350SDL Transmission Woes - Page 5 - PeachParts Mercedes-Benz Forum

MongooseGA · #61 11-20-2016, 10:48 PM

Just to update, after doing the fluid and filter swap yesterday, the car is behaving better again (as expected, for now). I did go with the type F fluid again as I knew it worked, but also supplemented with 1/2 qt of Trans-X and 1/2 quart of Lucas. We'll see. I'm driving the car to VA on Wednesday for the holiday, and having a passenger bring my 300D back home from my parents' place as well. At least now I'll have a spare car (sort of like an escape pod!) to get around in if the 350 goes down.

ROLLGUY · #62 11-20-2016, 11:26 PM

One good thing about these engines, is that they will run on that used trans fluid (especially the barely used fluid you have been getting from the close together changes). A trip through a one micron filter bag, and the car will love it.

400Eric · #63 11-21-2016, 02:20 AM

Quote:

Originally Posted by MongooseGA

OK guys, the car's acting up again so tomorrow I'll be doing another fluid and filter change. I'll give it a shot with the 10 weight and trans-x, I think I have some Lucas left as well.

For the oil... I was told by John at BRM that the Type IV would have been best because it has NO detergents in it. Am I remembering this backwards? When you say 10 weight, any particular I should be looking for?

Sorry, I've been gone a short while. Other family members were still here though so this computer was still almost always on and my subscriptions tab is always open so it may look like I'm here even when I'm not.

Just straight 10 weight detergent oil. It won't be easy to find, so just take what you can get. Type IV trans fluid has loads of detergents in it. I think even the old type A has detergents in it. Detergents aren't your issue. Lack of line pressure is. We are trying to crutch that with thicker viscosity fluid/oil but now it looks like we missed the opportunity cause I wasn't here to answer your questions and now we have another load of thin trans fluid in there.

Quote:

Originally Posted by MongooseGA

Guys, I have a very stupid question to ask...

When I'm adjusting the modulator, does the car need to be running? I've been playing with it while the engine is off.

I did my two T-bars with the engine off. Just turn it all the way in till you get some resistance. Do this BEFORE you leave on your trip.

400Eric · #64 11-21-2016, 02:48 AM

Quote:

Originally Posted by ROLLGUY

One good thing about these engines, is that they will run on that used trans fluid (especially the barely used fluid you have been getting from the close together changes). A trip through a one micron filter bag, and the car will love it.

I know this to be true because I'm running Benzer8 on brand new straight type IV right out of a one gallon jug wedged under the hood as we speak to clean out the injectors. I'm feeding the lift pump straight from the jug!

I'm interested in burning old trans fluid. When you say "one micron filter bag", are you referring to a vacuum cleaner bag?

ROLLGUY · #65 11-21-2016, 12:01 PM

Quote:

Originally Posted by 400Eric

I know this to be true because I'm running Benzer8 on brand new straight type IV right out of a one gallon jug wedged under the hood as we speak to clean out the injectors. I'm feeding the lift pump straight from the jug!

I'm interested in burning old trans fluid. When you say "one micron filter bag", are you referring to a vacuum cleaner bag?

A filter bag that is commonly available for filtering veg oil. I was mistaken about the micron rating. I think a ten micron is the finest that can be had (I may still be mistaken). I use polyester cloth, and it works well. It is also much cheaper.

babymog · #66 11-21-2016, 01:16 PM

Why ten micron? Isn't the fuel filter on the car more like 5 or 6 micron?

I ALWAYS keep a fresh bottle of ATF in the car with a spare fuel filter, ... fill the filter with ATF when you change filters, primes quickly and starts SMOOTH. Also a good high-detergent injection cleaner with great pump lubricating qualities (most of the overused injector cleaners are solvents, and that's not good for your pump's internals' lubrication).

MongooseGA · #67 11-21-2016, 08:08 PM

Wow! Lots of good info in the last few posts.

I will give the modulator another twist tomorrow. When/if/should it start acting up again, I'll go with the 10 weight.

For now, she's still doing fine as of my driving this morning.

MongooseGA · #68 11-22-2016, 11:09 AM

OK so the morning started off really well, then ended on my return trip with the car kicking down into 3rd on the highway again.

*I realize this transmission will need to be rebuilt, it will get done, it's just not in the budget at the moment*

I will do one more fluid change today, with the 10 weight. If anyone would be able to point to specific brand, that'd be helpful. I guess what I'm a little confused about is whether it matters if it's 10W-30, 10w-40, etc, whatever.

MongooseGA · #69 11-22-2016, 11:59 AM

Pure Guard Non-California ND10 - Motor Oil | O'Reilly Auto Parts

Would this work?

400Eric · #70 11-22-2016, 12:32 PM

Straight 10 weight is good. That is what you want. I'm not so sure about the non-detergent part, but at this point it probably doesn't matter. Just remember to include the Lucas mucus and Trans-X again.

Just for grins I'd turn in that T-bar BEFORE this fluid/oil change so that you can evaluate the T-bar mod by itself. You have nothing to lose, you aren't going to hurt anything, and you might even be able to avoid another fluid change! (Which surely must be getting old by now!)

spock505 · #71 11-22-2016, 01:08 PM

Quote:

Originally Posted by MongooseGA

OK so the morning started off really well, then ended on my return trip with the car kicking down into 3rd on the highway again.

*I realize this transmission will need to be rebuilt, it will get done, it's just not in the budget at the moment*

I will do one more fluid change today, with the 10 weight. If anyone would be able to point to specific brand, that'd be helpful. I guess what I'm a little confused about is whether it matters if it's 10W-30, 10w-40, etc, whatever.

Have you tried replacing the K1,K2 pistons, this helped with my transmission issues no end.

If run dry you may have pulled up sludge (mine needed 3 changes before it stopped dis-coloring the fluid) which causes the pistons to move slowly or stick.

In addition, all three pistons have been upgraded by MB several times, it makes ordering a bit hit and miss but you should be okay.

Check out my K1 thread for details on the above, easy to do especially if you are changing out the ATF.

spock505 · #72 11-22-2016, 02:06 PM

Quote:

Originally Posted by 400Eric

Sorry, I've been gone a short while. Other family members were still here though so this computer was still almost always on and my subscriptions tab is always open so it may look like I'm here even when I'm not.

Just straight 10 weight detergent oil. It won't be easy to find, so just take what you can get. Type IV trans fluid has loads of detergents in it. I think even the old type A has detergents in it. Detergents aren't your issue. Lack of line pressure is. We are trying to crutch that with thicker viscosity fluid/oil but now it looks like we missed the opportunity cause I wasn't here to answer your questions and now we have another load of thin trans fluid in there.

I did my two T-bars with the engine off. Just turn it all the way in till you get some resistance. Do this BEFORE you leave on your trip.

Eric, have you gone down the road (excuse the pun) of checking vacuum pressure to the box?

In order to smooth things out after changing pistons (as above) i also opted for a softer modulator setting, this works well but I suspect the real fault is with the modulator itself.

Frank Reiner · #73 11-22-2016, 03:41 PM

Quote:

Originally Posted by MongooseGA

OK so the morning started off really well, then ended on my return trip with the car kicking down into 3rd on the highway again.

*I realize this transmission will need to be rebuilt, it will get done, it's just not in the budget at the moment*

Quote:

Originally Posted by spock505

Have you tried replacing the K1,K2 pistons, this helped with my transmission issues no end.

spocko:
Note that the OP is not ready to do a rebuild at this time; the K1 & K2 pistons are some of the last parts to be accessed during disassembly of the box. Perhaps you had the B1 & B2 pistons in mind; they are externally accessible.

Mongoose:
The recurrence of the gratuitous 4-3 downshift points yet again to low pressure. Suggest that you try the above recommendation to crank up the modulator pressure. That step is the easiest one to do, has no cost and very little labor involved. Repeated fluid changes are, at this point, a tactic of diminishing returns.

spock505 · #74 11-22-2016, 04:05 PM

Cheers Frank, I assumed it was the 722.x box but couldn't see a direct reference so perhaps not.

I did wonder after reading the passenger side modulator location, mines also on the passenger side but we have the steering wheel on the correct side

Frank Reiner · #75 11-22-2016, 05:54 PM

Quote:

Originally Posted by MongooseGA

OK so the morning started off really well, then ended on my return trip with the car kicking down into 3rd on the highway again.

OK goose, we need to ask: Have you cleaned out all those old Twinkie and Moon Pie wrappers that are floating around in your car? When you let them get piled up like that under the gas pedal they can trip the kickdown switch! Is that the cause of the 4-3 downshift?