Amsoil in differential = no LSD...

[Gary - K7GLD]

I'm sorry to report (about $40 worth!), that after about 500 miles on the truck after switching to Amsoil 75/140 in my LSD differential due to frequent towing applications (no friction modifier was added). I now find my LS function is not working...



Prior to the switch, I experienced occasional "chirping" of the inside tire over loose or irregular surfaces when turning sharply - and more noticeable when both tires were on loose surfaces - I had been suspicious when that tendency disappeared after the lube switch. But today tried placing one rear wheel on a grassy, muddy area, and the other on a solid dirt road, and it just sat there spinning the wheel on the muddy surface...



(sigh!)



Guess I'll hafta drain it out (thank God for the drain plug I installed in the differential cover!), and try replacing it with the equivelent dino product... And yes, I did all "figure 8's" and recommended stuff...



We all learn - some of us just learn SLOWER than others...

 

[DOWG]

Don't drain the Amsoil; it is a good product. However, the Amsoil claim "you don't need the friction modifier with Amsoil" was not true with my truck. Add the modifier and you will be OK.

 

[Gary - K7GLD]

It's MY understanding - someone correct me if I'm wrong - that the modifier is to reduce "chatter" because MORE "slipperyness" is needed - not LESS...



Adding friction modifier NOW would only make the problem WORSE!

 

[Pit Bull]

Originally posted by Gary - KJ6Q



Adding friction modifier NOW would only make the problem WORSE!

That is true. You must have a real loose LSD Sorry to hear this, I won't be changing mine for another 40K miles but will go with Mobil 1 75W90 like I did on my 2000. Nothing agains't Amsoil just like Mobil 1, since it worked well for me in the past.

 

[Gary - K7GLD]

DUNNO - as mentioned above, the LSD was apparently operating fine with the original stock stuff - just the right amount of "grab" to suit me... I guess the Amsoil is simply TOO good in this particular application - tho' I'm sure we've both seen wildly varying results where clutches and LS units are concerned - not too predictable, what works in one situation, fails miserably in another... same with manual trannies - a good synthetic in ONE shifts great - and makes the next one grind like mad...

 

[LSMITH]

Put in some Mobil 1, no need to go back to dino oil.

 

[Gary - K7GLD]

I'd really LIKE to stick with synthetic - but ya get sorta gun-shy after a couple of failed attempts - and this stuff ain't cheap...

 

[tarussell]

Years ago Ford Motor Co. offered an additive that actually helped the clutches grip instead of slip. I don't know if they still offer it and I don't have a part # to back this up but we use to use it to help slipping torque converter clutches last a little bit longer. The stuff really worked well and it sounds like it would bennefit you too. Ford does sell the additive that makes things slip as well so becareful.

If I can locate an old part # I will post it , but I doubt that I will be able to dig one up, sorry. HTH , Thomas

 

[Gary - K7GLD]

Thanks Thomas - I'd be willing to give it a try if you are able to come up with a part # - but don't knock yourself out over it - if all else fails, and Mobil 1 DOES make a proper differential lube in the 75w/140, I might as well toss in a few more bucks and give that a try...



After all, what's "a few dollars more" at this point...

 

[Extreme1]

Or, you could "adjust" the LSD...

If you look at the plate layout in the FSM, they expect you to line up the plates in an order that limits the number of clutch/plate connections. If you pop out the carrier, dissassemble the case and re-order the position of the clutches and plates, the diff will get much "tighter".



I have no idea why (or when) DC did this change but the FSM for my '94 shows the "correct" clutch/plate assembly order. The LSD I got from Okie-go was assembled this way and that is the way spec'ed in the newer FSM.



Mine was loose after I installed it with Amsoil but tightened up after a few hundred miles (no 8's) and I added 1 oz of modifier to stop the chattering.

 

[TowPro]

Gary, don't switch it yet. First the Dodge "limited slip" is just that "limited". On my new 2002 the Limited slip works if both wheels are in the snow/mud, but put one on the snow, and one on black top and the snow side will spin, "BUT" the clutches are working, and the truck will still move forward.



I recall about a year ago somebody posted Dodge's test for the Limited slip rear. IT was something like put the truck on a lift, have a person hold one side, while you put a torque wrench on the other side. turn the torque wrench, if the wheel turns with less then 35 lbs, there is a problem. I can't remember if 35 was the exact mesurement, but what ever it was it seemed very low.



These rears are not "locking diferental" rears, the have to allow slip, but on "almost" equel traction conditions, they will turn both wheels.



I had a ford with a LSD rear in it a couple years ago. I got stuck and it spun posi, for about 30 seconds, then heated up and became an open rear.

 

[BillGotthelf]

Tried Castrol 75-90 synthetic in my 96 without any additives. It worked as well as the stuff Dodge put in from the factory. Now both my 99 and 96 have Amsoil 75-90 in the rears and in the front on my 96. Lots of dirt roads here and when I get on it I get two rooster tails out the back. Thats after 130,000 and 89,000 miles-no problems here.

 

[Got Smoke?]

Thanks for saving me $40 I was getting ready to go Amsoil in the rear because my limited slip is starting to not work so good!

 

[John Berger]

Gary, I haven't noticed any problem with mine and I haven't had the modifier in since I drained the stock lube out 68000 miles ago. I'm using Amsoil Series 2000 75W-140. Maybe I just haven't been in a situation where I can truly tell whether it's working or not.

 

[Gary - K7GLD]

Thanks for the helpful comments and suggestions above - as to the one suggestion about dissassembling the differential and re-arranging clutch plates - thanks, but no thanks!



The LS seemed to be working fine before the lube change - clear evidence it was functioning - and none since the lube change - I feel the Amsoil is an excellent lubricant, just TOO slippery to be compatible with my specific LS clutches - so, I'll have to try another lube for compatibility, and I still prefer to use an appropriate synthetic since I frequently tow a trailer in Sierra grades.



On the other hand, it WOULD be helpful to know exactly WHAT the DC recommended torque is for proper LS action - and John, you're probably in the same boat I was, and won't really know if your LS is operating properly or not until it's tested under the right circumstances - and I'm not sure MY test was reasonable and proper either - but sure expected more definite traction than what I got - there was absolutely NO signs of spinning of the tire on the packed dirt surface, while the one un the muddy surface spun rather freely...



One approach I'm sorta considering, is using about 1 quart of the Amsoil with an added 3 quarts of equivelant dino lube for a "blend" of synthetic/dino lube - the higher percentage of dino lube MIGHT provide the additional "grip" I want, while the 25% of Amsoil substitutes for the Friction Modifier that would otherwise be needed - and give at least SOME of the benefits of the synthetic... At least that way, I can salvage use of the Amsoil...



Any thoughts?

 

[Extreme1]

Originally posted by Gary - KJ6Q

... as to the one suggestion about dissassembling the differential and re-arranging clutch plates - thanks, but no thanks!

Awww, come on Gary! (It really isn't hard and there are no special tools required. ) Peel open that nice new truck and dive in!!



Oo. Oo. Oo.



As for the mix, you sure could do that. An alternative would be to buy the DC branded lube (assuming that really is what was in there to start with), and mix the Amsoil with it so you would still be 100% synthetic...

 

[BillGotthelf]

Gary before you do that Parts houses do sell pint bottles of friction modifier for LS rear ends.

 

[Gary - K7GLD]

Bill - the "friction modifier" sold for LS differentials is to make the lube MORE slippery, to stop the LS clutches from GRABBING - MY problem is that the Amsoil is ALREADY too slick - adding additive would only make the current problem WORSE...



BUT anyway, the problem is solved - covered in a new thread...

 

[jwinnie]

Gary,



I am having the exact same problem after switching to Valvoline semi synthetic 85/140. The loss of grabbiness in the diff is very noticeable, I also did NOT add friction modifier.



Do you think the higher viscosity (85/140 vs. 80/90) could be the problem?? (I know I'm reaching but it never hurts to ask right?) What do you think?



I might try Mobil 1, 75/90 at my next change.

Just my . 02,



John

 

[Gary - K7GLD]

Golly John this LSD clutch stuff really baffles me!



As I posted in the other LSD thread, these LSD clutches seem to each have a mind of their own when it comes to lubes and proper operation! My LSD seems to be working properly once again WITH the very same lube YOU are having problems with - just as many guys get operation they are happy with using the same Amsoil *I* had problems with - go figure!



I know I would vastly prefer to run with the Amsoil, but because of the way I use my truck, and the places we go, I occasionally really need my LS to work properly...



Sorry I have nothing better to offer you...