Rear diff cover bolts

[cthudak]

Hi guys,
I have a 2006 trailblazer LWB. I changed the rear diff fliud a few months ago, and now the rear diff cover has developed a very slow leak. I fear I may have one or 2 damaged heli-coil inserts for the cover bolts.( rigid cover gasket was difficult to align) I know the bolts have 11mm heads, but I need help knowing what size / part # heli-coil inserts I may need if it come down to having to replace the inserts. Has anybody researched this? any help is much appreciated.

Thanks,

Tom

 

[The_Roadie]

When delivered from the factory, those holes were just threaded into the aluminum casting. No helicoils. So somebody messed them up in the past, and stuck you with a modification nobody here can guess what thread is in there. I think they were 6mm or maybe 8mm threads, but I forget the pitch. Recommend just buying a few different sizes and trying them. Helicoils, being steel, are less likely to be damaged than the OEM aluminum. If the bolts fit and torque down nicely, I'd just pull the cover and add a thin layer of gasket RTV to each side as you reassemble it.

 

[cthudak]

Roadie,
Thanks for the great info. You've saved me more than a few times over the years.

Tom