hey everyone, I recently changed my rear diff fluid and instead of researching the required fluid on my own I trusted the employee at the auto parts store to tell me what fluid to use. I ended up changing the rear diff with regular valvolin 80w-90 fluid instead of the synthetic 75w-90. Is this going to be a proble? 05 TB LS 4x4 with 93K miles on it. Old fluid was pretty dirty and probably had never been changed before. Thanks.