Gearbox/Transmission Mounts

[Kompressor_Dude]

Hi guys, i've had a good search of the site and cant find any info. on my problem.

my C230K needs a new exhaust, and while it was on the ramps the mechanic pointed to the gearbox, which was moving around all over the place. He said the mount was probably buggered.

Now i've been to the dealership and bought a new one - just wondering about fitting. I have a reasonable ability on mechanics (well, i can follow a how-to on most basic maintenance :) ) but have never worked on a car like this before.

Is this an easy job or am i best just going to a garage? what will i need to complete it? i have a full tool kit, but im guessing a jack to support the box (its a manual) and some axle stands will be needed.

If anyone has any more info. or can do me a really quick 'how to' so i've got a guideline i'd really appreciate it! it's off for a new centre silencer and custom backbox soon so i want to save the labour charges of a garage for the mounts if possible.

Thank-you to anyone who can help, its much appreciated! :)

[Pagz]

Hey man,
it should be pretty easy to replace,i cant remember if you need to remove the exhaust,or even remove the cross member,but you need to jack the car up and put axle stands in,then use the jack to take the wieght of the gearbox while changing the mount.
i will check the manual tonight as i can then give torque specs as well.

[Kompressor_Dude]

that'd be great mate, thanks! if the exhaust has to come off then sod it, it can go to the garage :) dont feel brave enough for that kind of work!

[Pagz]

Damn forgot to get the info,some parts turned up and iv been working on her every night till midnight this week =),will check my book today and get back to you..

Paul

[c280nz]

yea im pritty sure the exhaust has to come off,
well it does in the c280 anyway.
and those exhaust/into/header bolts are always hard to get undone,
are you sure it is your gearbox mount and not your engine mounts?

[Kompressor_Dude]

Nope, the exhaust is blowing and the gearbox was all over the place, only thing i have to go on that the bearbox mount is the culprit is the fact that the mechanic said it was that! Got the part as it's cheap and cant hurt to replace. A garage offered fitting of the part for £20 so i might do that to save the hassle. Getting the exhaust off will be a pain :(

[xvvvz]

I have never done it, but for only 20 pounds I doubt the shop would have to remove the exhaust. Additionally, for what its worth, the Haynes manual does not describe disconnecting the exhaust as part of the transmission mount removal procedure. They do note a "splash guard support" that must be removed but that sounds pretty simple and obvious.

Let us know how you get along!

[Kompressor_Dude]

So torn! Part of me wants to give it a go as it looks so easy, but for the price of buying axle stands i could have a professional do it :)

I'll let you know how i get on, if i do it myself i'll do a 'How-To' with pictures as I just got a copy of the Haynes Manual and it's pretty non-descriptive....

[xvvvz]

Page 2A-29 was the best I found although, as you say, it isn't super descriptive. Hopefully that means it is so easy it doesn't need much description :) The jackstands will be a good long-term investment for all of the other projects you will need to do. I say go for it!

[Pagz]

I reckon buy the axle stands and go it yourself as well!,even though my exhaust isnt OE it still follows the same path,which is around the mount to chassis braket,so it wont be an issue to follow the haynes manual without dropping the exhaust.=)

[Pagz]

Just noticed i had a pic...
Should be no problem to do!

http://memimage.cardomain.net/member_images/3/web/735000-735999/735658_301_full.jpg

paul

[Kompressor_Dude]

http://i74.photobucket.com/albums/i274/DJ_Superman/enginemount.jpg

so i jack it up on the cross to support it, undo the four bolts on the metal part and take the mount off from underneath it??

Thanks for the pic!!

[c280nz]

yes the mount is ontop of that plate,
undo all 6 of those bolts and youl see it,
but the bolts which go into the gearbox are hard to undo, theres a nut on the gearbox end which is in a tiny hole and i had to use a rattle gun and ram a screwdriver in to stop the bolt spinning.
im guessing yours will probebly be similar, altho youl see when you get under that plate.
have fun

[Kompressor_Dude]

Thanks for the advice.

Is there any chance of me losing the bolts in the gearbox? Hope they cant fall out etc. once unscrewed.

And I dont have a rattle gun.......... will have to rely on 'the guns' instead :D

[Pagz]

Nice drawing!=)
As Logan said,on the manual transmissions theres a square nut that slides into a cavity in the side of the gearbox which could turn if the bolts are seized,so you wont loose anything inside the gearbox...an yer those ones are done up to around 70Nm so could be quite tight...get those guns a blaz'n:D

[c280nz]

Originally posted by 23K
Nice drawing!=)
As Logan said,on the manual transmissions theres a square nut that slides into a cavity in the side of the gearbox which could turn if the bolts are seized,so you wont loose anything inside the gearbox...an yer those ones are done up to around 70Nm so could be quite tight...get those guns a blaz'n:D
oh they were only ment to be done up to 70nm :embarr:
haha, yea what a stupid design those bolts wer.
paul have you seen inside your g/box b4?
mynes in a million bits on a bench at the mo :D il post up some pics when i get them loaded on to the computer

[Pagz]

what the!?!?...lol what happened to your box?....I havent seen inside mine,i had it stripped down and checked because i thought it was worn out...turns out its just crap hehe.
pics are gOod=)

[c280nz]

Originally posted by 23K
i had it stripped down and checked because i thought it was worn out...turns out its just crap hehe.

haha man that is so true and cracked me up :-)
it was wuring a bit so i decided to rip it apart and replace all the bearings,
everything else in it is pritty gud.
you know your geting to be a good diy'r when your tackling jobs like that at home.
im just waiting on the new bearings to turn up at my local dealer then il chuck her back together :)

[Pagz]

haha yer the guys just did bearings and seals etc,the syncros/gears where all good.....which was unexpected after i drained the chocolate oil from it!!!

...haha Im never taking mine out on the garage floor ever again lol...man that sh!ts pretty heavy when you've got 1 foot of room and frickn god knows how it came out cause it jams on the trans tunnel when trying to align the shaft...man so close to loosing the plot that day=)

So are you re-assembleing it yourelf???...must say i tried but couldnt get that drive shaft nut off!.
are you replacing the thrust and pilot bearing too?

[c280nz]

you get the driveshaft nut off with a deep socket and a rattle gun.
and the gearbox is way easier to line up if you jack the front of the engine up so it tilts backwards.
yea we shud be able to put it back together ourselves.
im replacing all the bearings throughout the gearbox, thats about 10 of them, and the pilot bearing, but i prolly wont worry about the thrust bearing
its to expensive :-(
all the bearings all up came to 300$ from the merc shop.
and yea the syncros were mint as

[Kompressor_Dude]

I dont have a torque wrench, will have to just do them as tight as i can :)

Would like to see the inside of the box, hope its something i never have to do! Good luck :D

[Pagz]

Originally posted by c280nz
you get the driveshaft nut off with a deep socket and a rattle gun.
and the gearbox is way easier to line up if you jack the front of the engine up so it tilts backwards.
yea we shud be able to put it back together ourselves.
im replacing all the bearings throughout the gearbox, thats about 10 of them, and the pilot bearing, but i prolly wont worry about the thrust bearing
its to expensive :-(
all the bearings all up came to 300$ from the merc shop.
and yea the syncros were mint as

Ahh true!,that was back in the day before i had air tools=),
I had the engine tilting downwards at the rear as it naturally does if you dont support it!,however i never jacked the front!
,cant remember how much the gearbox shop charged it was around 1000 including bearings etc,they delaminated and thoroughly cleaned it out though.

Your damn keen man hope it all goes back together well=),have you got the car on the hoist?

[Pagz]

Originally posted by Kompressor_Dude
I dont have a torque wrench, will have to just do them as tight as i can :)

Would like to see the inside of the box, hope its something i never have to do! Good luck :D

yeh man just change the oil,your box will be fine=)
im sure you could find somone with a torque wrench!,best to do it right the first time!...I could shoot the guy who last did my AC pump bolts,they stripped inside the Alloy braket when i wound them out.

[c280nz]

yea il take some pics and show u guys wot it looks like.
no hoist just sitin on axle stands and tires.
yea il clean the gearbox out properly b4 i put it back together.
at first glance tho describing our gearboxes, they arnt the strongest design,
1st and 2nd seem pritty solid, 3rd prity weak, and 4th and 5th look reasonable.
gearboxes arent that complicated, you just undo all the nuts around the outside and the whole gear clusters come out together, so far the hardest part has been removing bearings.

this is all being done by two people who have never pulled a car gearbox down b4, let alone an un-heard-of mercedes box :-) were just good at solving problems and figuring things out. and its a pritty simple layout in there :-)

[Pagz]

Wish i had done mine myself now!!...there could be a next time though=)..yeah bearings can be a pain,you need the right pullers for the job i guess!..must get me a proper bearing puller set,and a quality set of dies an taps,a bench drill,a bench grinder + belt sander,a lathe and a huge vice=)...building a garage in the coming months so maybe ill finally get me a workshop=)
Yeh some pics would be great!...so third looks weak?...,wierd?

[Kompressor_Dude]

Another quick question for you guys as you seem to know your stuff :)

The centre silencer and back box are both blowing on my car, if i replace them with a custom back box but no middle silencer will it become really loud?

My mechanic said 'cos of the supercharger it'll be like thunder but if i can i'd like to get rid of the stock mid/back boxes and replace with a single custom dual-exit back box, like the lorinser one.

Dont mind it a bit louder, dont want anything erm.... what do you call it...... Ricer?

So will i get away with just asking for a back box full of baffles :D

[Pagz]

Originally posted by Kompressor_Dude
Another quick question for you guys as you seem to know your stuff :)


"Seem to",yip hehe

From past experience,the cam profile on the M111K makes for a very loud exhaust tone,if your planning a striaght through system it will be loud!,I once did a 2.5' system from the header back...it consisted of two straight through mufflers in the middle with one being partially chambered,and at the end i had twin straight through mufflers like VIP_BENZ had on his supra(if you saw that thread)
the noise was unbearable...the resonance gave you a headach in minutes,so i installed the C36 muff which is a reverse flow chamber setup....pretty quite after that=)
However i dont have a cat.

You could start by chopping the rear muffler off and installing the muffler of your choice,if its too loud i would look into a non-straight through design for in the middle somwhere.

Definatly keep a centre muffler,trust me.

[Len013091]

Yea, on the muffler thing, leave the resonator in. It makes my car sound really deep, not like a honda or anything. Magnaflow mufflers sound great on the car. The OBX one the guys at the shop tested on there wasn't bad either.

[Kompressor_Dude]

Thanks guys, point taken! I can get a standard centre silencer box for £75 so i'll get that and have them fit it when they do my custom back-box :)

[Kompressor_Dude]

What gearbox oil should i be putting into my manual box? Garage have said they'll change it for £10 if i can source the oil myself but iv got no idea what needs to go in.

The haynes manual says use ATF (Automatic Transmission Fluid) in the manual, but is this ok for the kompressor too?

[c280nz]

yes that is correct, use atf what the manual says.
they take a bit over 1 ltr, if u buy two ltrs u shud be sweet