smg hydraulic pump factory

Renew your worn or burn"t out SMG pump with our remanufactured units! Our remanufactured pumps are disassembled, thoroughly cleaned and reassembled with all new components.

This part is listed by BMW as BMW part number 21532229715 (21-53-2-229-715) and is described as SMG Hydraulic Pump with Pressure Accumulator - E46 M3.

The SMG pump on the SMG (sequential manual gearbox) equipped E46 M3 is a very well known failure point. It"s really not a question of IF your SMG pump will suffer a failure, but when. Typically, the SMG pump lasts somewhere in the neighborhood of 100k miles, but they have been known to fail with much less miles.

If your E46 M3 has suffered the dreaded SMG pump failure, you need a new SMG pump. And BimmerWorld has the best price available to assist in getting your E46 M3 back on the road.

The accumulator is responsible to store the pressure of the SMG system for later access by the actuators. The piston type accumulator has two cells: one cell storing the hydraulic fluid and one cell containing a gas to create counterpressure. Both cells are separated by a moving piston. A broken accumulator causes the pump to prime permanently.

Pentosin CHF 11S is a synthetic high performance hydraulic fluid for life-time application in modern vehicle aggregates. Pentosin CHF 11S is especially designed for hydraulics in the automotive industry with the highest technical requirements such as in: power steering, level control, shock absorber, hydro-pneumatic suspension, stability and traction control, hydraulics for convertible tops, central lock systems, etc.

When our customer got into hisE46 M3recently and found that it wouldn’t start, a transmission problem was the last thing he suspected to be the culprit. There are many more common causes for a no start – like a dead battery, worn out starter, faulty brake pedal switch, etc.- and after checking the usual suspects and not finding the problem, he had the car towed over to our shop.How does the BMW SMG Transmission work?Just to clarify for those who aren’t familiar with BMW’sSMG transmission, the simplest way to explain it is that it’s neither a conventional “manual” nor “automatic” transmission, but more like a combination of the two. You still change gear much like you would in a conventional standard by using a “stick” of sorts (or by paddles mounted just behind the steering wheel), but there is no clutch pedal. Instead, the clutch is controlled electronically by a computer and actuated by hydraulics.Symptoms and Diagnosis: How to know when an SMG pump has failed and needs to be replaced.When the M3 arrived at the shop, we hooked it up to our computer diagnostics scan tool and found a DTC, or“diagnostic trouble code, “indicating a fault with the Park/Neutral solenoid, which is an integrated component on theSMG hydraulic pump assembly. The SMG pump (pictured below) is similar to an ABS pump in both appearance and function, but controls the hydraulic pressures in the transmission and not the brake system.

The car came with two transmission options — a 6-speed manual, and anSMG II gearbox. The latter turned out to be the cause of a serious issue that pulled many cars off the road. More specifically, the M3 E46 SMG pump issue is what caused all the ruckus, and today we’ll try to give you a brief rundown on what this issue means and how serious it is, or was.

Contrary to popular belief, the SMG II gearbox that BMW has installed in the E46 M3 isn’t an automatic gearbox, nor was it the first gearbox of its kind to be used ona BMW M3 car. Oh no, it was a fully manual setup with a clutch and everything, but no clutch pedal. Getrag and Sachs wanted to make something that is close to Getrag’s 6-speed manual in terms of build butwith a hint of Williams BMW F1 transmission mechanics.

Where most die-hard enthusiasts hit a divergence point with BMW as far as SMG transmission went, was the addition of the automatic mode. Despite this being a sequential box, this mode alone was enough for many to shun the SMG as inferior to the now legendary Getrag 6-speed manual.

Today, things are changing in favor of the SMG. However, some argue that such a change of heart was brought on by a severe lack of manual M3 E46s out there. That being said, there’s a reason why this is the case.

As it turns out, the manual gearbox elitists were correct to avoid the SMG II early on, but not because of their anti-anything-non-manual argument. No, they were right to avoid the sequential gearbox because it turned out to have a pretty serious Achilles’ heel.

If you own an M3 E46 with an SMG II gearbox, you’ve probably seen the dreaded cog wheel iconat least once during your time owning the car. On the odd chance that you’re among the lucky few who never had issues with their sequential transmissions, you either know someone who has had their car drop out of gear following the cog icon, or you’ve at least read one doom and gloom thread on your BMW enthusiasts forum of choice.

The sequential M gearbox is anything but simple. In essence, it’s ahydraulic-driven manual transmissionthat is packed full of extras and goodies such as an early version of a hill-assist, different shift programs, and more. To make all that happen, BMW had to use a fairly complex network of hydraulics, which were driven by the SMG hydraulic pump.

That pump is where most issues with this transmission start and end, at least the serious ones. Decades have passed since we first heard the horror stories of SMG II-equipped cars dropping out of gear while their owners were doing 70 MPH on the freeway, leaving them dead in the water with no real ability to limp the car to the nearest off-ramp.

Yet, despite so much time passing by, there are still conflicting reports of why these pumps, or more specifically the electric motors inside them, fail the way they do. The general consensus is that Bavarian engineers simply chose a bad spot to mount the pump, i.e. way too close to the engine block.

The heat from the engine would cut the lifetime of the electric motor short, causing it to grow weaker over time until it reaches a point where it can no longer deliver the necessary pressure to run the pump. Once the drop in pressure occurs, it usually renders the car unable to stay in gear. Most SMG pump issues of this nature manifest themselves well before the car has 100,000 miles on the odometer.

Another potential culprit that many feel affects the SMG II is the overly optimistic transmission fluid flush cycle. Many owners swear by doing a transmission fluid flush every 20,000 miles, using quality MTF-LT-2 fluids, thus keeping the fluid in a pretty good condition at all times.

So many SMG pumps were replaced within the first 10 years of the M3 E46 production that many owners contemplated a class action lawsuit against the German manufacturer.

The answer is that it depends. Back in the day, it was pretty much an unwritten rule to have a few grand stashed away somewhere just in case the hydraulic SMG pump decides to head for Valhalla.

BMW was pretty adamant about replacing the entire unit instead of just the electric motor inside the pump. Since there weren’t really any other options available, people did what they had to do, begrudgingly.

Now that we as a community have some hands-on experience with these pumps, their motors, and the SMG II as a whole, people have recognized that once you replace the motor, you should also replace the relay which tells the motor when to come online and when to turn off.

Faulty relays are right behind the SMG pump issue in terms of things that will leave you stranded on the side of the road. So much so that people often replace these relays as means of preemptive maintenance.

This is where things turn a little sour for most people. While the electric motor failure accounts for the majority of SMG pump issues, there are still the other 15-20% of cases where the motor could be fine. Well, you’re probably thinking, we can simply diagnose those other things and replace them as need be, right?

Unfortunately, that’s not the case. A failed pump results in a drop in oil pressure within the system, which triggers the SMG-specific codes. The trouble is that a failed solenoid or a relay will do the same. Many people have found themselves replacing the electric motor only to find out that it’s the solenoid that has triggered the code in the first place.

Like with most things in life, the answer to this question isn’t so simple. On one hand, the issues related to the SMG II gearboxes have made them somewhat notorious in the community. On the other hand, a byproduct of such a bad rap is a decent availability of fairly healthy cars that haven’t been ragged on all that much. You could find yourself an M3 with a decent amount of miles and a relatively fresh engine.

Burkhart Engineering, based in southern Germany, is a BMW specialist renowned worldwide for its expertise with the E46 M3 SMG2 transmission system. Through countless repairs and a refreshing approach to the problems the SMG system can present, Burkhart has since developed a range of rebuild kits and upgrades to make SMG ownership a worry-free experience.

The Burkhart Engineering SMG Hydraulic Pump Repair Kit can not only repair your pump, but also improves it to be ready for high temperature track use, traffic jams and hot summer weather.

In most cases this is caused by a worn electric motor, which drives the hydraulic pump in the SMG unit. Further the gap leakage in the hydraulic system increase massively during high temperatures. If additionally many hydraulic consumers are working (clutch slave cylinder and gearbox actuator), the hydraulic unit no longer produces enough pressure – for this issue Burkhart Engineering High Performance Hydraulic Fluid offers a huge improvement.  The pump runs on pressure up to 25% fasterthan using the conventional Pentosin CHF 11s.

The old motor can be replaced by the new one as a plug and play swap. The replacement motor is equipped with the required pins and seals and can be directly installed with the original wiring loom. These are brand new spare parts in OEM quality –  the alternative to save you from buying a complete new SMG hydraulic unit.

This Repair Kit only works if the rest of the hydraulic unit is functional. The accumulator for example needs a defined preload pressure. Should this not be the case, the accumulator has to be replaced, too. In Burkhart Engineering’s SMG-Wiki you can find instructions about how to check the preload pressure in the accumulator.