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Transmission Pan Drop vs. Flush: Which is Better?

Written by Charleen

Transmission Pan Drop vs. Flush: Which is Better?

John Baker|

It depends on what you want to accomplish. But, first of all, check your owner’s manual to see if your vehicle manufacturer recommends one instead of the other.

If you want to ensure removal of nearly all the old transmission fluid, then have your transmission flushed.

Here’s what we’ll cover:

What is a Transmission Flush?

The benefits are self-evident: all the old, dirty fluid is replaced with fresh, high-quality fluid. (And, as you can see in the image, new transmission fluid is preferable to old fluid). As a result, your transmission should run cooler and receive maximum protection against wear to clutches, gears and bearings. It should also shift consistently and crisply since the new fluid will provide the correct frictional properties (old fluid loses its frictional properties over time).

Not only that, but performing a flush helps clean the transmission. Sludge and other contaminants can accumulate in the fluid due to extreme heat breaking down the fluid. These contaminants circulate throughout the transmission before lodging in the filter. Before the filter can safely capture the contaminants, however, they can lodge in the narrow fluid passages inside the valve body, leading to poor shift quality.

The narrow fluid passages in the transmission valve body can easily clog with debris, reducing shift quality.

Performing a flush also allows you to use a flush additive to help clean the transmission and more effectively remove accumulated sludge and other contaminants.

Any downsides?

Potentially.

For one, it’s more expensive. And some people warn against performing a flush on a transmission using old, dirty fluid. The flushing procedure may direct the fluid in the opposite direction of normal flow, which may increase the risk of dislodging debris and causing it to settle somewhere it shouldn’t. Since the way each shop performs a flushing procedure varies, you can’t know for certain.

What is a transmission flushing machine?

A typical flushing machine uses hoses that connect into the transmission cooling lines. It drains the old fluid and holds it inside the machine while replenishing the transmission with new fluid. Unlike a simple pan drop, a flushing machine removes just about all the old fluid, including the fluid inside the torque converter.

Since the procedure uses new fluid to perform the flush, it requires several quarts of new fluid beyond the transmission’s final capacity. Those extra quarts are where most of the added cost lies.

(Find out how an automatic transmission works.)

The good ‘ol pan-drop

If you have reservations about a flush, go with a pan-drop instead. While it reduces the risk associated with flushing old, dirty fluid through the transmission, a pan-drop also has downsides.

  • Removes only about a third of the fluid
  • Can be a mess
  • Can be a pain on some vehicles

I can tell you from experience that a pan-drop can be a bigger job than you think. You may have to remove plastic splash guards or metal skid plates to access the transmission pan. In case you haven’t been under your vehicle in a while, plan on encountering rusted, stuck bolts if you drive in wet, snowy conditions. Don’t be surprised if you crack a splash guard in one or two places as you try to remove/reinstall it.

Tips for performing a pan-drop:

  • Have a large catch pan handy. Otherwise, once you loosen the pan bolts, fluid is going to ooze from the pan/transmission interface and end up all over the floor.
  • If you’re crafty, you can back out the pan bolts in one corner further than the surrounding bolts, effectively tilting the pan so the fluid drains from a single corner instead of overflowing the entire pan. This reduces mess quite a bit.
  • Wear safety glasses and gloves.
  • Don’t forget the new filter and pan gasket.
  • It’s a good idea to know the torque specs on the pan bolts and use a torque wrench to reinstall them. Otherwise you risk overtightening and ruining the gasket.

You might get lucky, though

Some vehicle manufacturers install a drain plug on the transmission, similar to a motor oil drain plug. This allows you to easily and cleanly drain some fluid from the transmission minus the hassle of removing the pan. Again, though, you only get a third to half the fluid out.

You can then drive the vehicle for a while, then drain the fluid and change it again. Do this 2-3 times and you’ll remove nearly all the old fluid and perform a sort of poor-man’s transmission fluid flush.

Bottom line: Visit a pro and have the transmission flushed for best results and least hassle (unless your vehicle manufacturer specifically warns against it in the owner’s manual). But, if you have reservations about dislodging debris due to old, dirty fluid, a series of pan drops works just as well.

FIND AMSOIL TRANSMISSION FLUID FOR MY VEHICLE

Transmissions, , , ,

Remember This When Trying to Find Which Transmission Fluid You Need

Written by Charleen

Remember This When Trying to Find Which Transmission Fluid You Need

John Baker|

Take a look at just a few of the dozens of automatic transmission fluid (ATF) specifications on the market:

  • ATF+4
  • Mercon V
  • Mercon LV
  • Dexron VI
  • ATF DW-1
  • ATF T-IV
  • SP-IV
  • Toyota ATF-WS
  • Honda DW (ZF
  • Diamond SP-IV

You’ve likely heard the term analysis paralysis.

That’s what many people feel when they scan the shelves at Advance Auto in search of transmission fluid. They just want a quart or two of ATF to top-off their vehicle, but instead they must decipher a series of hieroglyphics or face the specter of ruining their tranny by choosing the wrong fluid.

There’s a sure-fire way to avoid this hassle.

But first, check out this survey by the Petroleum Quality Institute of America (PQIA), which confirmed what many already know about buying ATF – the specifications listed on ATF labels can be confusing and misleading.

One reason is the sheer number of ATF specifications on the market. Interpreting the made-up words (“Mercon” and “Dexron” sound like diabetes medication or the latest U.S. Defense Department initiative, after all) leaves you shaking your head and vowing to service your transmission next spring.

It wasn’t always like this. At one time, Ford Mercon- and GM Dexron-type ATFs dominated the market and reduced your choices to a manageable few. Today, demand for those fluids has slipped below 50 percent and is declining as original equipment manufacturers (OEMs) continue to introduce their own, proprietary specs.

What is an ATF spec?

Simply put, it’s a set of performance standards. It’s not an actual fluid, meaning you don’t go to NAPA in search of Mercon or Dexron transmission fluid. You go in search of a fluid that meets the Mercon or Dexron specification. In an attempt to make it easy for you, many ATF manufacturers print those specs in giant letters on the label. Judging by the survey, though, it’s not working. This means the fluid was subjected to – and passed – a series of performance tests stipulated by the authors of the Mercon or Dexron specifications.

Today, it’s normal for most OEMs to author their own performance specifications rather than recommend using a fluid that meets a different OEM’s specifications, for example Mercon or Dexron. You can blame it on technological advancements that have made vehicles tougher on transmission fluid than cars of yesteryear. An automaker that introduces its latest 500-hp land rocket wants to be sure you’re using a transmission fluid capable of standing up to the intense heat and stress churning through all those gears.

It may also have something to do with money. Brand XYZ would rather you buy Brand XYZ transmission fluid than another company’s fluid, which helps explain why some OEM-branded fluids are so expensive.

That brings us back to analysis paralysis.

How can we cut through the confusion and make transmission fluid selection easy? And how do we do it while meeting the performance demands of most modern automatic transmissions?

One transmission fluid to rule them all

That’s a bit of hyperbole in honor of my favorite trilogy about hobbits and orcs, but it’s not far off.

We formulated AMSOIL Signature Series Synthetic Automatic Transmission Fluid and OE Synthetic Automatic Transmission Fluid to take the guesswork out of ATF selection. Both fluids are recommended for most of the common ATF specs on the market.

Mercon V? Check.

Dexron III? Check.

ATF+4? We cover that, too.

We take convenience a step further with our online Product Guide, which tells you which fluid your vehicle needs.

LOOK UP TRANSMISSION FLUID FO MY VEHICLE

If you tow, haul or engage in other types of severe service, use Signature Series Synthetic ATF. If you stick to the highway and mostly run to work and home, OE Synthetic ATF is your best bet.

So, when it comes to finding the right transmission fluid, forget about the hieroglyphics and just remember these six letters: AMSOIL.

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