And maybe I just need to overcome my torquing fears somehow....

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 178k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 75k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Do you guys tighten by feel or use a low-range torque wrench?

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 178k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 75k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I have always thought that it better to change both oil and filter and if I have to postpone that, I know that it was done from the ground up previously.

How did you arrive at that conclusion?

For all practical purposes, that is precisely what does happen with an automatic transmission. The pump is on the downstream side of the filter, but that is of no material consequence.

If I decide to repent of my current practice and do it the proper way, can I get by with a cheap (say $25) low-range torque wrench (looking at one at Harbor Freight, another on Amazon)? My hesitation is that I don't have a feel for the job (I'm sure most tighten the bolts by feel).

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 178k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 75k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Brother-in-law manages a transmission shop and he says by doing a partial flush you are renewing the additive package and that it is very beneficial. 100% replacement is not necessary.

Also knew a commercial fleet manager who every couple of years would take the lower rad hose off and then top up the rad with fresh fluid to renew the additive package and he never had any problems with his fleet of rads.

Me I drain my converter and drop the pan every couple of years, easy and reasonably inexpensive and I feel better about it all. I do the same partial drain and fills on the rad.

Thought that I should mention that I regularly "refresh" the power steering fluid with partial flushes, just to keep the additive package fresh.

Now the "blinker fluid", I am still on the old factory fill as I believe it is a lifetime fluid?

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1999 Mercedes E300TD daily driver sold at 238K miles 106K miles were mine, rust worm got it :-(
2006 Mercedes CDI new daily driver! 56,000 miles May 2016 now 85,625 Apr 2018 and Apr 2019 101,000 miles Apr 2020 109,875. March 2024 135,250, Dec 2024 145,000 miles

I start with a socket and 3/8" extension like a screwdriver, and my gloves are usually lubed with ATF. I use a hybrid head gasket-bowtie pattern like:

3 - 1 - 4
5 - 2 - 6

It must take a dozen rounds of snugging before it won't snug any further. Then I take a ratchet by its head and go a couple of three more rounds. I've never had a leak, I've never had to straighten a bent pan, and I've never had a gasket stick.

I use the same feel with Mopar and GM pans except those have 15 or more bolts. With those I start at a corner and tighten every third bolt until I've gone around a half dozen times. Then I start with the ratchet. I use RTV on the FWD Mopar because the ATF level is above one edge of the gasket. 220K miles on an original 41TE is a bigger achievement than 260K miles on a 722.3 The 41TE's starting to shudder when accelerating though

Sixto
87 300D

I don't think so - on a 722.1 valve body there's only one tiny exit hole that I can see. I haven't pulled my 722.3 valve body to bits yet but I guess it is the same story there.

The lubricating system in these automatic transmissions essentially seems to be a system of "splash" from what I can see - much like a differential. The only reason why these automatic transmissions use pumps that pressurise the fluid is to operate pistons to clamp certain parts of the sun and planet gear sets. The pumps aren't really used to help clean the ATF by passing it through a filter.

From what I can see there is no active filtering - like in an engine. The filter just tries to stop crud from entering the small oil passage ways in the valve body.

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

That's quite the collection of misconceptions. Serious misconceptions.

um, so, in your opinion, the filter is there for what purpose?
most hydraulic systems pull oil through a filter or pump through a filter...
I've always assumed the atf filter was akin to the engine's oil pickup screen, with a filter in it... no?

anyway, of all the trannys I've changed the oil and filter in, I've always found traces of stuff in the pan, and the filter is usually torn or pulled through in some places...
the cheapo plastic filter casing, (yes, even in the steel shroud) usually comes apart after pulling too much junk into it...
I ALWAYS change the filter when I drain the fluid... I've just seen too many filters that were pulled apart.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

That's what I've been waiting to hear....evidence of filter DETERIORATION. That's the best argument against my current practice (of extended filter intervals).

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 178k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 75k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Exactly. Fluid cannot get from the sump to the pump without passing through the filter first.

It is a shame that this subject as come up in a thread about a 722.3 - I've only taken a 722.118 to bits so the example I can show isn't 100% relevant to the transmission being discussed... However, I think they are all of the same ilk - so here goes. This is my understanding of the system.

As I said previously the only reason why hydraulic pump(s) are used in a conventional automatic transmission is to apply force / pressure to particular parts of a sun and planet gear system. (See wikipedia => Automatic transmission - Wikipedia, the free encyclopedia)

I think the filter in the transmission is behaving like a condom for the valve body. It is only protecting that part. I don't think the position of this filter is designed with the rest of the transmission in mind. I think the rest of the system that is NOT in direct contact with the operation of valve body is effectively told to go spit!

Here's a picture of a 722.118 filter fitted to the valve body - with the valve body fitted to the transmission. The hole in which the fluid flows through is covered with gauze.



Here's a picture of the valve body without the filter fitted...



...you can see that the fluid goes in through one hole in the valve body.

The fluid is sucked through the valve body by the front pump (this is sometimes called the primary pump). Only the input to the primary pump is filtered.

Here are some pictures that show the path through to the front pump and how the fluid under pressure gets supplied to the valve body.









Here are some pictures of the 722.118 valve body and how the plate that attaches to the main part of the transmission case covers both the input and output of the front pump.







I can't see how the fluid can get back out of valve body in a great enough volume to aid with the filtering of the whole transmission. I think I've found one tiny little hole that is connected to the "circuit" in the valve body - but I'm still trying to figure it all out...

I can't find any other connection from the front pump to the rest of the transmission. The only other connections that I have discovered on the front are for the oil cooler - and two test connections. I guess the direct connection from the front pump / oil cooler / valve body is the reason why people say you should make sure the flexible transmission oil cooler pipes are in tip top condition. Any crud from them could be pushed directly into the valve body - crud from them wouldn't be caught by the filter...

I don't understand why a hydraulic system like a valve body would want any great level of flow through it. The purpose of a hydraulic system is to transmit force. To be able to do that you need a good level of pressure.


So anyway that's why I think the filter is only there to protect the valve body and it has nothing else to do with the rest of the transmission. I can't see any evidence to the contrary.

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Actually mine is a 722.4....but I imagine they all operate similarly.

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 178k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 75k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

And when the filter is installed, fluid must pass through the filter enroute to said hole.


That is the only "input" that matters. And everything else that matters is downstream from the pump.

With that in mind, how can you possibly think that the filter protects only the valve body?