Transmission Crossmember problem! HELP!

[DaPCWiz]

Okay, so I bought my 240 with knowledge that the auto tranny that was in there was recently swapped because the original had blown.

About a month after I bought the car, we did an auto to manual swap. While doing this swap, it was noticed that 3 of the bolts were the normal 17 mm bolts, and one was a 14 mm bolt.

When we put the 14 mm bolt back it would reach a point where it was reasonably tight, and then just spin. Mounted everything up with it as tight as possible, and it worked.

Fast forward to like today (1.5 years later). I put in nismo motor mounts and tranny mount (brand new). I drive around for a couple days and I notice the following.

(a) there is a loud quick rattle from the bottom of the car when I start it.

(b) there is a loud rattle from the floor (can feel the vibration too) sometimes when coming off the clutch slowly in 1st gear.

I checked under the car, and the 14mm bolt was working itself out. So basically the 14 mm isn't holding, 17 mm doesn't fit in the hole. I need to figure out how to fix the threading on the chassis so that I can put a 17 mm back in there. Need this fixed asap as I daily drive the car.

what do I do :eek3:

[96Turbo]

drill that shit out and rethread a size bigger......not sure you have any other options

[kcndizzle]

Get a tap and chase the threads, or if the threads are that gone, redrill bigger and heli-coil. Or just run three bolts? But that's not a good option...

[DaPCWiz]

drill that shit out and rethread a size bigger......not sure you have any other options

how do I do that / could I get that done somewhere? I don't have a clue as to what that involves...

[kcndizzle]

how do I do that / could I get that done somewhere? I don't have a clue as to what that involves...

You get the proper size drill bit, then the proper sized tap. You don't really need to go anywhere, you just need a drill and some patience. Or order a heli-coil kit and make it really strong.

[96Turbo]

get a metal drill bit that almost fits into the hole but not quite. Drill it out, use the corresponding size tap (device that cuts threads into metal), and go buy some bolts at the hardware store with that same thread and a similar length. Voila!!

[pbcstylez]

i second the helicoil, but for ease and practicality jsut rethread the next size up

[downshift_sideways]

I 3rd that. Go to your local auto parts/hardware store.
Show them the thread pitch of the bolt that used to go into the crossmember.
Get a "tap" that is the next size up. Retap the hole with the bigger thread. Insert a new bolt that screws in good. (same size)

[projectRDM]

FYI, be extremely careful doing this. The nut on the chassis is just tacked welded in from above and can sheer out easily if the tap binds too much. Then you'll just have a big gaping hole and nothing to fill it with. Start drilling slowly, with one size bit up, using plenty of oil.

[S14DB]

I swear almost every 240 I see is missing that bolt.

[DaPCWiz]

ended up retapping the hole, worked out well - took like 15 minutes. Thanks for the advice guys :bigok:

also found out that hte noise wasn't the crossmember, but my exhaust tapping my drive shaft... yay more problems. gotta find a solution to that now.

[Dream240]

also found out that hte noise wasn't the crossmember, but my exhaust tapping my drive shaft... yay more problems. gotta find a solution to that now.

Heh, yeah the nismo tranny mount lifts the tranny tail up about 1-1.5 inches. You'll also have problems if you ever decide to run an aftermarket header. It'll prolly hit the firewall just behind the steering knuckle. A hammer fixes that one though. :)

Glad you fixed the bolt problem. And yeah I would never drive around with only 3 bolts holding my tranny tail up. The torque stress alone could create some major problems.

[DaPCWiz]

Heh, yeah the nismo tranny mount lifts the tranny tail up about 1-1.5 inches. You'll also have problems if you ever decide to run an aftermarket header. It'll prolly hit the firewall just behind the steering knuckle. A hammer fixes that one though. :)

Glad you fixed the bolt problem. And yeah I would never drive around with only 3 bolts holding my tranny tail up. The torque stress alone could create some major problems.

I do run an aftermarket header. Hot Shot. Clears just fine :)

[Dream240]

I do run an aftermarket header. Hot Shot. Clears just fine :)

Well there you go. Too bad Hotshot doesn't make them anymore. From all I've heard, the cheapy brands have clearance issues with Nismo mounts.

I had hotshot too back in the day and it actually hit my steering knuckle. Had to shave the knuckle down.

[DaPCWiz]

Well there you go. Too bad Hotshot doesn't make them anymore. From all I've heard, the cheapy brands have clearance issues with Nismo mounts.

I had hotshot too back in the day and it actually hit my steering knuckle. Had to shave the knuckle down.

I've heard that problem with S13s... not with 14's tho... mine clear fine. ::shrug::

[ManoNegra]

Happens a lot with swaybar bolts aswell. Helicoils.