I have replaced both axles in my 83 300TD. Fair warning is do not buy the cheap Chinese axles they sell at Advanced Auto Parts. I think they were $70 each for brand new axles lifetime warranty or whatever. But within 100 miles they were spraying oil! My friend put them in his VW Rabbit Caddy...same story.

I went and bought a good new set, been on the wagon for 3 years now and no problems.

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1983 300TD - 202k with 5 speed Getrag conversion

Got the Ultra 8 from Napa a few years ago for the 80 wagon. I could'nt put the spacer rings in cause they did'nt machine the filets on the stubs that fit into the diff at a complete 90 degrees. They were $99 each. I can't get axles for less than $285 (core included) around here now....and they are the Cardone's. I am not sure but I think someone on here said that these are'nt very good quality either.
I imagine these ultra 8's are the chinese ones. The 80 wagon has lost its transmission. I wonder if I lost the fluid out of the axles causing this trans. to go.That's another story.

Took the 85 for a test drive and it does not squeak in reverse anymore. Engine temps are also a hair cooler on the freeway, and does'nt fluctuate as much. I think I have been driving around with a dry axle....who knows for how long. It was all pretty insidious, and it did'nt make any noise except backing up.

There is still something not quite right though. The diff is really hot to the touch and I don't think it was like that before. I put the laser gun on it and got a reading of 60 degrees celcius. I don't think that is right. I''ll drive it for a few days and see how the fuel mileage does. I maybe overthinking this diff temp thing. I wish I would have taken a reading before all this work was done to compare before and after. Still could be a bad diff. but I don't want to believe that. The fluid that came out was pretty clean and from what I could see it looked good in there. I might have put a bad used axle in to replace a bad axle like twalgamuth suggested.

I took it for a pretty good run up and down some steep hills so maybe that is what made it hotter. Anyone have a temp reading on the diff case for comparison? I think this could be a good troubleshooting tool.

I checked the brake disc temp and that rear drivers side rotor is 38.9 degrees celcius.....the rest are 37 C. I may have a dragging brake that has lead to this axle problem or they are not related and it is just a coincidence. This time, I measured the temps right after driving it hence the increase over previous readings posted. The almost 2 degree difference on that wheel now is both puzzling and disappointing, but perhaps because I took a reading immediately, it is more accurate...and I am paying closer attention to exact numbers. The difference suggests something is not right with the brakes.

Thanks.

While I was typing the last post the car has been sitting. I went out and rechecked the temps. It has been about 20 minutes since the first reading. I now get:
32.3 C on the drivers side rear rotor
31.0 C on the pass. side rear rotor
31.7 C on the driver side front rotor
32.4 C on the pass. side front rotor

The diff cover temp is now 45 degrees Celcius. It is no longer hot to the touch after 20 minutes. In the past when checking this diff cover by hand I had waited about twenty minutes so I am no longer worried about diff temps. I think it is normal. The 60 degrees that I posted a reading for was immediately after turning the car off.

This car is giving me F*****g OCD, I am ready to throw in the towel on this piece of %$#@#$ and maybe even Mercedes altogether. It seems that every time something gets fixed something else comes up in need of repair. I have gone from the front to the back fixing stuff and have a small fortune into it, now. The parts have increased in cost about four times since starting this hobby five years ago. Boy it seems Mercedes with their increase in prices want these cars off the road which is probably a marketing mistake on their part.

The only thing keeping me going now is that I have learned alot....I now know what I have...engine does not leak a drop of anything....I could eat off of it....the transmission leaks nothing and to the credit of the car it has gone over half a million killometers on what appears to be original everything. With the diff /rear end problems I have literally gone front to back. I have also become very patient but if one more thing goes wrong with this I won't be able to claim being patient anymore....or perhaps with this rant it is already too late. Sorry, but smelling like gear oil gives me a headache....I can barely tolerate the stuff and have dry heaved several times today. I smell worse than s**t.


I need a break from this. Thanks for all the help, guys I do appreciate it.

I am sorry you are discouraged with the car at the moment. The differentials seldom give trouble. Not being fluent in celcius I don't know what temps you are giving.

What I do when I get to this point on a car is lay off it for a day or so, get a good nights sleep and usually I will think of another way forward to attack the problem.

Good luck!

any chance your rear tires are different diameters?

__________________
[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.

Thanks for the kind words of encouragement and advice...just frustrated for a second. I am not in the best health to be fiddling with cars in the first place, but I have no choice.

I guess I will be taking another reading at which point I will hit the temp designation to farenheit for our American brothers. It would be nice to have some references for all of us...not that mine is worthy of being the reference car, but we can compare amongst ourselves and use it somewhat as a guide maybe. These temp guns come on sale once in a while and are now pretty cheap. I think I paid something like $35 for mine a few years ago. I don't know how accurate it is which might become a problem when comparing, but it is at least something to gage serious issues by.

I just had new tires put on last week. I had a set put on three weeks ago but I did'nt like them so I ordered the tire I actually wanted in the size I wanted and they exchanged them last Tuesday....215 65-r15 on w126 aluminum wheels all around.

Did the shop tighten the lug bolts all the way down with an air gun? If so did they use a torque stick?

Or were the wheels snugged on with the gun and then final tightening on the ground with a torque wrench?

__________________


Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

I am not sure. They were done at Costco, so whatever they do there. I did see the guy zip them on partially with an impact. I found them to be a bit on the loose side when I removed the wheels on the back. They are on now by my method. I am suppossed to take them back to have them re-torqued as per their 40 - 60 km requisit.

Come to think of it......it actually looked like she was using some sort of a yellow platform under the front wheels at one point when I peaked in on it. She had the car in the air just barely above the ground and it appeared the yellow platform thing was wedged under the tire...she had a torque wrench in one hand but then I left. Maybe the yellow platform thing was in place to hold the tire while she torqued it with the wheels off the ground.

What's a torque stick?

It's an extension with a specific torque value that's used on an impact gun... once the nut or bolt reaches the torque the shaft flexes in synch with the gun to prevent further (over) tightening. I believe they are usually colour coded by torque value.

Around here they have an awful habit of staying the drawer in too many shops.

I had 2 tires changed by a small local shop this spring. I remember the wrench's pal arrived as he was working on the right front and they started chatting.

A few days later I was getting a strong burning smell after a 10-km run on secondary highway. Then pulling away from a light it felt like I had serious rolling resistance.

I was close to home so I kept going. When I got in I shot all the hub areas with my temp gun. The right front was I think 72 C the others were somehwere in the high 30s.

When I loosened the bolts on that wheel, I had to STAND and rock on the breaker bar for two of them.

So that is why it caught my eye, when you mentioned the tire install.

I had planned to bring my torque wrench with me, to the shop, and forgot. Why I didn't ask the guy to use his (properly, to tighten with the wheels on the ground) remains a mystery to me....

__________________


Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

I got some farenheit temperatures after my second and longer test drive tonight with both city and highway driving:

95.2 F on the drivers side rear rotor
95.6 F on the pass. side rear rotor (hotter than this afternoon)
95.3 F on the driver side front rotor
95.4 F on the pass. side front rotor

They are all about 95 F and there is a discrepancy by a small amount between the readings I got in C and F from this afternoon. This seems normal and they are all fairly equal regardless. The difference could be from several variables such as how far from the object the gun is or the spot I picked to shine the laser on to get a reading could explain the small difference. I did choose roughly the same spot on the rotor each time but it is not like I put it in the exact place for both measurements of temperatures. Temps. are close enough to rule out dragging brakes????

The diff. measured at 145 degrees Farenheit. or 61.5 C which is about the same as this afternoons reading. (1.5 C hotter)

I also measured the metal caps at each cv joint and they were equal to each other. Actually this time the pass. side metal caps were hotter by one degree C. Drivers side metal cap at cv joint was 35 C.
Pass. side was 36 C.I did not hit the F button when I did that but it should be about 95 F.

.....I am happy with the repair and it is definately better than it was. No more dragging and engine temps on the highway are the sliver lower that I was looking for...the squeak in reverse is gone. I will probably need to reboot this replacement used axle on the drivers side rear soon, cause the rubber looks dry, but there are no tears and it is working better than the old one it replaces.
.....Being the same temp as the pass. side that does have a newer boot I think this axle might be a good one. I will call this repair successful for now and would like to run some diesel through to see the mileage effects.

I hope driving it for however long with that axle the way I found it has not damaged anything major like the transmission. I am starting to think if the engine was running hotter.... then the trans would be working extra hard as well. The fluid looks and smells fine and shifting is good so perhaps being picky about the small difference in engine temps. has paid off and staved off further damage by catching this early.

I think these cars are designed so well that these drivetrain issues can be so insidious in symptoms that unless you pay attention and keep an eye on things you could drive some of the more expensive components into the ground from neglecting various minor or what appear to be insignificant parts.

Doing the head on this car has put me in tune with how it should run and has helped me throughout the diagnosis of working through to the more minor and perhaps even parts that may have even caused other problems I have already dealt with. This is what I learned this summer...the knee bone is connected to the leg bone....and the neck bone is connected to the head bone.

Thanks again for the help and for being great teachers of this hobby.

Now perhaps you are getting overly concerned. I cannot imagine how the engine running a little warmer will affect the tranny. Did you check the level in the radiator? Anytime you drain the coolant it is essential to get the engine warm enough to open the thermostat to get all the air pockets out of the system.

I'm not sure what temp the diff should run. the only things I can imagine that would run the temp up on that would be:
1. Running two different sizes tire on the rear, working the diff constantly while running down the highway.
2. Some sort of bearing failure inside the diff.
3. Low lubricant level in the diff or water in the lubricant.

__________________
[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.

Yes, perhaps I am thinking this to deep... but if you think about it this way...If you are dragging a brake for example, and the engine is straining to propel the car forward to the point that it is raising the temp of the engine then this would also affect the strain on the transmission. It would be a different force against the engine than say driving into a strong headwind in so much as the restriction(dragging brake) is indirectly connected to the engine through the drive train.... something has to take the punishment of the dragging brake and the logical connection is the transmission. You would think that something else between the dragging brake and the transmission would break before that but since the brake is just dragging and not locked up... than the wear to the clutches in your trans would be of a cummulative nature wearing more quickly than normal. (other parts would also be slightly affected). It is the same idea as premature tranny wear in an auto truck transmission used for pulling a trailer, but a bit different since the dragging brake is putting a clamp on your drivetrain directly and prolonged the whole time you are driving, whereas a trailer being pulled has wheels and the most strain is only present when taking off from a start until you get the unit rolling. I know what you are saying though, it is probably not really an issue.


1. nope same size tires
2.Could still be a possibility, but I am starting to think this diff temp is normal and I was just over-reacting cause I had never got out to feel the diff before so have never realized the actual temperature that a diff runs at. I am no longer concerned about the diff temp. unless someone tells me otherwise.
3.Yep, radiator and cooling system is fine and with the new axle the engine seems to be running at a more steady and slightly cooler temp. (like two needle's widths). You are right I am getting nit picky about the temperature and where it runs, I was mostly concerned about how it would intermitantly fluctuate, before I swapped this axle.. That seems to have worked itself out and whether it has burped out an air bubble OR is a result of not having some thing like the axle binding the drivetrain and straining the engine. All air is burped out of it. I happen to think the drop in engine temp IS due to the axle change, but I could be imagining it wrong.

Now, I am going to bed and taking a break from this for awhile to recouperate.