Anyone try Royal Purple tranny & diff fluids?

[bfd]

Its about time to change the tranny and diff fluids on my 1990 535i, 5spd, 101K miles. I currently have Redline in the car with a little over 30K on it. So, has anyone tried Purple Royal Synchomax tranny or MaxGear diff fluids? Any good?

I'm asking cuz my local auto parts store will sell me the Synchromax at $6.39/qt and MaxGear at $7.49/qt. Seems like a pretty good deal. Thanks!

[Kalevera]

Personally, I would use the Redline.

We used to distribute the stuff until RL started price gouging. We're currently trying Royal Purple and Amsoil, both of which are very good alternatives.

Aside: I've been taking apart diffs recently. I did about 8 E34 units earlier today. In the units with redline, the fluid "sticks" to the components. Anything else runs off. For Fritz, the extra cost in RL is worth it in my opinion.

best, whit

[Beez540]

Haven't used Purple in a bimmer, but I did in an Acura... fast shifts but terrible grinding. Switched to a newer, honda approved fluid and things vastly improved. Those trannys originally ran with motor oil, then honda noticed a short lifespan and designed a better fluid.

Always go with the latest greatest fluid the factory specifies. If you've had good luck with Redline though, stay with it I guess.

[gale]

Amsoil has just come out with a new manual transmission fluid specifically formulated for bronze syncro's. I'm currently running Redline MTL in mine and it works very well (after trying many other brands & types of fluid) but I will try the new Amsoil next time it's due for a change.

As for the diff, use any good quality brand generic GL-5 spec full synthetic gear oil, probably an 80W90 or 75W90 or 90W140 if in an extremely hot climate. Most synthetics don't require the special LSD friction conditioner, but it doesn't hurt to go ahead and use it anyway, or if you find you need it (groaning in low speed tight turns), drain a little fluid out & add the conditioner later, it usually comes in a 5 or 6 oz. bottle, Amsoil makes that too.

[ryan roopnarine]

i use the royal purple 75w140, as i have a lsd that spec's 75w140, and royal purple is the easiest to get syn w140 for me. doesn't groan, works well. mobil 1 75w90 caused my rear end to groan, which is why i upgraded. the new ford f150 uses 75w140 in its rear end, so expect prices to go up for the stuff when people realise a) they need it, and retailers realise b)people actually need it now. ive seen some valvoline 75w140 syn for 15.00 at discount auto parts, but back last year (the first time i changed it), my two options were royal purple w140 for $14.50 from carquest, or $18.99 from the ford dealership.