Thanks for quick reply. I figured it probably wasn't a known problem in 2001, but wasn't sure if it was part of the transmission assembly that would be replaced in the event of a failure.

 

The IMSB is part of the engine and separate from the tranny.

 

Charles is right on this issue not being well understood in 2001, but I have a follow on question for Blue Devil. Is the service record indicating a transmission replacement an actual receipt or a CarFax report? Back then, there wouldn't have been a CarFax code for an RMS or IMS replacement so they would code the transmission removed and replaced.

 

In 2001, it would have been under warranty (<3 yrs and 36,000 miles). If there was any suspicion of an IMSB problem, the dealer would have replaced the entire engine. The concept of replacing that bearing without cracking open the case was not an approach used by anyone at that time. Also, keep in mind that the bearing was not even available as a separate part, it came as an assembly with the entire Intermediate shaft.

 

I just had my IMS bearing and rear main seal replaced for the first time since owning my '99 996 C2. I tracked the car a couple times a year every year for the last 10 years with no issues. It just crossed the 100K mark on the odometer. So I decided to have the oil analyzed, which showed some small metal flakes in the filter. So to be cautious, I went with my mechanic's recommendation and had him install the LN Engineering single row bearing replacement. Everything is working great and the engine has never run more smoothly.

I should mention that my '99 996 had an engine replacement with its first owner in 2003. That included a double row bearing. When my mechanic opened up the IMS assembly, the bearings looked good. But there was some oil in the shaft and I had a very small slow leak from the RMS. That was enough for me.

The cost of the work was about $2600, which is about what I expected.

 

I own a 2002 996 Carrera 4 cab I bought second hand in 2005.
During some transmission service I had the IMS replaced at 100000 miles.
My shop owner retired , and the replaced IMS failed with no warning at 14ok.
It appears the LN IMS was never registered, so no warranty.
I decided on a dealer engine rebuild which cost $24k. I know this sounds stupid .
Now have 154k an the car, and still enjoying it.

It is quite possible I would never had an issue if I didn't preemptively replace the IMS.
Food for thought.

 

Exactly what happened to me, except in my case the replacement bearing was not an LN one and most likely installed incorrectly. I think it is very important when replacing the bearing to be sure the installer is following all LN guidelines to the letter. And I agree that with the original bearing, it would probably still have been purring along nicely.

After all this, I moved on to the Turbo because I was so fed up with the M96 issues.

 

dailly driver + many track days

 

996 Mk1, no failure at 112k miles but replaced then when replacing clutch

 

Yes -- LN bearing kit failed | '02 Carrera 4 Cabrio, tiptronic, no other significant mods

Bearing installed ~Feb.'13, so 10+ years and about 100k since installation. Started car late Sept this year and running rough, could hear a "tick tick tick" (RPM related) still didn't suspect the bearing given the LN kit had been installed.

Sent to shop though and confirmed, engine "muerto"!

Spoke to two different shop managers, including one who works closely with Flat-6 Innovations. Both said the IMS (even LN kit) should be considered a "maintenance" item, and replaced periodically. I had never heard this before and certainly hadn't thought about replacing it again.

In any case, pay attention to yours... ours probably could have been caught with more frequent oil changes, and perhaps a magnetic drain plug. Car wasn't being driven that much either, which may have contributed.

Regardless, loved having & driving the car for 10+ years. Sold to shop and probably moving up to 997.2 or 991.1.

 

It's documented the LN IMS replacement bearings are a wear item with a specified service life. The only solution that is permanent that I am aware of is the LN IMS Solution, an oil fed plain bearing system.

-Tom

 

Here is what they have published for the current versions of the product:

”The IMS Solution is designed to last the lifetime of the engine and does not have a service interval. The Dual Row IMS Retrofit™ and Single Row Pro IMS Retrofit™ both have a 6 yr or 75,000 mile service interval.”

I believe the older versions were 5 yr or 60k mile, but not sure when the change happened.

 

The original Single Row IMS Retrofit 106-08.2 had a 4 year or 50k mi service interval. We have not sold any of these kits since 2014 when it was superseded by the Single Row Pro 106-08.2.2 which uses a dual row bearing with a 6 year or 75k mi service interval.

https://imsretrofit.com/service-intervals/

 

I recently purchased a 1999 996 C4 with 82k miles. Apparently the motor was replaced by Porsche under warranty at about 34k miles. I have to assume a warranty engine replacement would only be for a catastrophic failure of some sort - like a IMSB detonating. Other than the engine serial number m96/0466Y20434, I have no info on what may have also been replaced with the engine replacement. I don’t know if the replacement motor is single row or double row. Car runs well with no ticks, no smoke, and no soot on tailpipes. I’ve been driving it as intended and enjoying every minute of it.

I want a driver, not a garage queen. I’m inclined to proactively do one of the IMS fixes, but the m96/04 seems to be a bit of an odd duck that there is not an abundance of info about. Any insight or input?

 

Thanks for clarifying / jogging my memory. Point is, these are a serviceable component and need to be serviced according to the lifespan of the part — it’s not one & done. With the exception being the IMSS (LN solution).