Torque setting for transmission bolts

[toytime]

Oops I was changing transmission fluid and filter everything was going smooth until I started torqueing pan bolts the box that contained the filter and gasket gave a number of 12ft lbs. with all bolts snug I started to torque the 1st bolt and it snapped off guess I should have checked I out on the forum first, now I'm wondering if I need to drill it outer if I should try tightening the others and seeing if I can get away with one less bolt does anyone know the torque setting I should be using obviously it's not 12 or is it 12in lbs. any suggestions would be greatly appreciated. Ralph

[adamh]

no torque spec but here is a standard mrT chart for vans in the absence of listed values, just reference the bolt size.

[originalkwyjibo]

The factory service manual calls for 39 in lbs for the pan bolts and 13 ft lbs for the drain plug.

[toytime]

Thanks, 39 in. lbs. worked great, filled without removing snapped bolt no leaks, dodged a bullet on this one.

[yotajohn]

Figured I'd bump this thread rather than starting a new one.

I'm pretty certain my now 33 year old van has never had a transmission filter change, so I started by soaking all of the pan bolts with PB Blaster and Liquid Wrench 5x over 3 days. Wanting to get the van back on the road, I got impatient today and started removing the bolts. I managed to break 6 or 8 of them in the process.

Question 1: I have never worked on an automatic transmission before other than fluid changes. If I drill the broken bolts out and then thoroughly clean everything off with brake cleaner and compressed air, is that sufficient? Or do I need to be super worried about metal shavings getting somewhere I can't get them out (pan is currently off, filter is still on).

Question 2: I know the bolts are M6 but I'm having a hard time discerning the thread pitch. Anyone know if it is .75 or 1.0? I'm going to look into a higher grade replacement (and I'll make sure they don't stay on for 33 years lol).

Thanks!

[adamh]

Figured I'd bump this thread rather than starting a new one.

I'm pretty certain my now 33 year old van has never had a transmission filter change, so I started by soaking all of the pan bolts with PB Blaster and Liquid Wrench 5x over 3 days. Wanting to get the van back on the road, I got impatient today and started removing the bolts. I managed to break 6 or 8 of them in the process.

Question 1: I have never worked on an automatic transmission before other than fluid changes. If I drill the broken bolts out and then thoroughly clean everything off with brake cleaner and compressed air, is that sufficient? Or do I need to be super worried about metal shavings getting somewhere I can't get them out (pan is currently off, filter is still on).

Question 2: I know the bolts are M6 but I'm having a hard time discerning the thread pitch. Anyone know if it is .75 or 1.0? I'm going to look into a higher grade replacement (and I'll make sure they don't stay on for 33 years lol).

Thanks!

m6 x 1 is standard, 12.9 would be ok grades for steel. I think 10.9 is about T standard . they seem to last better underneath if partially smothered in sealant. Why Toyota used so many weak m6 hex set under their cars is a mystery. Bumper bar skins and such like also use that thread.

if drilling out the pan bolts upside down can be an issue... use a magnet to sweep up after, drill slowly, center punch bolts first. Avoid compressed air it may blow chips somewhere you can’t see

[yotajohn]

m6 x 1 is standard, 12.9 would be ok grades for steel. I think 10.9 is about T standard . they seem to last better underneath if partially smothered in sealant. Why Toyota used so many weak m6 hex set under their cars is a mystery. Bumper bar skins and such like also use that thread.

if drilling out the pan bolts upside down can be an issue... use a magnet to sweep up after, drill slowly, center punch bolts first. Avoid compressed air it may blow chips somewhere you can’t see

Thanks Adam, I did the best I could drilling upside down, which if there is a silver lining to that it's the fact that most of the shavings seem to have fallen on the ground. I found some zinc plated 10.9 bolts from belmetric.com, whom I've ordered from in the past. Waiting on some new fastener extractors from Lisle to show up and then hopefully I can put this whole saga behind me.

[adamh]

Thanks Adam, I did the best I could drilling upside down, which if there is a silver lining to that it's the fact that most of the shavings seem to have fallen on the ground. I found some zinc plated 10.9 bolts from belmetric.com, whom I've ordered from in the past. Waiting on some new fastener extractors from Lisle to show up and then hopefully I can put this whole saga behind me.

Good luck with the ez outs!, never had much luck with them in small bolts. drill 3.2mm then 5. Re run 2nd tap through carefully as the thread left breaks up, usually works good.