[Supahone]

So for a winter beater I picked up my 4th BMW in my stable a clean 2008 e90 328xi auto with 268,000 miles and the thing runs great, no codes and all for the whopping price of $500.00. It has changed my perception of mileage and durability. Regarding the transmission and differential
what would be the ideal fluids to use?

[Welcome to NBA Jam]

Killer find.

Transmission Fluid: Redline is a popular choice. Check their site for the right fluid. The OEM fluid is quite pricey and is made by Pentosin or ZF depending on if you're manual or auto.

Differential Fluid: Castrol Syntrax 75w90 is the OEM. It used to be called Castrol SAF-XO. Redline 75w90 GL-5 is also another popular choice.

[e91Owner]

Assuming you have a GM automatic transmission, the fluid is DEX VI. I've used redline D6 and found that it does not perform that well but YMMV. Currently using valvoline maxlife in the 6L45. So far so good, certainly shifts smoother. Probably the most common transmission fluid used by DIYers in any car.

For the diffs, I use liqui moly 75w90, but they're differentials, so there are plenty of options.

For the transfer case, there is only 1 spec to use: DTF1. Only a few brands and as far as I can tell they are all rebranded shell TF0870. None of them are super cheap, but the BMW branded one is certainly the most expensive. I used S-TEC since it was from FCP but there are other like rein, Febi & ravenol. BMW runs around $55 vs $30-40 for the others.

[Ozzie335i]

You might consider a brake fluid flush, and cooling system.

[Supahone]

Thanks for the replies. Duly noted.

[Efthreeoh]

Based on some previous threads here regarding the Xi failures, give the front drive shaft a good look over. They seem to fail at higher mileages. Probably a corrosion issue.

[Supahone]

Originally Posted by Efthreeoh

Based on some previous threads here regarding the Xi failures, give the front drive shaft a good look over. They seem to fail at higher mileages. Probably a corrosion issue.

Good point! thanks