Auto transmission pan bolt sequence?
12-08-2013, 01:27 PM
#1
Burning Brakes
Thread Starter
Auto transmission pan bolt sequence?
I got a new gasket for my '79 transmission automatic oil pan but when I took it off I didn't realize there are three different types of bolts that held it on. 8 are the same and the other 5 are all somewhat different. How can I find out the exact placement for the bolts in the 13 holes without spending hours in the cold and possibly ruining the gasket I had to wait 3 days to get?
thanks
thanks
12-08-2013, 10:31 PM
#2
Team Owner
The 'sequence' of tightening auto tranny pan bolts is not nearly as important as the 'method' of setting bolt torque. These pans are sheet metal and the gaskets usually get compressed quite a bit.
The key to a good pan seal is to use a good quality composition (cork and rubber combination) gasket. If you want to guarantee a good seal, put a wipe of Permatex #2 gasket sealer on each side of the gasket [put it on one side; install the gasket on the pan; put sealer on the other side; install pan with two bolts finger tightened at diagonal corners]; install all bolts finger tight.
To torque them (spec should be about 7-8 ft-lbs / 84-96 in-lbs), start anywhere and work around the pan in sequence tightening to 30 in-lbs on first round, then to 60 in-lbs. Let set overnight and allow the sealer to set up fully. Then do one more round of torquing to 90 in-lbs.
P.S. Trying to set torque this way with a "Foot-Pound" torque wrench is questionable, at best. Torque accuracy in the first 10% of the scale is very poor. If you don't have an Inch-Pound torque wrench, you'd probably be better off using a 6" long end-wrench and applying 5 pounds of 'pull' on the first round; 10 pound pull on the second round; and 15 pounds of pull on the third. Whatever you do, don't overtorque those tranny pan bolts. If you do, you will 'dimple' the pan at the bolt areas and cause it to leak and/or you could strip out some threads and force you to do some Heli-Coil repairs. Not fun....
The key to a good pan seal is to use a good quality composition (cork and rubber combination) gasket. If you want to guarantee a good seal, put a wipe of Permatex #2 gasket sealer on each side of the gasket [put it on one side; install the gasket on the pan; put sealer on the other side; install pan with two bolts finger tightened at diagonal corners]; install all bolts finger tight.
To torque them (spec should be about 7-8 ft-lbs / 84-96 in-lbs), start anywhere and work around the pan in sequence tightening to 30 in-lbs on first round, then to 60 in-lbs. Let set overnight and allow the sealer to set up fully. Then do one more round of torquing to 90 in-lbs.
P.S. Trying to set torque this way with a "Foot-Pound" torque wrench is questionable, at best. Torque accuracy in the first 10% of the scale is very poor. If you don't have an Inch-Pound torque wrench, you'd probably be better off using a 6" long end-wrench and applying 5 pounds of 'pull' on the first round; 10 pound pull on the second round; and 15 pounds of pull on the third. Whatever you do, don't overtorque those tranny pan bolts. If you do, you will 'dimple' the pan at the bolt areas and cause it to leak and/or you could strip out some threads and force you to do some Heli-Coil repairs. Not fun....
12-08-2013, 11:48 PM
#3
I got a new gasket for my '79 transmission automatic oil pan but when I took it off I didn't realize there are three different types of bolts that held it on. 8 are the same and the other 5 are all somewhat different. How can I find out the exact placement for the bolts in the 13 holes without spending hours in the cold and possibly ruining the gasket I had to wait 3 days to get?
thanks
thanks