M998 6.2L Y-Pipe

[juanprado]

My M998 with 6.2L cracked the y pipe at both flanges meeting the exhaust manifold. I did add a fording exhaust several years ago with the correct under fender brace and all the hardware that it calls for. Muffler and and its extension pipe are all good and solid.

I do not have any vibrations that I can feel while driving it and I recently drove it on the highway an hour each way with no issues except it was noisier and I now know why.

How common is the failure of this item?

I have found one for sale with OE sticker with the correct nsn 2990-01-187-7168 and part number 12338351 and it states REV A. How do you know the latest revision for a part number or nsn?

Does anyone know what is the upgrade/difference on Rev A?

 

[mgFray]

I’ve got a related question. My M998 was upgraded to a 6.5L (by the army), which Y-pipe do I have? I suspect it’s the 6.2L, but I’m not sure.

 

[juanprado]

I believe they are the same. Double check me as I have not worked on a 6.5.
I saw a listing for a different y pipe for the 6.5 turbo.

 

[Mogman]

I also think the 6.2 and the 6.5NA have the same exhaust system, doubt any changes were needed when only adding 300CC and very few if any HP.
Something must have been out of alignment placing a load on the flanges, I have not ever heard this is a weak point.

 

[86humv]

6.2 /6.5na same basic Y pipe...there was a galvanized one and a stainless one...same shape...4 spd trucks had a shorter muffler with a Cat..
Turbo trucks have a single down pipe.