I just got all my drivetrain fluids replaced about a month ago, I went and got in the car a week or so ago after that and notice that I hear a binding noise when making a turn from a stop. I just had the fluid replaced and they drained my diff and then told me that they were out of the regular fluid and only had synthetic, and they said it wouldnt hurt it. I have heard that its not good for some cars and the brass parts in the trans. and other things. I just want to know whats going on? why my car is not acting like it should? I have a bone stock rx7 with 60k so what happend? thanks in advance for your time!

 

Pretty normal. Changing the fluid helps it work better. It will probably lockup a bit faster now.

 

I hope they put the right oil in there. Do you have a receipt that states the oil they used?

Synthetic is fine so long as the viscosity is correct and the oil can be used in an LSD.

 

Any GL-5 oil is fine for the diff. 75w-90 is probably the best all-around viscosity.

The suggestion about brass pertains to the fluid you use in the transmission. I personally use true GL-4 synthetics like Amsoil MTG or Redline MT-90. That way you get GL-4 friction characteristics and chemical friendliness but you get the benefits of synthetic.

Bottom line, you should find out exactly what fluid they used.

 

Thanks guys! I am working on finding out what they used it was a mobil one product but im not sure the viscosity... Just makes me mad that it was drained before they figured out that they were out of the standard fluid.

 

I was told this could be a bearing? sound right? also if their is a problem i was consdering the 2 way mazdaspeed lsd for 900 any thoughts?

 

The stock FD diff is a Torsen, which relies on friction of worm gears to work as a limited slip. If they put in something not GL5 (for instance, a gear lube intended to improve synchro action in the trans), the friction characteristics may be totally wrong, causing the chattering/binding.

 

Thanks Dave that seems to be a good thought... Saying its the wrong fluid what should i do? just drain it out and fill it up? or take it apart?

 

I'd just drain & refill with a good synthetic 75W90 GL5. Amsoil, NEO, Valvoline and others make good GL5 lubes.

IMO, it's usually more difficult to get the "best" lube for the tranny, because lube that has the wrong viscosity/friction characteristics cause difficulties in shifting. Most of the GL5 synthetics work well in the diff.

If you still have trouble after the switch, then I'd start to worry, and maybe take it apart.