Transmission Flares - PeachParts Mercedes-Benz Forum

Opokhna · #1 05-10-2013, 12:56 PM

Hey guys, I have noticed a very minor flare in my 1995 e300d transmission when I bought it. The transmission has 195,000 miles, I do not know any history on the car other than some minor stuff I could dig up myself. I just did a transmission service on the car, I replace fluid and the torque converter fluid too, new pan gasket and new filter. The fluid itself looked like used motor oil, it was very dark brown. With the new fluid I noticed the flare more between 2nd and 3rd and now a little one between 3rd and 4th. I have looked into the K1 spring kit but they only seem to work on the 2nd to 3rd shifts, also there seems to be a vacuum going there that can create a wrong vacuum I guess which can make that happen with the shifts. If anyone can help me with how to diagnose a vacuum leak or figure out the vacuum that would be great and I would like to hear opinions on wheather or not I should be looking into a new transmission in the near future.

Chris W. · #2 05-10-2013, 01:20 PM

My '95 E300 has 393K with the original trans. I have had a 2-3 flare for at least the last 100K. I changed the K1 spring, which firmed the shift itself, but did not change the flare before the shift. I am able to get shifts without any flare by backing off the throttle just before the shift, in effect my backing off causes the shift to occur.

I don't think there is any cheap solution to this, if a fluid change doesn't help. However you now know that a flare is not a death sentence for the trans, and if you drive with care you should have plenty more miles in the trans. I fully expect to get many more miles out of mine, knock wood! BTW I'm running Amsoil synthetic trans fluid, FWIW.

Rgds,
Chris W.
'95 E300D, 393k, oil change scheduled for this weekend.

Diesel911 · #3 05-10-2013, 02:33 PM

My own thoughts are that you should check the Vacuum and the pressures (on mine there is an operating pressure and a Modulted pressure). If that is correct and you still have the problem the Spring Kit is the option left excluding rebuilding the Transmission.

That being said other than checking the Vacuum I have not done the above to mine so I have limited experience.

When I first got the Car and was new to the form I had a bad 3-4 Flare. Some people in the Forum recommended Lucas Transmission Sealer Conditioner (I also had a front Seal leak).
So at My next Fluid/Fitler change I added some and it reduced the leak and reduced about 75% of the 3-4 Flaring issue.

I also have a slight 2-3 Flare but that seems not to have changed much.

The Lucas stuff was slightly pink and otherwise reminded Me of STP. I it is similar it raises the Viscosity of the ATF and that would reduce leaks and increase pressure from the Pumps. So I am guessing that that is how it works.

A lot of Members also say no one should be using any sort of Addatives.

Transmission Vacuum and adjustments
Mercedes-Benz Transmission, Steve Brotherton, ImportCar, February 2002

Walkenvol · #4 05-10-2013, 03:34 PM

K1 spring is less than $10 from the dealer and takes about 2 minutes to change out when doing a tranny fluid and filter - sort of a no brainer to me if your not confident the spring has been recently changed in your tranny. Some folks have tried the entire tranny spring kit wth good results also, including the B2 spring. Some of the low $ / low labor minor tranny replacement springs strike me as preventative maint work on an older MB tranny, especially one showing signs of problems.

Opokhna · #5 05-10-2013, 06:07 PM

Quote:

Originally Posted by Chris W.

My '95 E300 has 393K with the original trans. I have had a 2-3 flare for at least the last 100K. I changed the K1 spring, which firmed the shift itself, but did not change the flare before the shift. I am able to get shifts without any flare by backing off the throttle just before the shift, in effect my backing off causes the shift to occur.

I don't think there is any cheap solution to this, if a fluid change doesn't help. However you now know that a flare is not a death sentence for the trans, and if you drive with care you should have plenty more miles in the trans. I fully expect to get many more miles out of mine, knock wood! BTW I'm running redline synthetic trans fluid, FWIW.

Rgds,
Chris W.
'95 E300D, 393k, oil change scheduled for this weekend.

That is nice to know that conservatively driving, it will still go a while. I just use the Castrol ATF I got from Mercedes.

Quote:

My own thoughts are that you should check the Vacuum and the pressures (on mine there is an operating pressure and a Modulted pressure). If that is correct and you still have the problem the Spring Kit is the option left excluding rebuilding the Transmission.

That being said other than checking the Vacuum I have not done the above to mine so I have limited experience.

When I first got the Car and was new to the form I had a bad 3-4 Flare. Some people in the Forum recommended Lucas Transmission Sealer Conditioner (I also had a front Seal leak).
So at My next Fluid/Fitler change I added some and it reduced the leak and reduced about 75% of the 3-4 Flaring issue.

I also have a slight 2-3 Flare but that seems not to have changed much.

The Lucas stuff was slightly pink and otherwise reminded Me of STP. I it is similar it raises the Viscosity of the ATF and that would reduce leaks and increase pressure from the Pumps. So I am guessing that that is how it works.

A lot of Members also say no one should be using any sort of Addatives.

Transmission Vacuum and adjustments

Thank you for the website, I will try to figure it out this weekend.

Quote:

K1 spring is less than $10 from the dealer and takes about 2 minutes to change out when doing a tranny fluid and filter - sort of a no brainer to me if your not confident the spring has been recently changed in your tranny. Some folks have tried the entire tranny spring kit wth good results also, including the B2 spring. Some of the low $ / low labor minor tranny replacement springs strike me as preventative maint work on an older MB tranny, especially one showing signs of problems.

I should have done it when I changed my fluid the first time, but after I correct the vacuum and pressures I will go for the kit route either way.

benedict · #6 05-10-2013, 07:25 PM

Quote:

Originally Posted by Chris W.

My '95 E300 has 393K with the original trans. I have had a 2-3 flare for at least the last 100K. I changed the K1 spring, which firmed the shift itself, but did not change the flare before the shift. I am able to get shifts without any flare by backing off the throttle just before the shift, in effect my backing off causes the shift to

I do the exact same thing by backing off accelerator. Disappointing thing for me is mine still flares from 2nd to 3rd after a full rebuild! Changing the seals and friction discs during a rebuild obviously isn't enough - tolerances need to be checked and set back to factory but most transmission places don't go this far.

benedict · #7 05-10-2013, 07:49 PM

The K1 spring is a good suggestion, i did it and it fixed the 2-3 flare but it also hardened up the downshift of this 2-3 change, kind of a thump developed at low speeds. It was a short lived repair for me as I lost reverse about 10,000 miles later.

It would be really good to know what exactly wears to create the 2-3 flare in these 722.4 box's.

I telephoned 3 places transmission shops in my city and emailed at least three in the US (peterschmid and sun valley)but no one gave a definite answer which I can understand as it is their speciality.