tranny flush????

[jakemprater]

i know on autos if your over 100k dont change the fluid. but what about an M5OD? it has a new clutch (which shouldnt matter just throwing it in) and a small leak from the tailshaft housing. i am thinking about just draining it all putting in lucas and dex/mercIII and runnin with it. good idea or horrible idea? my truck has 225k on it. as far as i know its never been done b4.

 

[Evan's f250]

i think the whole over 100k thing is a myth, ive changed trans fluid at 131k and was just fine,shifted much better. it was on a 2000 grand prix. if your manual trans calls for the merc fluid i'd go for it and change it man.

 

[dustybumpers]

I put mobile 1 in my zf at 150,000. the truck now has 480,000, and the zf still shifts like new, and makes no noise.

 

[Skandocious]

You can and SHOULD change your oil on high mileage transmissions-- you just shouldn't FLUSH it. Flushing involves shooting pressurized fluid through the trans and it can break loose junk that was not causing problems before and is now clogging small passageways. Drain and refill is very safe to do.

 

[flareside_thunder]

I don't think a so-called "flush" can be done on a manual trans......but I agree with what Chris said about it breaking particles loose.

 

[Alvin in AZ]

I put mobile 1 in my zf at 150,000. the truck now has 480,000,
and the zf still shifts like new, and makes no noise.

Which Mobil-1?

Sounds like your ZF is in better shape than my 188k ZF.
But my ZF came out of a "company truck" tho.

Alvin in AZ

 

[dustybumpers]

straight 30 wht.it has held up well, I am the only owner/driver, guess that has helped it to survive

 

[70torino429]

I have my M50D out at 150K for a new clutch and I'll be changing the fluid.

 

[Alvin in AZ]

Redline MTL was recommend to me for my ZF and so bought 4 quarts.
I'll put it in when I put in the new gears, synchro hubs and bearings.
Last time I only swapped out the ZF's synchro rings as a test, found
out it's noisy in 3rd.

Alvin in AZ

 

[nighthawk285]

You can and SHOULD change your oil on high mileage transmissions-- you just shouldn't FLUSH it. Flushing involves shooting pressurized fluid through the trans and it can break loose junk that was not causing problems before and is now clogging small passageways. Drain and refill is very safe to do.

Not true.....flushing involves changing out the dirty fluid for clean fluid. Come on Chris, you're better than this. Any auto trans runs at at least 20lbs of pressure while its in park running idle....a flush machine only puts an extra 3-5lbs of pressure while it pushes out the old fluid and exchanges it for the new. Yes it can break loose junk, but if you have the kind of build-up where you're getting clogged passageways, you've on the verge of a tranny rebuild anyways. Yes drain and fill is safe to do BUT.....1 you only change out maybe 4 quarts of an up-to 12 quart system (fluid still lies in valve body, channels, TC, clutch areas) and 2....if there is any small buildup that could be especially damaging, you don't get that "extra pressure" to break it loose and get out before it really scars something up....

If you want to do a full trans service and do it right, run it, flush it, let it run for awhile to get everything into the filter, then drain and fill with a new filter. It's a little more expensive for the service, but it'll save your trans in the long run.

As far as a manual, yes service the thing! Come on, its just like doing an oil change. Parts wear, they leave behind material in the fluid, so the fluid needs to be changed to prevent faster wear.

 

[Skandocious]

Nick I've heard more than 1 horror story about healthy trans' needing rebuilds after getting a pressure flush. And you can most certainly get more than 4 quarts out with a drain and refill-- open the inspection grommet on the bellhousing and rotate the crank with a wrench until you see the drain plug in TC. The fluid from the TC and pan will account for MOST of the fluid. The extra couple quarts is the cooler + cooler lines is just a drop in the ocean of 16 quarts that these trans' take.

 

[nighthawk285]

wow, sounds like they were getting work done at some shoddy shops....and as far as the drain and fill I was just talking about the pan, as thats all most shops will do for that too, but I do agree, if you get it all out of the TC and the pan, you've got a lot of it, but then there's the problem of having an un-primed TC/oil pump when you start it all back up. So I do apologize for misunderstanding, but stand by my training/experience

 

[Skandocious]

wow, sounds like they were getting work done at some shoddy shops....and as far as the drain and fill I was just talking about the pan, as thats all most shops will do for that too, but I do agree, if you get it all out of the TC and the pan, you've got a lot of it, but then there's the problem of having an un-primed TC/oil pump when you start it all back up. So I do apologize for misunderstanding, but stand by my training/experience

There is a procedure for filling and properly priming the pump. You fill with ~5 quarts, start it and run it through all gears then turn it off. Fill with another ~5 quarts, run it through all gears and turn it off. ~5 more quarts, repeat again. Then you add quart my quart and check the level until it's full.

 

[nighthawk285]

There is a procedure for filling and properly priming the pump. You fill with ~5 quarts, start it and run it through all gears then turn it off. Fill with another ~5 quarts, run it through all gears and turn it off. ~5 more quarts, repeat again. Then you add quart my quart and check the level until it's full.

good to know

 

[Skandocious]

good to know

Let me clarify my previous post a bit-- by running through all gears I mean that you run the column shifter through every position. But your foot should be on the break and the truck should be completely stationary. You don't have to hit all the "gears"-- just all the shifter positions.

 

[nighthawk285]

yeah I figured that much but thanks for the clarification bud!