Very noisy transmission

[mercedes13156]

Hi there,

I've got a C220 diesel which has done 193,000 miles. The transmission has been a bit "whiney" for months now, but has recently become much more noisy, which indicates imminent failure. The noise appears to be coming from the back of the gearbox and I'm thinking that it could be the coupling between the gearbox and the propshaft. The noise is similar to a failed wheel bearing and is worst during the first few miles in the morning both under power and under deceleration. After it warms up, there is a constant high pitched whine like a disk binding a bit (I checked and it's not the disks) and then the growl starts as it comes down through 20 mph to rest whether the brakes are used or not. In addition, the car will rock / roll about 6" each way against the gearbox when "P" is selected. Apart from that, it's running fantastically well.

Questions..... Am I right in my assumption? If I'm wrong, what could it be? Is it easy and cheap to fix myself? Is it just a case of trade it in for a newer model?

 

[BlackC55]

Sounds like a terminal box problem. Have you had the fluid changed?

 

[mercedes13156]

I'm not sure if it's ever been changed, but the gears are as smooth as silk. The noise seems to be behind the gearbox.

 

[Xtractorfan]

The rear axles in these cars tend to give up the ghost, quite a few posts on here about them check it out

 

[mercedes13156]

I asked the kids to locate the noise tonight. one thinks it's just under the gear selector and the other reckons its between the seats under the storage box. How about the prop shaft and its linkages?

 

[Parrot of Doom]

Theres a mount under there, check it hasn't failed. Its only a cheap little thing on the back of the gearbox.

 

[mercedes13156]

Thanks Parrot, I'll check it tomorrow. Is it easy to replace?

 

[Parrot of Doom]

Yes, just a jack and a bit of wood really.

 

[mercedes13156]

I had a look under the car and although it was hard to get right under, there did seem to be a bit of movement. I'll get the breeze blocks out next weekend and have a go if the weather's better.

Thanks for the help! Much appreciated.

Willie

 

[mercedes13156]

The next episode

I took the car down to our local garage this morning. The mechanic had a five minute drive and put it up on the ramp. The connectors at both ends of the prop shaft are in great nick. He reckons it's the bearing in the middle of the prop shaft which has gone. The rubber seal on the UV joint has perished and there's quite a bit of movement. It's going in soon to get replaced.

Thanks a lot for all your help guys. Much appreciated!!!

 

[mercedes13156]

Hi Guys,

I went to the local Merc Garage and brassed it a bit. I spoke to an older mechanic who said that the universal joint in the propshasft very seldom went, but that the ball bearing on the front section was probably the culprit because they did 2 or 3 a month on different types with high miles that sounded like helicopters.

I bought the bearing for £15 and its going to be fitted sometime next week at my local garage.

Thanks for the help.

Willie