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1983 300TD, 115,000 miles. Anthracite Gray
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Discussion Starter #1
Here's a topic that has been discussed a lot on this and other forums. I've read dozens of threads on the topic, but I still lack a clear picture, so I thought I'd ask some direct questions an hope that somebody out there can give me direct answers.

I am the proud owner of an '83 300TD with 115,000 original miles. This car has a 722.3 transmission. It looks great and runs superbly. But over the last couple of days I've started to notice something that seemed a bit strange. I started counting gears and counted only three; that is, it only seems to shift twice.

Now, according to pages from service manuals I've seen here, I think this car should idle in 2nd gear, but downshift immediately to 1st when I depress the accelerator pedal, however slightly. In that case, I should notice 3 subsequent shifts (not counting the initial downshift). Is this correct? But I only count 2.

Anyway, I can't detect any downshift when I step on the accelerator pedal, on either the tachometer or by sound or feel. The car speeds up of course, but I don't sense it changing gears. Should I be able to feel it downshifting when I step on the pedal?

When I put the transmission in Low, where it ought to cover the first two gears, I don't detect any shifting at all. It seems to be in one gear the whole time, up to rpms as high as I dare rev it.


To me it feels like 1st gear is MIA. But I can't be sure because I have nothing to compare it to. At what speed should the 1-2 shift occur?


I've tried fiddling with the Bowden cable and it does what it's suppose to do: tightening it makes the car shift at higher rpms. But it doesn't get me my gear back.

By the way, I can floor it from a standing start and it still doesn't seem to downshift. There's no sign of a lower gear under any circumstances.

So what's going on with my tranny?

P.S. Had it checked out three days ago by an independent MB mechanic. I hadn't noticed this issue at that time, so I didn't have him try to solve it. But he checked the car out thoroughly and found it to be in good health; replaced a piece of fuel line, slight valve adjustment, new VC gasket, a couple of other little things. But he didn't mention, or adjust, anything about the transmission.

Thanks all.

Jim
 

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2001 Volvo V40
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2,954 Posts
If you put the transmission into L, the 1>2 shift will take place at the highest possible point, that is around 4400 rpm (also around the 1 shift mark on the speedometer).

The gas linkage is constructed so that you first actuate the bowden cable (and switchover valves of the EGR) and than the diesel pump. Under normal circumstances you would not feel the 2 > 1 downshift when you drive off. Have you tried accelerating with the accelerator pedal fully pressed? And with kickdown?

If it does not want to drive off in 1st gear, adjust the linkage according to specs. You also might want to check the working of the vacuum control valve.
 

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1983 300TD, 115,000 miles. Anthracite Gray
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163 Posts
Discussion Starter #3
Have you tried accelerating with the accelerator pedal fully pressed? And with kickdown?
I have tried it with the pedal pushed down, and on the floor. I can't detect any shifting then either.

I'm off to try again in L, to see if there's any shift at the I mark on the speedo.

Thanks for your help.

Jim
 

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1983 300TD, 115,000 miles. Anthracite Gray
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163 Posts
Discussion Starter #4
OK, back from a new trial. With the car in "L", there's no shift in or near the I mark on the speedometer.

In normal driving, the first shift is around 2500 rpm, which comes at about 25 mph. With it floored, the first shift comes at almost 40, and 3500 rpm.

I think I am indeed missing first gear.

Thanks,
Jim
 

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2001 Volvo V40
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2,954 Posts
The shift points with the accelerator pedal fully pressed should be:

1 > 2 = 22 mph
2 > 3 = 45 mph
3 > 4 = 72 mph

With kickdown the shift point for the 1 > 2 shift should be 25 mph.

If think your bowden cable is not adjusted properly. The first shift you describe is probably the 2 > 3 shift, that should be later. 3500 rpm is too low anyway, should be more like 4200–4500 rpm.

You do have the stock size tyres and stock rear differential?
 

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1983 300TD, 115,000 miles. Anthracite Gray
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163 Posts
Discussion Starter #6
You do have the stock size tyres and stock rear differential?
Yes, but my speedometer is not well calibrated; could this be related? According to tests I've run (measuring the time between two mile markers at various speeds) there seems to be about a 10 mph offset (it reads 80 when I'm going 70). I've been making this correction in the numbers I've been reporting in this thread.

Could my speedometer problem be related to the shifting problem?

I'll adjust the Bowden cable to shift later. The starting point had a tremendous amount of slack in the cable, and I removed a good bit of it, but it's still pretty loose. I wonder if they failed to tighten it back up after removing the valve cover.

Thanks very much.

Jim
 

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1983 300TD, 115,000 miles. Anthracite Gray
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163 Posts
Discussion Starter #7
OK, well here's a new wrinkle. The kickdown doesn't work. The switch is fine, but the pedal doesn't reach it. Could be the carpet I suppose, but after rearranging the carpet to get it out of the way, I'm still not able to make the pedal reach the switch.
 

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2001 Volvo V40
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2,954 Posts
Yes, but my speedometer is not well calibrated; could this be related? According to tests I've run (measuring the time between two mile markers at various speeds) there seems to be about a 10 mph offset (it reads 80 when I'm going 70). I've been making this correction in the numbers I've been reporting in this thread.
A GPS device can also tell you the offset.

Could my speedometer problem be related to the shifting problem?
No, the transmission doesn't take signals from the speedometer.

I'll adjust the Bowden cable to shift later. The starting point had a tremendous amount of slack in the cable, and I removed a good bit of it, but it's still pretty loose. I wonder if they failed to tighten it back up after removing the valve cover.
There should be no slack when the gas linkage is in idle position.

OK, well here's a new wrinkle. The kickdown doesn't work. The switch is fine, but the pedal doesn't reach it. Could be the carpet I suppose, but after rearranging the carpet to get it out of the way, I'm still not able to make the pedal reach the switch.
I'm guessing the gas linkage is not adjusted according to specs. Look it up in the FSM how to adjust it.
 
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