Transmission Flush Problem

[adsm08]

Cool, thanks. What's bg?

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http://www.bgprod.com/home.html

 

[Muscleford]

Is a trans flush an approved maintenance procedure by Ford? The flush horror stories scare me. What is the recommended trans fluid maintenance schedule per Ford?

 

[adsm08]

Is a trans flush an approved maintenance procedure by Ford? The flush horror stories scare me. What is the recommended trans fluid maintenance schedule per Ford?

It is. For vehicles using Mercon V (all RBVs) the recommended interval is 3 years or 30K miles.

For vehicles using LV fluid it is 30K severe duty, 50K regular duty.

The "horror stories" are from vehicles that are allowed to go over by extreme amounts (ex +90,000 miles on the original fluid). In these cases deposits in the trans that get flushed out are covering up things that would otherwise be an issue.

Kinda the same way that changing to synthetic oil late in an engine's life can cause oil leaks by cleaning away deposits that are blocking spots what would already be leaking.



Keeping fresh fluid in the trans will help prevent these problems, not cause them.

 

[Tedybear]

It is really hard to "backflush" a transmission. You would have to fill it completely full and then force fluid to go through it backwards. It wouldn't work very well, especially when it is running and trying to pump it the other way.

Most flushes use the transmissions pump, they unhook a cooler line and as the transmission pumps fluid out it lets new fluid is let in.

What is a problem is a neglected or worn transmission can depend on the clutch fibers floating around in the transmission fluid to get traction. Change the fluid and you have a slip-o-matic because there is no clutch fibers to help it along. Then things depend on heat to swell and grab before eventually there is nothing.

Generally if a trans dies after a flush its days were numbered anyway, only now the car owner has someone to "blame."

Not trying to be difficult. The way the local shop attempted to rope me in on this service? Was to 'brag' about how great a job their "house flush" machine did by reverse flushing all the crap out, and how it would "renew" a filter by back flushing the crud out of it and then it would get sucked up by their wonderful 'Machine', and it would renew/refresh the fluid as well.

For the record? I've never recommended a transmission "Flush", and probably never will. I'm old school. Drop the pan and LOOK at the condition! If the converter has a plug? Pull it and drain the converter as well! Is the filter full of metal trash? Is the magnet covered in metal "hair" to the point of excess? Or does it have just a light coating of gray flake, which is normal wear and tear.

Put another way. Flush Flush Flush...and most places ignore the filter. That's the same as taking a shower and putting on the same dirty clothes.

S-

 

[john93rangerstx]

just so u know some cars u cant change the filter with out splitting the case so flushing the only way to get the crap out

 

[wildbill23c]

This happens a lot on older higher mileage transmissions. The old fluid had enough particles in it to give the transmission enough friction to operate correctly. The new fluid is lacking all those particles and the transmissions internal clutch packs are already worn so changing the fluid reduced the friction material for the clutch packs to continue to work.

So as a result you need a transmission rebuild. This is why transmission flushes are not recommended for older transmissions with high mileage and lack of previous service.

 

[PirateB]

Best method on a high milage trans is to drain/fill a quart or two at a time until its full of new fluid. I usually do 2qt drain/refill every 500 miles until im satisfied with the color of the fluid I'm draining. Never had a problem.

The one time I did a full drain/refill and filter trans slipped pretty bad on my gfs car. I drained out half the new fluid and put half the old fluid back in. That was 50k miles ago...

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[85_Ranger4x4]

Not trying to be difficult. The way the local shop attempted to rope me in on this service? Was to 'brag' about how great a job their "house flush" machine did by reverse flushing all the crap out, and how it would "renew" a filter by back flushing the crud out of it and then it would get sucked up by their wonderful 'Machine', and it would renew/refresh the fluid as well.

They fed you a line that should scare anyone, it would be the equivalent of trying to back flush your engine. You would have to fill the crankcase full before anything would come out the valve cover. The same would apply to an automatic trans, the thing is not full to the brim with fluid and since they can't really force it through the engine has to be running and they can't pump it against the transmission pump...

Unless they were backflushing the coolers...

I change the filter myself and have mine flushed (no converter plug) I just did it a couple months ago and the truck has 104k miles on it and still shifts great. It had just been done when I got it at 25k and I did it at 60k too.

 

[Tedybear]

They fed you a line that should scare anyone, it would be the equivalent of trying to back flush your engine. You would have to fill the crankcase full before anything would come out the valve cover. The same would apply to an automatic trans, the thing is not full to the brim with fluid and since they can't really force it through the engine has to be running and they can't pump it against the transmission pump...

Unless they were backflushing the coolers...

I change the filter myself and have mine flushed (no converter plug) I just did it a couple months ago and the truck has 104k miles on it and still shifts great. It had just been done when I got it at 25k and I did it at 60k too.

Well it was a Valvoscream shop that tried to talk me into it. (our company cars and trucks hold a national account with them for maintenance)

Soon as they said "BackFlush" and "Fluid Renew"? hummm...No. Drop the pan, change the filter and refill 'when' it's scheduled. It's been 20 years sense I worked in a repair shop as a tech. So my ASE certs are all expired and the memory is about as fuzzy as trying to watch High Def on a 1960 B&W telly.

S-

 

[adsm08]

Trans filters are kinda pointless. Most new transmissions don't even have them anymore.

Thing about the filter is this. It doesn't catch most of the stuff that does damage. The biggest reason to flush the trans is to get all the little particles of friction material that float around in the fluid out. The filter doesn't really pick that stuff up. The magnet does to a degree, but it is not perfect.

The things the filter catches are bigger pieces, like pieces of transmission.

BG has the best transmission flusher hands down. Uses the trans pump most of the time, has an electric pump to help when needed, but it can't put in more than it takes out. We have a Motorvac unit where I work and it is JUNK.

It works well in dipstick mode, but dipstick flushes are for dipsticks. I don't fully trust that the cooler mode does it's job correctly, just seems to me that the fluid coming out at the end should be brighter. I have also seen it over fill transmissions. First time the one guy tried to use it he got 4 quarts of new fluid in, then ended up, in very short order, with 6 quarts of new fluid on his floor out the trans overflow vent.

I have also sold (under used car warranty thankfully) a converter seal, only to get the trans out and find that the stupid machine over filled it and the stupid oil changer didn't check the fluid level when he was done. The fluid coming out the bell was coming from the over flow line that clips into the top of the bell housing.

Then on the other side of it Thursday the stupid thing left me 3 quarts short.

I NEVER had those problems with a BG machine.


Then there were the Total Trans Service machines. You take the pan and filter off, hook into the pickup, and it pushes fluid through all the passages in the trans, until it comes out bright red. Then you put a new filter and gasket on, fill it, and go.