Feels like I gained 30hp

[TowX]

Finally, after more than a year of procrastinating I had all the fluids in the X5 changed last week. Fresh Motul 7590 Synthetic in the front and rear diffs, BMW lube in the transfer case, and 5W30 Syntec in the engine (that gets done every 5000 miles). Trans fluid was fresh a few months ago when the trans was replaced under warranty.

On the cold mornings we've had recently, anywhere from 0 to 20F in the morning, there's so much less drag from the thick old lubes that it feels like I've gained 30 horses in the morning. And even after everything's warmed up it just feels much more responsive. Nothing changed but the fluids. Even my ex commented over the weekend when she borrowed if from me to move a piece of furniture, she asked me if I'd chipped it there was such a difference.

Nothing like fresh synthetic fluids to free up the drag on all the running gear.

[joeboch348]

your ex gf knows about chipping a car? can i have her number? haha my cars always seems to run better after the fluids are changed or maybe it's just knowing it has new blood in it.

[phil47]

How many miles on her (your X5)? I have around 40,000 miles on my 2005 and my SA mentioned not to bother until the next major service which is probably another 10,000 miles and 1 year away.

[jst2878]

Definitely simething that needs to be done. No fluids last forever

[TowX]

I've got 79000 on my X5. Like I said, I put it off for more than a year. Axle fluid had been changed at the 30K service but with BMW fluid because that's all the dealer would put in. Normally I like to drain and fill all drivetrain fluids every 2 years or 30K miles because I tow with it. With the new trans in it, I'll do a trans service at the end of every track season to keep the trans healthy.

Yes, my ex (ex-wife which is far more expensive than an ex-gf) knows about chipping. She used to track a 944, then my previous 911. Her Audis were always chipped, and she can adjust her own sway bars to dial in understeer or oversteer depending on the track. And when I get my current 911 back together with the new cage, and 100 more hp with the engine I'm building, I'll let her take it out a few times too. And FWIW, both of my sisters track their own 911's and drive modified street cars too, one of them a 135 sport.

[sprocket1200]

washing it will do nearly the same thing as you wash off a few pounds of dirt...

since you seem to be more atuned to your ride than most, i think the difference would be more in the 5hp range. many people can't feel the subtle differences, but i recently swapped a v8 throttle body onto my v6 Dakota and it made a very nice difference.