton GMC 4x4 and didn't really like it. I wouldn't put one in my vehicle. There is a very good YouTube video where a knowledgeable fellow discusses all lockers and I think he prefers the TrueTrac over all the others.
Click to expand...
Tru Trac is a limited slip differential, very good for the front axle, and in the rear for the occasional off roader.
For vehicles that will be used off road more than on the road, a full locker in the rear is vastly superior.
 
The Detroit came in the truck. To be sure we are talking about the same thing I will try to describe how it worked. On each side of the diff there is a pair of dog clutches held together by strong springs. These clutches have ramps leading up to each cog. When you go around a corner the outside wheel which is rotating faster causes one of the clutches to ride up the ramp thus allowing extra motion for that wheel. This riding up the ramp repeats multiple times with much clattering and jerking of the rear end. It was a bit unnerving. I think it was tricky to drive around corners in snow. I seem recall that some of this could be avoided if you coasted around the corner rather than accelerate but not sure as this was 40 years ago. Maybe the springs in the clutches could be changed? I just think it is a bit too much for use on the street.
 
Gord Wedman said:
The Detroit came in the truck. To be sure we are talking about the same thing I will try to describe how it worked. On each side of the diff there is a pair of dog clutches held together by strong springs. These clutches have ramps leading up to each cog. When you go around a corner the outside wheel which is rotating faster causes one of the clutches to ride up the ramp thus allowing extra motion for that wheel. This riding up the ramp repeats multiple times with much clattering and jerking of the rear end. It was a bit unnerving. I think it was tricky to drive around corners in snow. I seem recall that some of this could be avoided if you coasted around the corner rather than accelerate but not sure as this was 40 years ago. Maybe the springs in the clutches could be changed? I just think it is a bit too much for use on the street.
Click to expand...

Yeah definitely the same thing! I know Dave Ashcroft from ashcroft transmissions, back in the day, helped to re-design the 'ramp' part so they were smoother and reshaped so as to eliminate the snap and banging somewhat of the unlocking, however, before it could be implemented they were taken over (I think by Eaton I'm not 100% sure) and they stuck with the original design. Unfortunately.

I better give it some more thought, I do still drive a fair bit on the road so perhaps another atb upfront as suggested to me before would be a sufficient compromise. Thanks for your helpful replies! :)
 
Gord Wedman said:
The Detroit came in the truck. To be sure we are talking about the same thing I will try to describe how it worked. On each side of the diff there is a pair of dog clutches held together by strong springs. These clutches have ramps leading up to each cog. When you go around a corner the outside wheel which is rotating faster causes one of the clutches to ride up the ramp thus allowing extra motion for that wheel. This riding up the ramp repeats multiple times with much clattering and jerking of the rear end. It was a bit unnerving. I think it was tricky to drive around corners in snow. I seem recall that some of this could be avoided if you coasted around the corner rather than accelerate but not sure as this was 40 years ago. Maybe the springs in the clutches could be changed? I just think it is a bit too much for use on the street.
Click to expand...

The later ones are less harsh, they are known as soft lockers, and have some steel bushes inside replaced with polyurethane.

Gord Wedman said:
Glad to help out. The way I look at it you are always going to find a place that stops you, like Mt. Everest, so why go overboard.
Click to expand...

I have never been to BC, but I have been to Eastern Canada, and it is a bit different to the UK. Over here, dirt roads, ice, and rocks are not that common. What is common is clay soils, and lots and lots of rain, which results is surfaces that are extremely greasy. So often you may not make progress even over a moderately sloping field, let alone Mount Everest.
 
Gord Wedman said:
The Detroit came in the truck. To be sure we are talking about the same thing I will try to describe how it worked. On each side of the diff there is a pair of dog clutches held together by strong springs. These clutches have ramps leading up to each cog. When you go around a corner the outside wheel which is rotating faster causes one of the clutches to ride up the ramp thus allowing extra motion for that wheel. This riding up the ramp repeats multiple times with much clattering and jerking of the rear end. It was a bit unnerving. I think it was tricky to drive around corners in snow. I seem recall that some of this could be avoided if you coasted around the corner rather than accelerate but not sure as this was 40 years ago. Maybe the springs in the clutches could be changed? I just think it is a bit too much for use on the street.
Click to expand...

It isn't. I drove thousands of miles on tarmac using the Detroit locker rear, Tru Trac front combination, with no issues at all, except maybe the steering being a bit heavier.
A Ninety is fairly light compared to a GMC truck, and has a fraction the power. In addition, it is rare to get ice on roads in the UK.
And the later soft lockers are more suited to road use.
 
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