I've been slowly familiarizing myself with my "new" 1984 300D, and this forum by far has been the best resource in doing so. This is an interesting car, with all the usual quirks, and as I go over my list of things that need to be done, I've been prioritizing them, at this point mainly focusing on things that should be done for sure before Winter. Two that I have questions on. Forgive me if I have not searched well enough and propose something redundant.....

First, how much play should there be in the rear of the transmission? I was looking over various things under the car, and I noticed I am able to physically move the tranny/driveshaft a bit, maybe 1/4 inch if I squeeze it with one hand against the mounting bracket near the rear. The motion is definitely because the rubber mount moves. I suspect it has softened? Is that worth bumping up the list? I do have some vibraration between 30-40 mpg while accellerating.

Second, the CV joint boots need replacing. Someone actually caulked them wher they've split with silicone, and I don't have noise or vibration in the rear, so probably the axles are okay. Is that a hard job for a fairly competent DIY'er?

I'll limit this post to only two questions to not drive anyone crazy...

Ben

an inch doesnt seem like too much to me.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I am already crazy, so I will just answer one.

If the transmission mount is original, you can bet that it could stand to be renewed, along with the engine mounts. The transmission mount is easy to replace. Having a small jack helps. (Otherwise, you can let air out of the tires, a trick I learned here at the asylum. They don't like us to have tools here.) The motor mounts are somewhat challenging because of access problems. But rewarding, nontheless. Your vibration could be due to a worn driveshaft center support and/or bearing. If you change those, consider renewing the flex disks at the same time. ("Renew" is a Mercedes term. On a Ford, parts are replaced. On a Mercedes, they are renewed.)

Caulking the axle boots? Well, at least the previous owner was an optimist.

the boots.

as the immortal red green used to say "this is only temporary... unless it works!".

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

My car vibrates/shudders whenever I slow down between the mph of 20 and 16, a weird quiver that I could swear is the tranny wobbling the car. I did my motor mounts, but the tranny mount is probably original, who knows.... I am thinking I might change it to see if I can get rid of the shudder, otherwise I have no vibrations at all, except around 90mph I get that same shudder, probably the tranny again......

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I experienced pretty much the same thing after I changed the mounts. But it ceased when I replaced the driveshaft support and bearing. The old bearing seemed okay, but the support rubber had seen better days.

Wouldn't it vibrate at other times though? Its completely vibration free when accelerating. Only slowing down between 20 and 16mph is when it wobbles....otherwise....nothing......

If it is indeed the carrier bearing I am going to leave it be until I change out my rear cv shafts/differential in the future, I'd just have all that done at once. Unless it gets worse of course....but its been the same for about 8 months/10,000 miles....annnd, sometimes it doesn't do it, especially if I slow down by coasting a long ways and gradually slowing, which leads me to suspect tranny mount, because the tranny has more reason to move/wobble under a fast deceleration than a long drawn out one....

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

As long as the "caulk" jobs holds you should have no worries. Watch for oil dripping from the boots. When that happens it will only be a matter of time. At that point you'll have two possible solutions:
1. Replace the axle shafts. There are lots of threads here on how to do this and where to buy replacements. It's definitely a DIY job that anyone with moderate skills should be able to accomplish. The only controversy seems to be over the type of axle replacement to use. If you choose this route you should be able to wait until the CV joints are getting be be pretty noisy before the job HAS to be done.
2. Replace the boots. A number of people here are not fans of this approach but I have done it successfully. If you choose this you'll need to do it as soon as the boot starts to leak and while a simple job, it is tricky to get right (it requires keeping everything very clean in an area that is usually very dirty). Needless to say this approach is cheaper. You'll find threads on this procedure here as well.

So you just pays your money and makes your choice. Good luck.

__________________
LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

Thanks. Interesting stuff to look for. The age of the mounts are entirely ambiguous, as the engine is a factor replacement dating to 2001, resulting from the dealer not tightening the oil drain plug after servicing the car for a previous owner. The tranny was supposedly rebuilt at the same time, but I have no verification of that. Flex discs look okay. Some of the wobble went away when I discovered the exhaust hangers had been replaced with wire by the guy I bought it from, and it's less noisy to boot.

But I still have that vibration/wobble accellerating.

ben