Differentials

dcaven

Well-known member
Nov 16, 2007
78
1
Houston, TX
I recently had a CDL installed on my 2003 Discovery. Now, it is in the shop having Ashcroft ATBs installed both front and rear. Are any of you running this setup? What kind of performance improvement can I expect? I’m hoping it will be significant and am interested in hearing about others experience with the same setup. Thanks.

David
 

RVR OVR

Well-known member
Dec 9, 2004
140
10
IL
I have a Detroit rear locker and a front TruTrac. I am assuming the TruTrac is the same as the Ashcroft ATB in function. Personally, I don't like the Tru Trac front. I had it on two Discoveries and often get caught in wheel up situations where, even with modulating the brakes, the front doesn't lock up as it should. It will be better than open diffs, just not as good as fully locked ones.

In this scenario you see one wheel come up and spin and the other didn't move, even while applying the brake.

That being said, you have a D2 with traction control, so maybe that will help and combined with the ATB get better results.

 
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BDM

Well-known member
May 23, 2005
305
24
OR
I have a Detroit rear locker and a front TruTrac. I am assuming the TruTrac is the same as the Ashcroft ATB in function. Personally, I don't like the Tru Trac front. I had it on two Discoveries and often get caught in wheel up situations where, even with modulating the brakes, the front doesn't lock up as it should. It will be better than open diffs, just not as good as fully locked ones.

In this scenario you see one wheel come up and spin and the other didn't move, even while applying the brake.

That being said, you have a D2 with traction control, so maybe that will help and combined with the ATB get better results.

If that was you, your spotter did a terrible job of putting you on the right line.
 

DEVIANT

Member
Mar 17, 2019
24
1
80111
I recently had a CDL installed on my 2003 Discovery. Now, it is in the shop having Ashcroft ATBs installed both front and rear. Are any of you running this setup? What kind of performance improvement can I expect? I’m hoping it will be significant and am interested in hearing about others experience with the same setup. Thanks.

David
I am running precisely this set-up. Got the third members from Ashcroft (also re-geared for 35x10.5s) and swapped them in. It is worth learning some left foot brake to make wheel spin more predictable (the traction control is a bit "jerky" though it does contribute some). Also make sure to find non-synthetic gear oil WITHOUT the limited slip friction modifier (that is for clutch based limited slip diffs)
 

jymmiejamz

Well-known member
Dec 5, 2004
5,729
170
32
Los Angeles, Ca
It will be a minor improvement in traction but a substantial improvement in durability. The stock carrier is very weak. I have a trutrac in the front of my D90 and it’s about as good as traction control, IMO. Even though I don’t think they’re great, I do think a truetrac/ATB is the best option for front diffs. I’m not a fan of air lockers.
 

K-rover

Well-known member
Jan 15, 2010
2,067
30
Raleigh, NC
It will be a minor improvement in traction but a substantial improvement in durability. The stock carrier is very weak. I have a trutrac in the front of my D90 and it’s about as good as traction control, IMO. Even though I don’t think they’re great, I do think a truetrac/ATB is the best option for front diffs. I’m not a fan of air lockers.
I agree with the TT being an improvement in durability, but Im curious why you don't like air lockers?
They are more complicated than a mechanical locker, but they also have way better road manners. Ive had my Ashcroft air lockers in for about 4yrs now. So far have had zero issues or complaints.
 

Gordo

Well-known member
Ive had both ARB air lockers all the way around and trutrac/Detriot. The Trutrac/Detriot is more reliable/easy as there are no switches/airlines, pumps relays etc to break and is plenty strong in my experience. IN my opinion (mostly mud though) the air lockers make it tough to turn in mud but the traction is better than the trutrac and Ive experienced the same issue with it not locking up when I wanted it too. The airlockers are nice and any lockers do make a nice difference offroad, you will notice it for sure. Like the previous poster said it is great for reliability as the 2 pin 4 spider gear diffs are much stronger. With a detriot Ive have always heard it is best to put HD axles in too as if one breaks it can grenade the detriot. I dont think the tru trac is as sensitive as the detriot. I have HD axles and cvs in my d1. i didnt run them with the ARBs but it was in a series hybrid so it was light and mud is a bit more forgiving than rocks. My current series hybrid has a trutrac up front and a welded rear, rovertracs CV/axles and maxidrive in the rear. That works great too but isnt good on the road (its a trailer queen). It has 37 boggers and no issues with the trutrac (other than not always locking up when I want it too) although Ive heard this size tire is too tall and big for the trutrac to work properly (I think they recommend 32s but with the 235s on the D1 it still doesnt want to lock up when I want it too).
 

jymmiejamz

Well-known member
Dec 5, 2004
5,729
170
32
Los Angeles, Ca
I agree with the TT being an improvement in durability, but Im curious why you don't like air lockers?
They are more complicated than a mechanical locker, but they also have way better road manners. Ive had my Ashcroft air lockers in for about 4yrs now. So far have had zero issues or complaints.
I was about to say I've never had air lockers in a truck, but I forgot I owned a RRC with them back in the day. I can't remember if they worked or not. I feel like ARB lockers are like CB radios. In theory they are great, but in practice they never really work right. Almost every group ride I've been on there is always someone dealing with ARB locker issues, whether it be air leaks, wiring issues, ect.. I love the idea of selectable lockers, but in my opinion they aren't an upgrade over a DL/TT combo.
 

Tugela

Well-known member
May 21, 2007
4,349
177
Seattle
I've been on some pretty marginal terrain in a NAS D90 that had ARB air lockers front and rear. They worked exceptionally well, other than limiting steering. The main drawback I found was the need for frequent button-pushing. Turn the compressor on, lock the rear diff, lock the front diff, unlock the front diff, unlock the rear diff, turn the compressor off, turn the compressor on, etc. Coming from a RRC with an automatic locking center differential, the amount of driver input was notably different.
 

fishEH

Well-known member
Jan 26, 2009
6,879
171
Lake Villa, IL
I've been on some pretty marginal terrain in a NAS D90 that had ARB air lockers front and rear. They worked exceptionally well, other than limiting steering. The main drawback I found was the need for frequent button-pushing. Turn the compressor on, lock the rear diff, lock the front diff, unlock the front diff, unlock the rear diff, turn the compressor off, turn the compressor on, etc. Coming from a RRC with an automatic locking center differential, the amount of driver input was notably different.
That's the benefit of selectable lockers. On when you want them, off when you don't.
I get the value of Detroit/TT and air lockers. Personally I like to get as far as I can without lockers and only kick them on when I get really stuck. I love making it up an obstacle to hear someone say "well he's got lockers" just so I can tell them they weren't engaged.
 

discostew

Well-known member
Sep 14, 2010
5,868
323
Northern Illinois
That's the benefit of selectable lockers. On when you want them, off when you don't.
I get the value of Detroit/TT and air lockers. Personally I like to get as far as I can without lockers and only kick them on when I get really stuck. I love making it up an obstacle to hear someone say "well he's got lockers" just so I can tell them they weren't engaged.
What about the truck you have a Detroit Locker in? You ready to sell that noisy thing to me yet? The locker, not the truck.
I've got a couple ARB lockers I can work into the deal.
 

fishEH

Well-known member
Jan 26, 2009
6,879
171
Lake Villa, IL
What about the truck you have a Detroit Locker in? You ready to sell that noisy thing to me yet? The locker, not the truck.
I've got a couple ARB lockers I can work into the deal.
I have Ashcroft air lockers sitting in buckets ready to roll already. But yeah I'm ready to part with the Detroit and TruTrac. Just haven't found time to yank them out yet.
 

RVR OVR

Well-known member
Dec 9, 2004
140
10
IL
If that was you, your spotter did a terrible job of putting you on the right line.
I was driving. I would love to blame the spotter but I am sure driver and rig had something to do with it.
 

dos531

Member
Feb 1, 2016
9
0
Pasadena, CA
I've never personally run a truetrac style diff as I prefer the engagement of an air locker, but ive wheeled with others that have them. Around the campfire they sound great. They lock up as soon as you touch the brake! No air lines to worry about! In reality it never seems to work out that way. Ive seen more of them acting like an open diff when you really need them. If I was going through all the trouble of installing new diffs I would only go air locker. I run TRE air lockers on 2 of my rigs and have been really happy with them especially for the price.
 

rover rob

Well-known member
Mar 29, 2016
151
9
upstate NY
my parts truck came with a older kam dif air locker and shafts. on that locker there is a handle mounted on it so you can manually lock/unlock it if anything in the system breaks.
 

discostew

Well-known member
Sep 14, 2010
5,868
323
Northern Illinois
I want to run a Detroit locker in the rear. I love those things. Everybody thinks your diffs going to blow up with all that noise on decel turning. I hear that and know exactly what it is. People always complained about that shit.