Friction modifier in XT-M5-QS?

[jabba]

After having the dealer do some tranny work, whatever fluid they replaced in there made the LSD groan like an old man returning soup at a deli. As well, shifts were initially a little tougher, but have eased up. The thing is, the car never did this before the fluid was changed.

Being fed up, I'm getting some XT-M5-QS, but here is the question for those who use it: do you use it straight, or do you add a bit of friction modifier (e.g. XL-3)?

I've read the friction modifier debate, but also read that some dealers actually add a bit of modifier for those who complain about the noise (as directed by Mazda, apparently). And as we all know, dealers are never wrong...

So the question is: after adding the new fluid, if I still get some noise, should I add some modifier until it goes away?

 

[khoney]

Most haven't had the noise since switching over (myself included). Why worry unless it happens? If mine started up again, I probably wouldn't add any modifier based on what I've read on this forum.

 

[CnoTataymo]

I changed to XT-M5-QS last month. It's quieter than the Redline MT-90 by a lot but the LSD whine slightly still there. I didn't add any modifier either an I'm just going to keep it as is.

 

[BigDaddyMS3]

Lsd

I changed my diff oil over to the secret sauce made by Motorcraft. The LSD noise has quieted down a bit after 1K miles. I wont be adding a friction modifier as my race mechanic says it may mess up the synchros.