How do I confirm LSD is working?

[MojaveJoe]

I ordered a Limited Slip Differential on my new truck, and supposedly got one.



But, when one rear wheel is off the road in the mud and the other is on the road (in 2WD), there is lots of spin on the mud side only (from a dead stop).



How do I test to be sure my LSD is working properly?



Thanks in advance for your advice.



Regards,

Joe

 

[XcumminsX]

hit the brakes and the gas at the same time... That should kick it in

 

[Vaughn MacKenzie]

Instructions

1. Do burnout on dry pavement.

2. Count the stripes.

3. If 2 stripes you have LSD.

4. If 1 stripe you're a 1-legger.

5. If 0 stripes check truck for Ford badge

6. If you have more than 4 stripes, put the beer down and call a cabbie



Vaughn

 

[Casey Balvert]

ROFLMAO!!!!

 

[PJereb]

Soneone allready posted a lengthy explination on how to check. If you want to check out the whole thread use the search function. Your truck does not have a Limited Slip Differential, it has a torque biasing differential, no clutches, it works by F. M. I put a picture below from Quafe, which is a huge builder of the torque biasing differentials, so it should be similar to your AAM model. The good things about them are that there are no clutches to wear out, and since they don't have clutches, they don't make a bunch of heat to cook your rear end during excessive wheel spin...



Below is the info from Rhwedges post, hopefully he does not mind me stealing his wisdom





Here it is, a quote from Rhwedges.





"The following is a S. T. A. R. Center Case Report:

Report created Jan 6 2004

Updated Jan 13 2004

STAR Group: Trans Core

Created by: G. Knapp

Customer says his trac-rite rear diff is not working?

GCK1: 01/06/2004

Recommendation/Solution

Review AAM Trac-rite diff characteristics. Rear diff is working or truck wouldn't move. It will overrun like standard diff if operating on extreme differernces in surfaces. (Ice under one rear tire with other tire on dry pavement. ) No further action.

:GCKI:01/06/2004

The 2003 heavey-duty Ram uses and American Axle helical differential or Trac-Rite. The Trac_Rite differential is different then Trac-Lok in that it uses helical gears (Trac-Lok uses clutches) to transfer power to the opposite wheel when slippage occurs. The transfer of power from wheel to wheel is torque sensitive and must have both wheels spinning (not stationary) to function. It is possible for the Trac-Rite differential to not send power to a wheel if is not spinning. Example: Accelerating from as stop and one wheel is on ice and the other on dry pavement. If accelerating to fast, the wheel on the ice may spinand never send power to the whell on the pavement side. A slower start may be necessary to start the vehicles momentum.

A written test procedure for Trac-Rite is not listed in the repair manual and the following points should be noted:

Testing the Trac-Rite differential while the vehicla is lifted and turning one wheel by hand, the opposite wheel will turn in the opposite direction. This is normal.

If the Trac-Rite assembly has and internal failure it will lock axles 100% side to side.

To test the Trac-Rite process, raise vehicle on appropriate lift, place into gear and accelerate quickly (hard launch). A second technician will witness both wheels turning at the same speed at the start of the acceleration.

Another test for Trac-Rite is to slowly drive vehicle in an open area and completely turn wheels to one direction and accelerate hard. . The vehicle will experience tire hop or shudder. This is normal. Trac-Rite differentials do not require friction modifier and should be used only with SAE75W-90 GL-5 synthetic fluid PN 05102232AA.

The Trac-Rite differential found in the American Axles may look like the helical gears have ground away the case. Six small half circles are noticable on the side of the differential opposite of the ring gear. These openings are desinged for oil flow and are not the result of the helical gears grinding through the differential. Please do not replace the differential case or any other part of the axle due to these openings.

Note: All American Axles require Mopar lube part# 05102232AA synthetic and does not use a friction modifier.

RAB40: 01/13/2004



DUH!!

Maybe I wanted a Trac-Lok cause this doesnt sound to good to me when I wanted something to improve traction when one wheel was beginning to spin"







#ad

 

[Bill Stockard]

Re: Instructions

Originally posted by Vaughn MacKenzie

1. Do burnout on dry pavement.

2. Count the stripes.

3. If 2 stripes you have LSD.

4. If 1 stripe you're a 1-legger.

5. If 0 stripes check truck for Ford badge

6. If you have more than 4 stripes, put the beer down and call a cabbie



Vaughn

:-laf :-laf :-laf :-laf



Bill

 

[TheWolf]

Thanks for the post PJereb.



this describes exactly what I have been experiencing! I have appt to have lsd looked at by dealer because it didn't seem to be working very well. They ordered the whole cage thing for the rear so it will be in stock if they have to replace it. Appt is next week.



After your post it seems as though it may be working perfectly! PERFECTLY USELESS!!!! that is. I can't get out of my yard/driveway without using 4 wheel drive. And the driveway is about as flat as you can get , just a very very slight rise where I park. When I try pulling out on the main road ( small incline of one paved road to another paved road)there is snow and slippy stuff during the winter , the other morning I was trying to pull onto the main road and just sat there and spun and spUN and SPUN . Why is my drivers side rear not kicking in and helping out(it is on dry pavement) , thought it might not be working right. Had to use 4 wheel drive to pull onto the road also. Could be a little scary if you let out the clutch( and I tried being gentle also and it didn't work) and you do not go anywhere, it might let you in a position you do not want to be in. Say I started to pull out onto the road and just sat there spinning while someone else is heading right for me?



Now this makes me a little worried because I wanted traction to get out of the yard without having to run in 4 wheel drive constantly. NOT ONLY DO I THINK THAT THIS IS UNSAFE, BUT TRULY EMBARASSING TO HAVE A 4 WHEEL DRIVE TRUCK THAT GETS STUCK ON FLAT GROUND!!!!!:{



This has even happened to me in 4 wheel drive!(this is origionally what started me thinking that something was wrong). Part of the driveway is a little incline then levels off, when pulling into the driveway one day around christmas time half was snow/ice covered the other was dry(the incline is paved). Snow/ice on the right side dry on the left side. So I thought I would just see if the truck would idle up the driveway. Made it about half way up and started spinning, so backed down and tried little faster. Didn't make it . So I stopped right there and tried starting from there to see why my drivers rear tire was not spinning and pulling me up(It is on dry pavement) When I let lthe clutch out it was like I had it in reverse. A backwards I did go! So I thought i would pull up and stop in the middle and use 4 wheel drive( Just like it would happen in any normal snowy day following someone that couldn't make it up any hill. You would have to start from a stop and continue on. especially if someone else was behind you) So I put it in 4 wheel drive let out the clutch and off I go... . BACKWARDS in 4 wheel drive( doesn't sound pretty. ) The passengers side wheels spinning and the drivers side just rolling backwarks fighting thegears as they want to go forward. I guess from the way it sounds that the LSD is working 'exactly' as it is supposed to (as described in the above post)









Sorry for the long post, but once I got started it kept coming out. How would you like to be stuck on pavement when two wheels are on dry pavement?



Anyone else experience the way thaat these Lsd are 'SUPPOSED" to work?

 

[PJereb]

Don't thank me,

Send a PM to Rhwedges, he is the one that I quoted all that from.



Save up for a air locker

Peter

 

[rbattelle]

Remember, the torque multiplier isn't going to work if there isn't enough torque there to multiply in the 1st place. Try applying some brake when you're slipping 1 wheel... that should help.

 

[TheWolf]

I tried some brake and it didn't work.

 

[CRumsey]

I have hesitated to write anything on previous posts that have come up about the AAM LSD but I can't stand it any longer. Out of all the good things I could say about this truck the trac-rite is not one of them. My old 1992 with the Dana LSD was a wonder to behold. I was completely impressed with it and quite often suprised that I did not need the four wheel drive. The situations that truck would go up over and through without shifting into four wheel drive were truly amazing at times. But this truck is a real drag in that department. To think that I was looking forward to the AAM trac-loc and to see the complete dissapoint it has been is upsetting to say the least. That it is a good thing all I need to do is pull the floor shifter to get four wheel drive is small consolation when I need to get going on flat roads while one tire is on dry pavement, is just plain wrong.



Trac-rite = Trac-wrong, the engineer who came up with this abomination that is merely a substitue for one wheel drive is or aught to be completely ashamed of himself. That a company installs it and charges extra for it is also bad business. When I paid extra for the LSD I expected LSD not a fancy name for a concept that can't pull itself off of an icey patch, going downhill, with one side on dry ground.



I am not trying to inflame any nerves or tick anyone off it's just the facts. A LSD should tell when a wheel is slipping and send power to the other side or the side with the best traction or at the very least to both sides when one slips. But this system is designed to send the power to the wheel that has the maximum slippage occuring. That means you are hard pressed to tell the difference between TRAC-RITE and the old style differential on any vehicle with rear wheel drive built in the last 90 years.



IMHO give me a break AAM and DC



Oh by the way; when I complained about the Trac-rite not working in my truck the dealer said and I quote "These trucks have everything controlled by the computer now days and some things are just not as good as they used to be" I guess it was good for a laugh!

 

[RobbieH]

The TracRite is the same concept as the Torsen and Detroit TruTrac. These units have been used in tons of vehicles, and the owners like them for the most part. Hell H1 Hummers had them stock.



There are times they will require user interaction. As was stated above, since they act as a torque multiplier, if one wheel can't get traction at all, multiplying 0 gets 0. You will need to use the brake, or what I've done is slightly apply the emergency brake.



I find them quite useless for offroading my Jeep since when you have a tire in the air they don't do squat, but I do wish my truck had one. I think they are an improvement over the clutch type, since you don't have to worry about what fluid you use and you don't have to worry about replacing clutches.

 

[R.M.THOMPSON]

Try giving "randy's ring and pinion" a call when you get straight with the dealer. They may have or know of a b. o. m. b. for this problem. Word has it that they will have a aam lsd available for the front 9 1/4 soon. Not that anyone wants to hear that right now,but my point is Randy's has got a reputation to uphold and selling products that don't perform is'nt one of them. Please post your comments after/or if you give them a call. I've always gained a lot of insight and tips after talking to their tech's ! Sincerely Mark T.

 

[TheWolf]

easy to say with an auto,but how many feet do you need to drive a manual??? using all of this braking /gas/ brake /stall the engine type of driving to get going when one or even two tires are on dry pavement is BULL!!!!!!!! I paid extra for lsd so I wouldn;t have to use 4 wheel drive to get out of the drive way or where ever else I may be. I may as well saved that money and put it else where because I shift in and out of 4 wheel drive so often it is rediculous. THe knob is going to be worn out soon. I do not care what kind of other vehicles it has been in because right now I think it is a very poor design! That's all I am going to say right now. I am not happy with the lsd as of the moment.

 

[Punkineater]

It's a limited slip guys. You want it active all the time buy a Detroit locker. The old clutch pack style engaged easier because of said clutchpacks which, when new, had some semblance of friction already there. The problem with clutchpack's is that they wear out and unless replaced turn useless in time. This new design actually requires a bit of torque to bind the helical gears and thus lock the differential. The plus side of this differential is that there are no clutch packs to wear out. I have owned the Detroit True Trac which is similar in design and it works great off road, but exhibits the same mannerisms as this new differential in snow. I have the new limited slip in my truck and expected this behavior so it's no surprise. Personally I would rather have this design than clutch packs which, when running big tires, goes south before 50k. Besides, you bought a 4 wheel drive... ... what's the big deal with using it when needed.

 

[Casey Balvert]

Originally posted by mojaveJoe

I ordered a Limited Slip Differential on my new truck, and supposedly got one.



But, when one rear wheel is off the road in the mud and the other is on the road (in 2WD), there is lots of spin on the mud side only (from a dead stop).



How do I test to be sure my LSD is working properly?



Thanks in advance for your advice.



Regards,

Joe

Joe, did you change the oil in your axle? What did you use? Reason I ask is, most of the lube out there has friction modifiers in it and perhaps that is causing the excessive slipping of these axles. Since they have brake shoes to lock the axles, perhaps the additives are detrimental to proper operation. I had to do some searching to find an aftermarket fluid without the additive. Going with the Redline product 75W140NS in mine.



FWIW. Casey

 

[Pug59]

I have LSD on my 03 and thought it was working fine. I got it in the snow and had both rear tires spinning. Pulled it onto an icy driveway and with the truck still rolling forward, it was spinning both tires. I stopped for a moment, when I gave it some pedal, only one tire was spinning. I did not read the thread that said to try applying a light brake to lock it again. I started surfing the web to find information on the new axles. I liked the Dana's in the old truck. While searching I found that the propaganda from AA list it as being "Compatible with ABS, traction control and vehicle stability systems". I remember the salesman giving me the pitch that these trucks have a new type of anti-lock brakes that makes it more stable. Wonder if this is the reason behind the new axle selection.

 

[JHardwick]

Originally posted by rbattelle

Remember, the torque multiplier isn't going to work if there isn't enough torque there to multiply in the 1st place. Try applying some brake when you're slipping 1 wheel... that should help.

I tried the e-brake trick, all I got was the imfamous wheel hop from this soft riding slug. I do however think I have a solution ... ... ... ... . but should I have to?

 

[GBrzezinski]

Are you guys running empty when having tracktion problems? I've been running all winter with 1500# in rear. No problems with my rear not locking. Hate these tires though (DRW)

 

[TheWolf]

the post on the first page explaines it all. Before it was posted I had an appt with dealer to find out what is wrong. I took the post in with me when I went because they have had several people in there questioning about it. They looked for shavings in the rear end and checked it out, didn't find anything( didn't think they would after reading the post on the first page). I got a free rear oil change anyway. Nothing was changed, but again it seems nothing was wrong to begin with.