Auto-Manual Tranny swap in need of advice - PeachParts Mercedes-Benz Forum

jaysun9 · #1 05-02-2008, 02:02 PM

Greetings, I have just finished moving through the auto to manual trans swap and thanks to all the folks out there who have put so much useful info on this forum.
Got in the car for the first test drive and tranny shifts great into first gear and next thing I know as the RPM's begin increaseing the vibration around the tranny becomes intolerable at best. It's definately not the driveline and appears to be happening inside the bell housing. Only thing I can think of is the balance of the 240 flywheel mated to the 300 turbo engine.
I guess that my question to put out there is does this sound like an accurate assesment of the situation and how important is it to have the flywheel re-balanced to match the old flywheel.
I'm at the point of frustration on this one and any help out there would be greatly appreciated.
Thanks much.....J

winmutt · #2 05-02-2008, 02:14 PM

What makes you think its not the drive train? Pull the DS from the back of the tran and run through the gears and RPM. I dont have a problem with the 200D flywheel in mine? *Some* flywheels were not neutrally balanced but I have yet to find anyone who has had that problem. 10:1 is the drive train. How did you mount the rear tran mount? Which one did you use? How big is the angle in the U joint? How is you carrier bearing/bushing?

jaysun9 · #3 05-02-2008, 03:24 PM

Now that you mention the related components I'm not sure that its not the drivetrain. I used the mount from the 240D and mounted it perpendicular to the trans and having to modify a mount hole in the passenger side of the mount. I'll try pulling the DS this afternoon after work and see if the vibration subsides.
Maybe you could school me on the topic of the U Joint angle. Do you say that as the angle that it sits at as its mounted from trans to dif?
Also what is the carrier bearing.....
Thanks for the help!

Bajaman · #4 05-02-2008, 04:08 PM

The carrier bearing is what supports the center u-joint. Check the rubber and function of the bearing. I didn't follow your description of the vibration. Some have noted that if you drop the rear of the tranny it will reduce the vibration. I tried dropping it about 3/16" with washers between the 240 mount and the body, but it didn't help any...

rstl99 · #5 05-02-2008, 04:16 PM

Quote:

Originally Posted by jaysun9

Greetings, I have just finished moving through the auto to manual trans swap and thanks to all the folks out there who have put so much useful info on this forum. J

Hi There.
I've occasionally toyed with the idea of swapping my perfectly fine auto trans to manual (if I ever found a donor car nearby). For the more fun driving experience, mostly. Thought it might make a good post-retirement project in a few years.
Having done the job, would you do it again knowing what you know now? Work involved, hassles, etc.? I'm a shade-tree mechanic, but getting older so crawling under cars is not as fun as it used to be.
Thanks!

Stevo · #6 05-02-2008, 04:41 PM

I have made several 616 auto to manual tranny swaps and only had one with witness marks on the flywheel and crank, that was my 79. I have been flying by the assumption "no marks=neutral balance", but you know what they say about assuming

anyway I haven't had any vibration problems.

t walgamuth · #7 05-02-2008, 05:32 PM

Stevo may be right but the witness marks on my 280e were so subtle as to be invisible to this nearly sixty year old set of eyes!

Be careful.

Tom W

winmutt · #8 05-02-2008, 05:58 PM

Quote:

Originally Posted by rstl99

Hi There.
I've occasionally toyed with the idea of swapping my perfectly fine auto trans to manual (if I ever found a donor car nearby). For the more fun driving experience, mostly. Thought it might make a good post-retirement project in a few years.
Having done the job, would you do it again knowing what you know now? Work involved, hassles, etc.? I'm a shade-tree mechanic, but getting older so crawling under cars is not as fun as it used to be.
Thanks!

I would never go back. The hardest part is getting at the top bolts. I couldnt figure out why the neighborhood kids were giggling till I realized I was humping the engine bay.....

t walgamuth · #9 05-02-2008, 06:29 PM

It is most sensible when done at the time the automatic fails. Then its cheaper and better to convert to stick.

Tom W

Stevo · #10 05-02-2008, 08:41 PM

Quote:

Originally Posted by t walgamuth

Stevo may be right but the witness marks on my 280e were so subtle as to be invisible to this nearly sixty year old set of eyes!

Be careful.

Tom W

I definitely gota put on my reading glasses and use fine emery cloth to hunt for them.

jaysun9 · #11 05-05-2008, 05:03 PM

Alright guys,
spent the weekend tinkering with the driveline (did a few tests and it was obviously the driveline.....Thanks for the tip on that one). Ended up working with the rear trans mount and playing with some washers trying to dial in the spacing and center the mount as much as possible. Just curious how you guys have lined up your mounts to get the line nice and straight. I'm at the point now where I am on the road again and couldn't be more excited about it. Nothing like driving a 84 manual 300 cd!
Anyways I still have a little vibration happening around the low rpm high torque arena. Any tips on aligning the tranny mount to perfection would be sweet...And by the way how much vibration is typical for this conversion. Thanks for a the help out there!

winmutt · #12 05-05-2008, 06:08 PM

Quote:

Originally Posted by jaysun9

Alright guys,
spent the weekend tinkering with the driveline (did a few tests and it was obviously the driveline.....Thanks for the tip on that one). Ended up working with the rear trans mount and playing with some washers trying to dial in the spacing and center the mount as much as possible. Just curious how you guys have lined up your mounts to get the line nice and straight. I'm at the point now where I am on the road again and couldn't be more excited about it. Nothing like driving a 84 manual 300 cd!
Anyways I still have a little vibration happening around the low rpm high torque arena. Any tips on aligning the tranny mount to perfection would be sweet...And by the way how much vibration is typical for this conversion. Thanks for a the help out there!

Everyone complains about the low rpm high torque issues. I have never run into it after I lowered the rear of the trans a bit. (I have OEM setup) There is a dampener which may or may not help with this issue. I am betting it is still avail but probably has to be ordered from the father land.

jaysun9 · #13 05-05-2008, 07:45 PM

Thinking I will just play around with adjusting the trans mount height and see if I can find the sweet spot. By the way, what is the OEM setup?

R Leo · #14 05-05-2008, 07:52 PM

Quote:

Originally Posted by winmutt

I would never go back. The hardest part is getting at the top bolts. I couldnt figure out why the neighborhood kids were giggling till I realized I was humping the engine bay.....

Drop the back end of the tranny and go in over the bellhousing from under the car and use an 18" and 12" extension connected together to reach the bolts or cap head screws. Much easier/faster/less embarrassing than "humping" the valve cover.

winmutt · #15 05-06-2008, 11:19 AM

Quote:

Originally Posted by jaysun9

By the way, what is the OEM setup?

Well using the correct OEM parts without modification. My old car was a euro 300D manual with a trashed body. I have the correct trans mount, DS and balancer. I took the flywheel from a 200D without issue.