W126 Transmission Acting Up in Reverse !

After startup and a little warm up time elapse, I put shifter in to "R" position, Nothing happen! No sign of gear engaging and will not creep
backwards. Until I step on the gas pedal a little, suddenly the gear engaged "reluctantly" and the car started to backup! All forward gears work satisfactory.
Not too long ago (about 1500 kms) I replaced the tranny fluid, Dextron 3 and filter + seal. There was some fine sediment "sludge" in the sump and clean it up before putting it back. Didn't drain the converter though. Have I done anything wrong here? This 1990 560 SEL has 200k kms on it.
What is going on here, tranny or electrical problems? All comments and suggestions are welcome.
...ricardo
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Double check your fluid level... car must be running and at operating temperature when checking... on flat level area. It is most likely to be low on fluid when you experience this kind of problem.
Otherwise, it is a sign of your internal seals are shot and requires a rebuild.
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I have checked the fluid level, it is between the low and high markers at normal operating temp. and car leveled. <...sigh...> Could this condition deteriorate further? Also, are the seals replacement doable with the sump removed? Anyway to verify that the seal is not holding up? Am hoping to avoid that rebuilding the transmission, if possible.
I called the dealership and service advisor said something about valve body maybe getting clogged on this 722.3 tranny? He also mentioned about hooking up to a computer to find shift points? Advisor also doubtful if the clutch and bands has anything to do with the present problem. Is there anything that I should be doing before throwing up my hands? What about those flushing equipment used in some shops?
Tiger, thank you for your input. Appreciate it.
...ricardo
Tiger wrote:

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The seals I am talking about it for clutch packs... all internals... which requires rebuild.
Are you sure your forward gear has no slightest hint of abnormality? The reason I asked because activating reverse gearing also activate one of the forward gearing... so if that forward gearing is activated during drive, you might notice something too.
You can buy the service manual for around $18 at http://www.txchange.com/atsg.htm and several other places.
The service rep is also correct on possibility of valve body problem.. the reasoning is over time, there is a varnish coat of old ATF that helps seals the valves... and when you changed the fluid with something pretty high detergent, it washes it off and boom... problem.
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Guess nothing last forever, eh? Just unfortunate that it did not last as long as I thought despite the care I put in.
As for the forward gears, they are not "perfect". No major flare up during gear changes. I can feel it during gear changes say 2-3 and much smoother at 3-4. Also, the engine rpm does "flare up" slightly. Thought that is normally. Does that mean the gear changes too soon or too late? I have read somewhere that some experience "silkily" smoother gear changes and only notice the change via the tachometer! Wow, that is some tune-up. Are there anything one should look out or perform maintenance work besides regular fluid and filter changes to ensure "longer" live on tranny? I don't screech the tire to take off.
Is Castrol Dextron 3 contain high detergent? What would you use? Any recommendations? Thanks for the link to txchange.com/atsg.htm and the inputs.
...ricardo
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When I asked what ATF to use in my 380SE, there were a few different accounts from people on the mbcoupes forum (mbcoupes.com) saying they had tranny problems, tried mobil 1 ATF, and the problems went away. I've had mobil 1 ATF in my tranny for a good while now (but I made sure to empty the torque convertor too, and I cleaned the tranny pan with Wurth brake/parts cleaner). Richard

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Thanks for the input. I remember when I seek advice from the dealership's service advisor, he approves the Castrol Dextron 3, Mercon fluid. Not knowing of any other compatible and better ATFs, I went ahead. Now, I got choices, thanks to you marlinspike and Tiger. Oh, care to share how you locate the drain plug on the convertor? ;-))
...ricardo
marlinspike wrote:

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Unless you want to pull out your radiator so that you can crank the engine over by hand, finding the drain plug in the convertor is a bear. Here's what I did.
First, take off the cross brace that's under the torque convertor. Make sure to get new bolts from your dealership for this. While you are under the car, looking in that area at the bottom of the torque convertor where the torque convertor drain plug would be (it's hard to explain) have somebody turn the engine from the power steering pump pulley (I believe it's a 24mm bolt, but it might be 27). This will only let them do one cycle. If you don't yet see the drain plug, get out from under the car, touch the starter (i.e. don't start the car but just break the combustion pressure), then get back under and have the person turn from the power steering pulley again. Eventually you'll see it. Richard

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Hi marlinspike,
Thanks for the attempt to explain the drain plug location and your procedure. The last attempt I did not find the drain plug. I was looking at the wrong place!! <grin> Got someone to help turn the engine over at the crankshaft with spark plugs removed and I was looking up at the torque convertor locating hole that has a plastic cap on it!!!??? Now I know to look at the convex surface of the bell housing where there is a 'L' shape opening in the casting. Way forward of where I was trying to find! Thanks to the "manual" 722.3.pdf.
There are some TSB issued on the tranny since, any idea where one can get hold of one? Nothing from the dealership.
Regards,
...ricardo
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It has a plastic cap on it? Mine doesn't. Mine has just an opening.

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I use Valvoline ATF... they are better than Mobil ATF (not the synthetic one)... Tranny shift very smooth with it and Valvoline specifically formulated it so it doesn't ruin your old tranny.
That page you posted also discussed that flare up symtom... the K1.
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Ricardo,
I had the same thing happen to me with my 95 S320. I bought the car used then changed all the fluids and filters "just in case". A few days after the tranny fluid change I experienced the same problem you describe. I figure if it needs a rebuild, I'll do it if or when the forward gears are affected. I don't see the sense in rebuilding the reverse section only to have to pay labor to have it removed again in the future!
All the best, Alvin

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Alvin,
Thanks for the tip! As I mentioned in reply to Tiger, whether the condition can quickly deteriorate further and render the car unusable. I hope not and don't think so. I would continue to use it like you said. Its' just annoying to have to do a little foot works to minimise the "jerk" during engagement of the Reverse gear. Like left foot on the brake pedal and right foot gassing just a little to engage! :-))
I was hoping that it could be of something "smaller" things that I may have overlooked. Anybody has a 722.3 transmission manual for sale or could point me to purchase one.
Thank you and have a pleasant day!
...ricardo
Alvin wrote:

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Ricardo,
I forgot to include in my post that this problem started about 14 months ago. Just be careful parking on too much of a downward incline. Mine slips if you try to back it up a steep incline. Fancy foot work is now a routine and I'll wait till it dies since a local rebuilder said any further damage would be to the internal parts that need to be replaced during a rebuild anyway.....
All the best, Alvin

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Alvin,
Thanks for the heads up. I didn't thought about it. I need to back up to my inclined driveway on to the roadway, always! Guess that could have contributed to the early "demise" of the friction material :-))
Found a very helpful site, http://transmission.articles.mbz.org/ It may be of interest to you. I read the file, 722.3.pdf, a 7.2MB file of 180 pages! It's a scanned pages and thus are not that great in text and graphics. Better than nothing! I gather that the item, Multi-pack brake band B3 has worn out. It also tells me that activation of this B3 is responsible for putting the gear sets into reverse! Interesting! The next question is, How? :-)) ...more reading!
In the meantime, I need to drive and park with "care" !!;-))
Good day!
...ricardo
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Mmm... where did you find the manual? I didn't see it... There is an interesting section... adapting a 5 speed tranny to older cars... but zero info about it...
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To marlinspike and Tiger,
Thanks for sharing the preference on ATF. I will seriously consider it the next change! By the way is there a better way of locating the drain plug on the convertor? Hmmm, I always seem to miss this one. :-))
Tiger, as regards to the web page to the 722.3.pdf file and "adapting a 5 speed tranny...), its here http://transmission.articles.mbz.org/5spd/ and the pdf file can be found at the main page (remove ...5spd/ )lower left corner. Need to scroll down the page to see.
Oh, by the way, today I drove the car and it did not exhibit the problem. Maybe only once. (meaning slow in engaging Reverse gear) So, this problem is intermittent, meaning its nearing to becoming a real problem at worst or maybe it will ...go away! <grin>
...ricardo
Tiger wrote:

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