vacuum leak, tranny flaring..part 2 - PeachParts Mercedes-Benz Forum

JamesDean · #1 10-24-2005, 11:11 AM

hey sorry for the new thread but my old one had been deleted, dont know why. the links in my emails goto a thread in the Parts section.

Backstory:
I had a vacuum leak at the bleed-off valve on the IP. I replaced the bleed-off valve, vaccuum is 15" at the tranny port. The modulator holds 23" for better than 5minutes.

Changed the tranny fluid with Mobil 1 Synth and added some stop-leak (I have a front seal leak) The pan gasget and tranny filter was also changed.

1-2 shift is good
2-3 shift has terrible flaring. Anywhere between 500rpm and 2000rpms.
3-4 is fine.

I have no adjusted the modulator since the fluid change, but, before I changed it I adjusted it 5 notches clockwise.

Did I adjust the wrong way? Is my modulator shot (its the Original and the car is an 82-300SD)

Thanks Guys,

Kris

rg2098 · #2 10-24-2005, 11:40 AM

I can't remember which way to adjust it, but if it holds vac then the modulator is good.

1983/300CD · #3 10-24-2005, 12:19 PM

Sounds like a K1 spring issue? Do a search for it. I sure would like to see a DIY guide on that (whoever does it first).

Old300D · #4 10-24-2005, 01:10 PM

Definitely sounds like a K1 spring issue. My transmission is doing a similar thing, but it's not that bad. I spent this weekend adjusting the throttle linkage, the bowden cable and verifying the vacuum. I've been slowly getting the fluid up to the right level, and after adding a pint of Trans-X, I may only have one more pint of fluid to get it to the dipstick marks. My shifts are quite firm except for the 2-3, so that points to the K1 spring. Search in the archives for that spring kit, I've not got the number handy.

Pete Burton · #5 10-24-2005, 02:08 PM

No harm in trying the K1 kit, it's quite inexpensive. However, neither that kit, Mobil 1, trans-x, new modulator or finally rebuilt valve body was able to help old Blue shift properly. I removed and rebuilt the trans this summer. One of the K1 discs was almost completely absent of friction material. The B3 plates were evenly but nearly all worn out. Clutch pack seals were rock hard, teflon seals had significant metallic impregnation, brake bands loose, front pump bushing shot (of course, that's why your front seal leaks too), etc.etc.

On the upside, because I used 2 transmissions and stopped running this one before it self destructed, I reused the valve body and torque converter and spent about $300 total in rebuilding it. It was really a lot of fun, since I could just drive my old pickup while I took my time. Good luck!

JamesDean · #6 10-24-2005, 02:47 PM

thanks guys, can anyone point me in the direction of this K1 spring kit? Perhaps some pointers or anything like that...thankx....nowi have to drain the tranny and waste all that $80 of Synth..

kris

Hit Man X · #7 10-24-2005, 02:52 PM

Nah, it's on the side of the case... it's like swapping a larger servo into a 200-4R or a 4L60E/700R4.

Pete Burton · #8 10-24-2005, 02:53 PM

it's 126 270 44 77. about $11 at dealer. You'll only drain about 2 liters dropping the pan, and if you clean the drain pan, pull the plug first, you may be able to refilter that (but be careful).

Pete Burton · #9 10-24-2005, 02:56 PM

Quote:

Originally Posted by Hit Man X

Nah, it's on the side of the case... it's like swapping a larger servo into a 200-4R or a 4L60E/700R4.

The K1 kit replaces a few parts inside the valve body. You must remove the pan to access it, but it's not hard. Just keep everything a little cleaner than you possibly can

#10 10-24-2005, 03:28 PM

The modulator adjustment is counter clockwise to stop the flaring. First reset the five notches, then set it one notch at a time counter clockwise and see what the result is.

JamesDean · #11 10-24-2005, 03:34 PM

the flarring isnt consistant. It doesnt flare as badly every single time it shifts 2-3. One might be a slight flare of 50rpms others have gone to 2000rpms.

Ill try the modulator.

thanks

Pete Burton · #12 10-24-2005, 03:44 PM

I believe you want to turn the modulator adjustment CLOCKWISE to increase modulating pressure. This is also achieved by reducing vacuum, as the vacuum diaphram pulls the modulator plunger back against the spring when vacuum is applied.

Old300D · #13 10-24-2005, 04:10 PM

Quote:

Originally Posted by JamesDean

the flarring isnt consistant. It doesnt flare as badly every single time it shifts 2-3. One might be a slight flare of 50rpms others have gone to 2000rpms.

Ill try the modulator.

thanks

I'd like to add that adjusting the modulator adjusts all the shifts. If 1-2 is firm and 2-3 is soft, adjusting the modulator to eliminate flare will make the 1-2 really rough.

Hit Man X · #14 10-24-2005, 07:56 PM

Quote:

Originally Posted by Pete Burton

The K1 kit replaces a few parts inside the valve body. You must remove the pan to access it, but it's not hard. Just keep everything a little cleaner than you possibly can

Hrm... I must be thinking of the K2 kit, the one on the case

That's the one that should apply one of the bands.