I recently had my auto trans serviced. The tech removed the cross member to remove the pan on the trans. After the service, when the cross member was re-installed one of the bolts didn't tighten up very good because the threads in the nut "welded" to the unibody was weak.

Has anyone had any experience fixing this? I would like to fix it with a helicoil because I want to use the same factory bolts.

A gent who is a pro at repairing cylinder head and exhaust threads told me that he'd ruin his tools if he tried to install a helicoil in this place on my unibody frame.

I think it would be the exact type of repair for a helicoil.

Does anyone have any comments or advice? Thanks.

 

if the wedled nut has not actually broken from the sheetmetal, the common fix is to drill the hole larger and re-tap it to a larger size, i think 7/16-fine thread is the next common size? check it out.

i dont think the insert is thick enough to use a helicoil.

 

Right: it's not really quite a "nut"; it's some chinesium junk loosely held in an approximately correct area by a little sheet-metal cage.

I wouldn't mess with it if it's screwed up. Tapping it is only a temporary solution at best, even if it ever works at all. Sometimes the reason they screw up isn't even because they're "stripped"; rather, it's because the chinesium "nut" split, like a lockwasher. You can tap that every day from now til Doomsday, and twice on Sundays for good measure besides, and still NEVER get a bolt to hold in that.

Correct way to fix it is to take a hole saw to the floor pan right above it; nuke the lame factory one-time-use garbage; and put an actual NUT there instead. Made of steel and everything.

 

Thanks for your reply, 86TA. I thought about going 7/16 but I wanted, if possible, to repair these threads such that I could use the original bolts and have all four bolts on the cross member be the same. I may just have to go "oversize" to make the cross member solid. I appreciate your response to my post. Thanks.

 

Sofakingdom: I didn't think of replacing this "nut" and I didn't think that it might be split. If I was to go through the floor and installed a real nut -> that would be the 100% job. Thanks for pointing all of this out to me. Gary.