83 240D - 2nd gear rough when cold - PeachParts Mercedes-Benz Forum

DieselAddict · #1 12-12-2003, 02:44 PM

I've had my manual 240D for 4 months and lately with the cold whether I've been experiencing a somewhat rough 1-2 shift when the car is cold if I shift at normal speed. If I shift slow or after the car is warmed up it's smooth, but still not as super smooth as the other gears. I've drained what appeared to be old ATF out of the transmission and replaced with Mobil 1 0W-40 with no improvement. Do I have a bad synchro? How long can the transmission last with this condition?

JimSmith · #2 12-12-2003, 03:20 PM

DieselAddict,

You will find a number of posts on the subject of manual transmission lubricant selection by using the search function. I am not sure the lubricant you have selected is going to make the low temperature shifting of the transmission any better. Read the old posts and pick something intended to improve low temperature action.

As for the damage that exists, if you continue to aggravate the weak synchro it will continue to degrade. If you take it a little easy when the car is cold, use a suitable lubricant and keep it clean, and don't aggravate it further, there is no reason the transmission needs to get any worse. The synchronizers only get loaded during shifts, so driving in a given gear should not speed up their demise.

Good luck, Jim

DieselAddict · #3 12-12-2003, 06:11 PM

Hi Jim,

I did do a search on manual transmission fluids prior to replacing mine. From my conclusion there are only 3 options: ATF, motor oil and Redline MTF. Some said today's ATF is too different from the recommended type A. I couldn't find Redline MTF in any store. As far as motor oil is concerned I remember Larry Bible saying he's had good results with 10W-30. I opted for 0W-40 instead because of its faster flow in cold temps. What do you use?

What you say about taking it easy when cold makes sense and I'll do that.

I was also wondering if this problem is common or if it's due to previous owner abuse.

JimSmith · #4 12-13-2003, 12:10 AM

DieselAddict,

I think the first to second synchro works the hardest (typically the greatest drive ratio difference is between first and second gears), and therefore is easiest to abuse. So, there is a greater tendency for this gear change to develop a clunk. As you have noticed, giving a little extra time can reduce the clunking quite a bit. So, knowing the clunk cannot be good, I think the best bet is to avoid it with technique as well as with the best lubricant you can find.

I use RedLine MTL. RedLine also makes a synthetic ATF they recommend for manual transmissions that, like yours, call for an ATF. Try going to www.jegs.com or another internet reseller if you can't find a local dealer. The D4 ATF is specifically touted as the best product they make for low temperature shifting with manual transmissions. I have never tried it as it is pretty new and the last time I bought MTL I bought enough to change all my cars. I still have a couple to take care of, and maybe I will try the D4 ATF next time.

Good luck, and I hope this helps. Jim

william rogers · #5 12-13-2003, 02:42 AM

My 115 240 had to be shifted slowly into second till I replaced both the clucth master cylinder and slave cylinder ,it now shift smoothly in all gears..........

William Rogers.......

DieselAddict · #6 12-24-2003, 01:42 PM

Well I found a local Redline dealer and I'm picking up a couple quarts of Redline MTL this afternoon. I'm not expecting miracles but I decided to give it a try. This will be the 3rd time I'm replacing my transmission fluid in the last 2 months.

Hopefully this is the last time for quite some time. The first time I did regular 10W-40, and then synthetic 0W-40. I'll report the results when I get this MTL in there.

leathermang · #7 12-24-2003, 03:42 PM

Technical note on the REDLINE ATF... it will do NOTHING in the trunk of your car.. I have tried that for three months...no change in my 2-3 shifting clunk.... so put it INTO the transmission....
Wanted you to have the benefit of knowing the results of my experimental testing.

DieselAddict · #8 12-24-2003, 05:41 PM

Leathermang, thanks for the tip. I put the fluid in my closet, and so far I haven't seen any noticable improvement and now I know why.

Will put it in my transmission as soon as it stops raining/snowing here.

Stevo · #9 12-24-2003, 09:29 PM

RedLine MTL has worked well for me, no more gringing going into 2nd unless I shift really fast. There was a noticable improvement and I was using Amsoil ATF.

DieselAddict · #10 12-30-2003, 02:41 AM

Well I put the MTL in the transmission last night and today I drove it. No change as I expected, but after reading the extensive write-up by Redline I believe it's probably the best stuff for the transmission and will keep using it.

BTW, I don't hear any grinding when shifting from 1st to 2nd when cold, only the shifter vibrates for a split second and doesn't go in as smoothly as into the other gears. But if I pause between 1st and 2nd or go into neutral first, it's smooth. I need to repair my leaking rear brake calipers and so I'll bleed the clutch system afterward and see if it helps. If anyone has any other suggestions, I'd appreciate them.