Author Topic: Two questions (Read 2712 times)

DirtyD · « **on:** September 15, 2012, 04:19:29 PM »

I have a '91 318iS (e30) and haven't been able to find what type of manual transmission fluid I need to use. Any ideas?

Also, there is a wicked rattle noise coming from the Cat area on the exhaust i believe. It doesn't do it at idle, only during acceleration or when the rpms are too low for the gear. I haven't been able to pin point it due to it not making noise at idle. I have the shifter boots off and it is pretty wicked loud (and annoying) when I drive it. Has anyone had this problem?

One note for the exhaust noise, my cat is rusted on the backside and moves around a little but it does not make the same noise as the rattle.

help save my ears?

Alexdc12 · « **Reply #1 on:** September 17, 2012, 02:55:32 PM »

Prob the filters inside broken up

DesktopDave · « **Reply #2 on:** September 17, 2012, 04:39:04 PM »

I have a loose heat shield on my cat - it rattles like an old VW until it warms up. Might be a loose catalytic matrix as well, but I'd put a few sheet metal screws in the heat shield before destroying or replacing the converter.

There were three lubricants spec'ed for the e30 tranny from what I've seen. Look at the passenger side of the tranny for a label. Please double check these, but IIRC:
No label, 75w90 gear oil.
ATF label, use Dexron II (make sure it has no extreme high-pressure additives like Dexron IV, they'll wear out the phosphor/bronze synchros).
Special label, use the OEM BMW lubricant by Castrol.

Despite having said all that, I've tried a few different lubes - first was the ATF that came with the car. Worked just fine. I changed it with some full synthetic 75w90 gear oil in my tranny though it was spec'ed for ATF. Stiff shifting, grinding, took time to warm up. Once I went back to ATF, the car magically began to shift well.

DirtyD · « **Reply #3 on:** September 19, 2012, 01:35:18 PM »

Checked the heat shield but that is not where the noise is coming from. It sounds like the rattle is coming from the transmission area, between the engine and heat shield. I didn't have time to jack it up and look under there though.

DesktopDave · « **Reply #4 on:** September 19, 2012, 02:46:22 PM »

Maybe the exhaust pipe transmission mount off the tranny?

Does the rattle goes away or change when you push the clutch pedal in/out? A bad release bearing can rattle away a good bit. Hopefully it's not that though.

DirtyD · « **Reply #5 on:** September 20, 2012, 08:29:50 PM »

It had been a couple days but I drove her around today and the sounds does not go away when I press the clutch in and out.