300D Noise

Hi all,
My 83 300D has been making a strange thumping or loud sputtering sound when I drive on trips of 14 miles or greater. I live 45 miles from where my fiancee now lives, and when I drive to see her my car starts to make this sound at about mile 14 or so. Also, during my commute to work (which is 14 miles one way, that is where the 14 number comes from), just before I get there is when the noise begins to start up. It's quiet when it begins, but gets louder and louder the longer I drive. It's funny to see the kids waiting for their school bus watch my old heap as I drive by. At first I thought that it was the bearings on one of the back wheels that were somehow agitated as their temperature increased while driving, but the sound only happens when I have my foot on the gas pedal. When I coast, the sound does not happen. I do have a fuel leak that I haven't been able to fix yet. I wonder if this has anything to do with the leak?

Any ideas?

[bill murrow]

Might want to check your driveshaft. Could be the center support bearing.

Cheers,

Bill

[d.delano]

Check your rear axle boots. If they are cracked or torn, further check for signs that the packed-in grease was slung out through the breach in the boot. A dry CV joint will make a noise as you described.

[junqueyardjim]

Girlfriend that is. Perhaps one closer to home.

[didget69]

Sound you describe is most likely a shot CV joint - just cured my car of a similar noise. Put in a $100 used 300D axle complete, no more clonking!

Bryan in NC

I spent a good part of last Friday patching my leaky fuel return line. I managed to a get a lot of dinodiesel onto my driveway and myself in the process. Needless to say, it wasn't pretty.
Yes it does look like one of my rear axle boots is split. I noticed that it was split when my nose brushed up against it while replacing the fuel line. Is this a difficult repair? Is it super expensive? I read didget69 replaced his whole axle. Hmmmm...I'm beginning to think that this car as my only source of transportation is not such a good idea.

[didget69]

Hey "Stimpy",

Axle is not hard to replace, if you have tools & space. I'll try to list steps from memory here & others can correct as needed...

With car on jackstands/lift, remove rear wheel. Remove axle nut at wheel. Support differential & remove rear diff cover - WARNING! - Rear cover is what holds the diff in car! Make sure diff housing is supported well!

Next, remove axle retaining clip inside diff housing. Using brass drift, at wheel, tap axle in toward center of car; this will remove axle shaft at wheel ("collapses" CV onto splines of axle, if this makes sense). Then pull axle at diff side out towards wheel; axle should come free in your hands & drop down from car.

Good time to replace axle seals/CV boots/check CV condition/etc. Reverse procedure with new/used/reman'd axle assy & refill diff w/ proper lube.

I did mine in @ 1 hour - purchased used 300D axle from local MB salvage yard for $100 - WARNING!! - If you get a used axle assy, get the one for proper side of car; i.e., if left axle is bad, get salvage left axle, right for right. You want to keep them oriented in same rotational direction.

didget69 / Bryan in NC

[Lycoming-8]

Didget,

Why do you suggest using used Half-shafts on the same side of car as previously installed? Several on the forum have hypothesised that we could take advantage of the unused races for the other direction and gain quite a bit of lifetime on the replacement. Am interested to hear what your thoughts are on this.

[cjlipps]

My problem sounds identical. Happens after about 35 miles at highway speed and gets worse as I roll along. A complete stop completely cures the noise. Haven't gone the next 35 after a stop yet since I am almost at the end of my commute. It sounds like a tire thump or a wheel about to come off in the beginning then escalates to a terrible knocking. Reduces upon deceleration and worsens upon acceleration.
Does this sound the same to you guys? Haven't inspected the boots closely as of yet but at a glance they look greasy.
Thanks for any and all help.
Chuck.

[Isleham]

Same thing happened to mine. I got a 75 dollar half axle at Carquest with a life time warantee. Lasted 6 month. Took it back under warantee, got another one. Been driving all over the eastern US 3 years now. something about original direction of rotation before it was rebuilt. I guess you would have a 50/50 chance.