History/Background of This Engine

The Magnum 3.9 V6 was introduced in 1992. In 1997, a TSB was issued to fix excessive timing chain noise. The fix was to remove the cam thrust plate and chain oil tab and install the new thrust plate / chain oil tab / chain tensioner combo.

A popular option is to install a double roller timing chain instead. With a double roller, you leave the original thrust plate and chain oil tab in place and do not install the chain tensioner.

My Situation

I have a 1998 model year truck and I don't know what "year" my 3.9 engine is.

It has excessive timing chain noise and I'm pretty sure it was not replaced at the scheduled service interval so I plan to replace the timing chain. I already ordered a double roller before thinking about this.

Due to there being excessive noise, I assume that my engine was built before that TSB and does not include the tensioner.


If my truck does have the one piece thrust plate / chain oil tab / chain tensioner combo, what do I need to do to install a double roller?

I've looked at all my local auto parts stores and am now kind of crunched on time to order online. I've even asked for the part from a 1996 (pre-TSB) thrust plate, but no luck.

Can I take my dremel and trim off the tensioner parts of the combo piece? If so, how do I clean up the piece so there are no microscopic metal shavings left?

1 Answer 1


Look at the manufacture date of your truck. If it is after June 2007, you can pretty much be assured you shouldn't have to worry about the TSB since it is dated 27 June 2007. This wouldn't be foolproof, but one would have to assume they wouldn't put the old problem into a new truck after that date, considering they knew about the issue prior to that date.

As far as the DRTC, you'll need to fit and clearance as you go. This is just going to be one of those things. You may want to do further research with online forums for a "good solution" to this.

Cleaning metal debris off of the part if you do decide to clearance should not be too difficult. After you have finished grinding on it, put a pair of leather gloves on and check the cut areas for spurs which may cut you. Once you are sure there aren't any sharp edges, completely wash it in a parts washer. If a parts washer is not available, put it in a bucket and wash the part with soap and water. After that, completely soak the part in WD-40 (WD-40 was originally designed as a cleaner for the skin of aircraft, so works great for this cleaning application as well). Then take a clean paper towel and wipe the part down. Look over the paper towel to see if there is are any debris on it. Your looking for dark grey discoloration (not discoloration from the WD-40). If you see it, wipe it down again until you the paper towel comes back clean. (NOTE: If you are wondering about putting a metal part in soapy water, don't be. Part of the reason for using WD-40 is to disperse the water as well ... pulling double duty!)

  • Awesome! Thank you @Paulster2 for alleviating my fears. I know what to do now and will accept this answer Monday-ish, after I actually get in there and tell you if the June 1997 manufacture date thing works out. Jul 23, 2015 at 2:53

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