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1980 300D
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27 Posts
Discussion Starter #1
I'm new to Mercedes and even newer to diesel, so please bear with me.

I just purchased a fixer-upper 1980 300D with 362,000 miles. The transmission seems to shift fine (a little rough at times)but that's to be expected, problem is, it will shift into 2nd around 20mph and into 3rd around 30mph and will just continue to rev higher no matter how fast you go. Is this normal??
 

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2008 PT, 1998 neon--1965 VW 1200
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2,533 Posts
the post is a bit vague--

are you pushing the kickdown switch and starting in first, or are you starting in second?

these transmissions start in second unless forced into 1st by the lever or the kickdown switch(floor it, youll feel it)

if you are pushing the button under the pedal or pulling it down into 1, then try jiggling the shift knob, my car sometimes gets stuck in third and i just have to bump the knob and all is fine!

good luck![:)]
 

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Premium Member
W-1-2-3 Go!
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16,161 Posts
Hi and welcome, congrats on your "new" car [:p]

Maybe you haven't seen these articles yet:

http://mercedesdismantlers.com//diesel_vacuum_system#Diesel%20Vacuum%20System%20Troubleshooting

Obviously it's not normal. The reason iNeon mentioned the kickdown is if it's activated, the engine will race (rev higher) and shift much later (like the switch is stuck).

First, I'd check to make sure you have enough ATF in there. If it's brown or smells bad, you have to replenish your ATF with new fluid. If it's bright red and doesn't smell, it's good.

Second, check that the carpetting doesn't interfere with the pedal and kickdown switch (behind it). If you can't see one, chances are it's hidden behind the carpetting. Clear it and give it a test to see if it makes a difference.

Once you've checked these two, make sure your transmission is properly adjusted. The website above should help you, as well as this:

http://mercedesdismantlers.com//722.3and722.416_transmission_adjustments.html#722.3%20and%20722.416%20transmission%20adjustments

These transmissions are controlled mainly by vacuum, so it's quite different compared to similar cars of same year. With that high mileage, I would also give it a good run down of everything to be safe. If you want to know if your transmission is rebuilt, check the torque converter. If it's colored, it's rebuilt. My mechanic confirmed that mine is rebuilt. My torque converter was light blue.
 

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1980 300D
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27 Posts
Discussion Starter #4
Sorry about being vague and thanks for the replies.

This is the first I've heard of the kickdown switch, so i'll look into it.

I will generally just take off with the trans in D. When "putting the pedal to the metal" at just about any speed, no gear shift is noticed. Will just get to speed in it's own sweet time. It will only downshift if done manually.

I just thought it odd that I had used up all gears by 30mph.

The exhaust is also bad, will this make a difference due to loss of back pressure??
 
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