knocking - BMW Forum

SILVER 325 · 04-17-2006, 02:05 PM

hi guys just came back from a bmw show in my 325i coupe e36 but i have a problem
when i go through the gears at normal speeds the car is fine
but when im in 1st gear and i put my foot down the car makes a knocking sound almost the same as when you brake and the abs kicks in like a clicking i then go to 2nd gear it does it slightly but then stops when the speed builds up.
my exhaust isnt rattling had that checked so im thinking the diff??????
can anybody shed any light as to what this could be if anybody asks any questions il do my damned hardest too answer thanks in advance guys

Furious · 04-18-2006, 12:58 PM

thats hard to understand the noise. do you think its tranny related? or does it sound like the engine?

e36surge · 04-18-2006, 02:04 PM

Prop shaft coupling?

My buddy kept complaining about a knocking with similar situation you've discussed. He had his replaced and he didn't have any problems. It's a little rubber piece. There is also a bearing that goes sometimes. Found on the drivetrain driveshaft going to the rear differential. This may be your knocking noise.

You can check the oil level on the diff by unscrewing the top filler hole pointing towards the back of the car. Level should be even with the bottom of the filler hole. But I doubt your diff is the cause. The knocking would persist throughout all rev ranges and speeds and would eventually result in a humming sound coming from the back.

There is a recent thread on this site. Try searching the site for 'prop shaft coupling' And then try a google search as well. The part is not expensive. The Bentley also has the procedure to replace.

Also make sure to check your rear universal joint from drive shaft to differential.

Tell us what happens.