The Trouble with Damaged Flywheels Begins

For many years Bosch remanufactured part number SR82X has been a very popular and (the only) remanufactured starter SKU available for Volkswagen Jettas and Golfs equipped with a 1.8L engine.  Traditionally this SKU has been just like any other Bosch remanufactured starter in that it had some of the industry's lowest warranty return rates related to it.  That is until recently when complaints have been received of damaged flywheels after installing an SR82X.

Initial Investigation

After much contact with puzzled installers and vehicle owners, Bosch reviewed not only the paper work involved with warranty claims on these units but also the "alleged" failed units themselves.  Upon inspection all the starters which were returned for warranty performed to Bosch specification on a test bench, further inspection revealed that some of the starters did show signs of damage to the teeth on the pinion gear.  In some cases the installers had installed multiple starters and flywheels on the same car resulting in the same outcome each time...a damaged/noisy flywheel and starter engagement!

A Fly in the Ointment!

One of the SR82Xs which was returned for warranty held an unusual surprise:  both the flywheels which had been damaged on the car were returned with the unit.  They were not the same!  At first it was assumed that the person returning the unit for warranty had accidentally put a wrong flywheel in the box.  In the process of checking everything out, the customer was contacted about the difference in the flywheels.  They informed Bosch that indeed both of the flywheels had come off of the same car, but one of them was the original from the car and the other was a replacement which they purchased from VW.  When they purchased the replacement flywheel, they not only got a flywheel but a set of shims and an involved set of directions detailing how and where to make measurements before installing the shims to determine how many and which shims to install.  This customer also informed us that the flywheel was provided by VW at a cost of over $300.00, and that to install it ... Yes, you guessed it-the transaxle has to be removed so there are several hours and dollars of labor involved also.

Puzzling Pinions

At this point the question still remained, how come this milling of flywheels and pinion gears only occurs some of the time when all of the SR82Xs are built the same?  We directed our attention back to the only thing that was different in this equation:  the ring gears.  The original ring gear, which has the appearance of a "dished" tire rim, was noticeably narrower across the edges of the teeth than the replacement.  The replacement also looked very much different than the original in that it was not a solid, one-piece ring gear; it had more of the appearance of a "mag" wheel or a custom steering wheel.  With these quite apparent differences in the two ring gears there must have been a reason that Volkswagen had superseded the original with the newer modified version.

Back to the Source

After checking several sources of O.E. technical service bulletins, it was discovered that in 1990 VW issued a tech service bulletin (#91-03) stating that if a Jetta built before VIN 1G LW 746 848 or October of 1990 was diagnosed with a noisy flywheel, it should be serviced with a "revised starter and flywheel" to cure the condition.  It also stated that all Jettas built after that time were built with the revised components.

What's So Different?

The on-going investigation already showed that the revised ring gear was visually different in appearance and had wider teeth than the original.  But what about the starter?  All indications were that the starters looked the same.

Back to the Source, Part II

Further checking with sources at VW revealed that with the need to correct the noisy starter engagement problems on early Jettas,  VW needed to increase the amount of engagement between the teeth on the pinion gear and the ring gear.  To do this they had revised the dimensions of the ring gear and some of the features of the starter.  Further checking revealed the biggest problem was the fact that the part number of the original starter and the replacement starter were exactly the same, and there was very little physical difference between the two!

Identification of Early vs. Late Style SR82Xs

In order to make the required changes to the starter for correction of the noisy engagement problems, it was necessary for the original starter manufacturer to make a new drive end housing for the starter. In casting this housing, a couple of small identifying markings are all that one can actually see to determine a late style starter from the early style.

New SKU

In order to provide proper coverage for the differences in the vehicles we now know are out there, Bosch had to add another SKU to the SR82X range of applications.  That new part number (SR0782X) is in the 1998 Bosch Reman. catalog (#221130).

Still Complicated

If the world were simple, we could say that the SR82X fits all Jettas built prior to VIN 1G LW 746 848 or October of 1990, and that the SR0782X fits any Jetta built after that VIN date.  And to a great extent that is true.  But...The world isn't that simple.  If you need to provide a starter for any of the early Jettas built prior to October of 1990, you can't just order a replacement part based upon the application or the part number on the starter.  Remember, the replacement starter and the original have the same exact OEM numbers stamped into the housings.  This is due to the fact that these cars are getting older now, and without actually looking at the starter or the flywheel, you have no way to determine if the original starter and flywheel were replaced with the later versions as per the Volkswagen tech service bulletin for noisy starters.

If, for example, the late style flywheel has already been installed on the vehicle and you sell/install the early style (SR82X) for that vehicle, you will actually make the problem worse as the shimming of the replacement flywheel and the different dimensions of the later style flywheel will actually make the gear engagement problems worse!  And you guessed it...the late style (SR0782X) will not work properly with the early style flywheel either.  

Proper Identification

So - all of this explanation boils down to the following:

1. For Jettas built prior to VIN 1G LW 746 848 or October of 1990, the only sure fire way to provide the correct starter for the vehicle is to look at the starter drive end housing of the starter removed from the vehicle and, as per the figures provided, identify whether the unit is an SR82X or an SR0782X.  Only after properly identifying the original unit should the replacement be ordered/installed.
2. For Jettas built after October of 1990 the SR0782X is the correct replacement.

A more condensed explanation of this situation is provided in a Bosch application notice (B-105) which is packaged with each SR82X as well as SR0782X.  In the 1998 Bosch Reman. catalog all SR82X and SR0782X applications are footnoted alerting customers to this situation.  In addition, application notice B-105 appears in full on page 270 of that same catalog.  

It may seem like a lot of extra work to properly identify the correct replacement unit for the early Jettas, but several hours of your labor time and a $300.00+ flywheel are probably worth the inconvenience.