Aisin Transmission Pan Torque Specs

[RollTide1126]

Does anyone know the torque specs for the 10mm bolts on the transmission fluid pan. I’m going to do the service and don’t want to over tighten them and risk damaging the gasket. I searched the forums but didn’t find this specific info.

 

[gsbrockman]

Use common sense and nothing more than a 1/4” drive ratchet......only after using a 1/4” drive nut driver. It’s not holding an alternator bracket on.....just pressing two pieces together between a reusable gasket for leak prevention.

 

[endoscott]

My mechanic friend told me once "tighten your sparkplug as much as your girlfriend could do. " I guess these days "as much as the guy at Starbucks with the man bun". I do like having torque specs though. Love my little Snapon quarter inch drive torque wrench. Really good for tractor/mower work.

 

[Ozymandias]

It's M6 bolts with a 10mm head.

 

[Joseph Donnelly]

There are no grade markings on the bolt heads so I assume they aren't very high grade. The ones in my Aisin pan are just a bit more than nut driver snug. One owner reported that the dealership told him they broke off 6 of them which could be from the tech using an air ratchet, who knows. I am replacing mine with grade 12.9 allen head to remove that weak point, even though I won't tighten them more than stock. If you haven't notched your crossmember, you will need a ball end allen wrench, or keep hex head bolts in the rear positions for use with a wobbly extension and very short socket.

 

[Cummins12V98]

"wobbly extension and very short socket"

Works GREAT

 

[Ozymandias]

There are no grade markings on the bolt heads so I assume they aren't very high grade. The ones in my Aisin pan are just a bit more than nut driver snug. One owner reported that the dealership told him they broke off 6 of them which could be from the tech using an air ratchet, who knows. I am replacing mine with grade 12.9 allen head to remove that weak point, even though I won't tighten them more than stock. If you haven't notched your crossmember, you will need a ball end allen wrench, or keep hex head bolts in the rear positions for use with a wobbly extension and very short socket.

8.8 grade is plenty strong enough to rip the threads out of the aluminum case.
12.9 are rare to find and waaaaaaay overkill for that application.

 

[bcbender]

M6 bolt threads are generally 8-12 Nm, not very much and as Ozy said easy to strip the thread if not break the bolt off first, not sure what FCA SPEC is.

 

[DBrooks]

It doesn't take much, I looked this up last time I did mine and I have it in my notes as 62 inch/lbs

 

[Joseph Donnelly]

Grade 8.8 are 110k psi strength, and 12.9 are 170k. McMaster-Carr offers both with the high grade allen head cap screws costing about $4 more per hundred than the lower grade hex heads. What can be hard to find is the proper length cap screws. Stock are 16mm long below the captive washer. Washers are commonly 1.4 mm thick, and the threads in most of the transmission case holes are open so longer bolts work fine. At the rear, holes are closed but 18mm long with a washer work and give more threads in the aluminum (16.6 mm effective length) than the shorter 16mm length would do (16-1.4=14.6 mm effective length).

Now, if the person tightening the cap screws makes a mistake and overtightens them, what happens? I would much rather strip the threads of the aluminum case than break off a bolt. I would rather not have to perfectly center the left hand drill bit to drill out a hardened broken bolt, or hopefully turn out the broken bolt. I would rather install a heli-coil in the stripped hole. Mostly, I would rather not tighten the bolt enough to strip the case or distort the sealing surface of the pan.

As I stated above, I wanted to remove bolt strength from the list of possible issues and problems.

 

[BigPapa]

Ding, ding, ding! DBrooks is the winner.

 

[Ozymandias]

Here is the max. Torque for the M6 bolts.

M6
Grade 8.8 7,69 Nm
Grade 12.9 17,29 Nm

These values are for max. strength of the bolt, they do not rip of at that certain point.

I just don't get the point here, I never ripped an M6 bolt during the last 35 years with just feeling the tightness by hand. It must be a gorilla tightening these pan bolts to strip them.
I wouldn't even consider a torque wrench for these bolts, simply not, not needed.

 

[BigPapa]

Does anyone know the torque specs for the 10mm bolts on the transmission fluid pan.

This is a common mistake that I've never understood and it can get you in trouble. As Ozy mentioned, they are 6mm bolts, not 10mm. This doesn't happen with SAE bolts. Nobody calls a 1/4-20 bolt a 7/16" bolt or a 3/8-16 a 9/16" bolt. Standard torque for an M6 is less than 9ft/lb while an M10 is north of 40ft/lb.

 

[Cummins12V98]

"Grasp" the handle with your thumb on the head of a 1/4" ratchet and give firm pressure. Good E nuff.

 

[Ozymandias]

Grasper the handle with your thumb on the head of a 1/4" ratchet and give firm pressure. Good E nuff.

Exactly so!

 

[crazy jerry]

problem with giving it firm pressure is theres no industry standard of what firm pressure meens. torq wrench can get it to 5ftlb in nearly the same amount of time. even 2ftlb variance on those bolts can meen youll be under there doing the job over. trust me ive been there

 

[User113]

You need to re-calibrate your thumb.