Hi, I have a 1985 300TD with some big concerns.

So I was taking the NJ Turnpike from Mullica Hill (South Jersey near Philly) to Staten Island and as soon as I got off the turnpike, I started hearing this 'thwopping' noise coming from the rear passenger wheel area, and as I get slower (< 15mph) it turns into a clunking noise, and at times with a noticeable clunking vibration thru the body of the vehicle. Almost like it's got a square wheel or the lugs are loose or something.

It's come and gone and is NOT consistent, but I've only driven it for about 4 days now. I did a 120 mile trip (each way) to/from Staten Island to South Jersey, TWICE (friday and today), and then a 45 mile trip (each way) to work on Monday. It only seems to be noticeable immediately after driving it fast (>75mph) and for over an hour or two. I can't say things conclusively because I experienced it today and so I don't know how it'll fare tomorrow. When it started on Friday, I got off the turnpike and noticed it at the toll booths. So I stopped, parked, turned the vehicle off, freaked out, and since i didn't see anything, I drove off. And it was totally gone. And today with the same long drive, I decided to keep on going instead of stopping and the noise/vibration persisted. It's almost like for some reason putting it in park somehow fixed/reset it, though I can't confirm (I haven't tested).

It really sounds like a clunking/thwopping like it's some gear assembly with a loose or broken gear trying to turn.

I don't see anything obvious in the back. I took the passenger rear wheel off to get a better look, nothing seems loose. The bolt that attaches the driveaxle to the rear arm looks totally tight. But my GUT says there's something of issue with the driveaxle. It really sounds like the gearing is damaged or loose.

I also did some brake work, replacing the rubber hose, cleaning the caliper, etc.. I noticed about a month ago that the hose was loose and that's why my brakes gave out within a week. I fixed that, but noticed the caliper was actually put on with the hose twisted - so really I think eventually it needs to be turned one rotation. I'm wondering if maybe the brake caliper is acting up.

I will say that I notice this clunking especially when I am pressing ON the gas. When I let up, the noise/vibration mostly goes away. So I'm kinda thinking it could be transaxle/drivetrain related (though it seems specific to the passenger side).

Can anyone confirm this is a possibility (likely or unlikely) or if there are other obvious possibilities?

Besides this, the vacuum system has decided to go haywire - there is a bunch of fluid stuck in the tubes and so the ignition wouldn't cut off. For now I am using a mityvac directly connected to the cut-off and manually pumping it when I pull my keys out.

It feels like the car wants to break down. Or break up. Either way I kinda feel like I want to cut my losses and just junk the thing (eventually). I may just keep it for round-town type of stuff. Until I notice things getting worse or consistently bad. I actually commute 90 miles round trip each day and so I don't want that stress.

I've actually already done a lot of work to just get it running safely.... The steering was unstable, the brakes gave out randomly, and the shifting flares between 3rd and 4th (I ease up on the pedal right before shifting so as to avoid the flaring).

I got the car for $500 a lil over a year ago, and from a guy who had it sit around who got it from a guy who had it sit around, etc... and it kinda goes back to what seems to be owned by a church pastor. There was a parking placard in the glove box. It's pretty clear that most of the work over the years was hacked instead of done right, probably because the guy didn't have a lot of money or because he didn't directly pay for it (the church did).

I'm honestly at a point where I have zero desire to even attack this project. I have a 300SD sitting around in the middle of a repair (leaking crankshaft seal, but the pulley bolts got stripped so I was stuck until today when I pulled the bumper off and used a strong drill with cobalt bits and a screw extractor) and also a Ford school bus I've been converting to a motorhome. I'm thinking I'd rather finish the 300SD car tomorrow morning if I can and if not take the chance with the wagon until the weekend. I've learned that I am CAPABLE of auto repair, but I'm at a point where I'd really prefer to not NEED to constantly fix something that is breaking after 25-30 years. I got enough stuff to worry about that I feel like I ought to just ditch all my cars and live in the motorhome and drive that around and when I can't find a place to park it (ie in the city), to either take public transportation or use my bike.

I will add that because of the vacuum clog, I've been running the tranny without the modulator operational for about 5 months. It hasn't been that bad. It's driven fairly consistently, though a bit jerking here and there, but I've gotten used to it. I'm wondering if maybe the jerking has caused some of the transaxle gearing to go bad.

I had a 300SD up until last year that had it's transmission give out suddenly. I didn't experience the same issues as this car, but I don't think the modulator was working either, and I'm thinking whatever happened suddenly to the transmission may have been related to the sudden jerks between shifting - ie maybe the connector plate between the engine and the transmission broke from the added stress or something.

Last time I had whopping thunking noises coming from the rear, it was exhaust hangers - some were broken. New hangers and she purred like new.

Check that first.

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Codifex
1981 240D ChinaBlue (Got her running with a donor engine.)
1983 300DTurbo w/sunroof.
1984 300TD manual sunroof. (Electrical Gremlins)

pull the wheel back off, and check the swaybar links. also inspect the axle boots, as torn leaking axles will indeed make a clunking noise on acceleration.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

The important word is inspection.

People have issues noises on their Vehicles and continue to drive them with out inspection to see what might be wrong often have serious failures.

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84 300D, 82 Volvo 244Gl Diesel

Sounds silly, but back the car up- say about 100 feet. See if the sound goes away for awhile. If so you can count on it being the rear boots being shot and it needing a reboot/grease. You can always fill the damaged boot up with grease, wrap the whole thing in rubber (from an inner tube) and use a couple twist ties to hold it all together as a temp fix until you can get it fixed correctly. The repair itself is pretty easy. Easier if you have access to a lift of course. My local garage charges me 60 bucks to put the car on the lift and swap out the rear end/axels etc. That's with them doing the work and me supplying the parts. He did the "Temp" fix for me for free. I know I'm not the only person to do the temp fix, as the 85 TD I just bought has the exact same "fix" done to it...

Personally, I would just get a set of them from Vstech, know they where done right (he has the correct tools for the job) and then not have to worry about it for the rest of my life.... (which for the record is exactly what I'm planning on doing for this 85 TD I have as soon as I have any spare cash)

If the outer boot is intact on that axle. Remove the small boot clamp. Inject some 70-90 weight oil with a turkey baster or tool of you choice. Three to four ounces should be enough.

Put a screw clamp back on. Your description covers a dry outer cv joint fairly well. Do not keep driving it this way or the joint might fail.

The outer boot is actually cracked and broken open in one spot.

I'm assuming the only way to take care of that is to replace the boot entirely, which means taking the driveaxle off the rear arm (the blue bolt that goes thru the middle of the rotor)?

If I'm already going to those lengths, should I just replace the inner boot too, inspect the joints (inner and outer) and lube them up?

I've driven the car for two more days now, commuting to work, maybe 45-50mph average, 90 miles round trip - and I have yet to hear (or feel) anything out of the ordinary. It's almost like it's the high speeds at long distances (75mph for 2 hours) doing this, somehow.

Is the cracked/broken boot maybe causing the lube to escape, via centrifugal force?

I have been working on my 300SD that's been sitting around (was able to get the stripped crank pulley bolts off and pulled the seal spacer ring off eventually), and was hoping to at least get that working for a few weeks before mucking with the wagon again.

I do not see why not. Actualy a lot of old cv joints could stand the addition of some new oil. Centrifical force tends to not make it a balance problem either. Only a couple of ounces though if the joints currently are quiet.

If the boots are not leaking I would consider it preventative in nature. Especially if looking at a long trip. For some reason even with no obvious leakage many joints get dried out.

Originally they had oil from new as well. Later joints or replacement axles may have grease. In my opinion oil is better.

I am a fan of used axles from wrecking yards if the boots are still in good shape for these cars. You cannot beat the original part quality and in most cases these cars are never scrapped because of bad cv joints.

When the axle is off the car flush or drain out the old lubricant and put new in. Get the used axle from the other side of the junk car compared to yours. New wear area goes into service that way as well.

The chinese axles have too many questions or isues and the new originals are too expensive.