Differential additive - why?

I recently was able to get my hands on the maintenance history of my truck (I purchased it with 85k miles). At 77k miles, a Toyota dealer added differential additive and I’m trying to understand why. Is the only reason to use additive to reduce chatter if it shows up? My local dealer said they don’t recommend changing the differential fluid ever, yet this other dealer used additive…which seems like conflicting messages. It’s not really lifetime if additive needs to be put in there. Wouldn’t it be better to do a complete flush?

 

Dealers are crooks, they will sell a fridge to an eskimo, if the Eskimo don’t know better.

 

Agree with ^ but the notion you should never change the diff oil is also completely illogical considering cost to service versus cost to repair/replace. I’m sure you could go a good long while on the stock fill but there comes a point where you should clean / check the magnet and make sure you don’t have any water intrusion - not to mention freshen the oil.

If you can lay on the ground and loosen/torque a bolt you are capable of draining and filling the diff. Get some new washers from your local dealer parts counter for the drain and fill bolts and 4 qts of your favorite 75-90 gear oil spend 10 minutes watching YouTube and you’re all set. When you see how gross the oil draining is you’ll be glad you aren’t keeping it in there “forever”.

 

It’s 30-50k service, 50k if I use synthetic

 

You need a new dealer !

 

Maybe the previous owner put in an lsd. My dealer put in additive for me because I had an lsd.

 

When I had it done at the dealer my receipt said "blinker fluid." But it didn't specify a manufacturer or weight. Makes me sooooo mad. I don't even know if they actually did the work. Why would they use blinker fluid when I requested a differential oil change???

Life is hard.

 

Take fill plug out before you take out drain plug, always want to be sure you can fill before you drain anything.

 

All it says is "LTD Slip Additive". I don't know what they put in.

The truck was basically stock when I got it. Considering it was a 4.6 and stock, I would be surprised if it had an LSD installed. How would I know if an after-market LSD was installed?

 

It would be clearly labeled on the diff.

 

I think you can still check this way.

Raise the rear axle to put both rears tires off the ground. Spin one. If they spin the same way, you have an lsd. If they spin opposite directions, open diff.

 

Thank you all. Very helpful!