Step by step C6 front seal replacement
#1
06-17-2007, 03:24 AM
Join Date: Oct 2006
Location: New Orleans--High Ground
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Step by step C6 front seal replacement
Pretty sure I need to replace the front seal for the C6 on my 1978 f150 4x4.
The last owner had it sitting around for over a year and it began leaking not long after I bought it.
It just slowly leaks out from where the inspection plate would go. It will leak when just sitting in the driveway. I tried the Lucas tranny gunk and it still leaks. It shifts great, just leaks slowly.
I am looking for a step by step guide to replacing the seal, Oring, maybe lock nuts, and whatever else I need to do.
I am a part time mechanic and have access to a shop, lift, tools and can probably get the tranny stand somewhere. Ive done all the other work to my truck, just never new seals.
The last owner had it sitting around for over a year and it began leaking not long after I bought it.
It just slowly leaks out from where the inspection plate would go. It will leak when just sitting in the driveway. I tried the Lucas tranny gunk and it still leaks. It shifts great, just leaks slowly.
I am looking for a step by step guide to replacing the seal, Oring, maybe lock nuts, and whatever else I need to do.
I am a part time mechanic and have access to a shop, lift, tools and can probably get the tranny stand somewhere. Ive done all the other work to my truck, just never new seals.
#2
06-17-2007, 03:28 AM
#3
06-17-2007, 06:05 AM
The easiest and safest method.
Somehow stand the transmission on the output shaft so the pump is facing up.
Remove the pump retaining bolts.
Tap 2 oppossing holes in the pump body with a 3/8 NC thread.
Tighten the band adjusting screw.
Install a slide hammer into the tapped holes.
As the slide hammer is being used push down and keep pressure on the input shaft.
This will keep stuff from falling apart inside.
Once the pump has been removed take it apart.
Pay attention to how the gears are installed before you remove them.
There is a gasket and square cut "O" ring to replace along with the seal.
Use a screw driver and tap the seal out.
Apply a bit of sealant to the outside of the seal only.
Reassemble the pump.
Clean any caked on gasket material from the case.
Install 2 5/16" guide studs into the case.
Place the gasket over the studs.
Install the "O" ring.
Apply some atf or light grease to the "O" ring, no sealant.
Loosen the band adjuster screw.
Carefully install the pump.
Torque the bolts to 16-30 foot pounds.
Lay the transmission down and adjust the band.
Torque the adjuster screw to 10 foot pounds and back it off 1 to 1 1/2 turns.
Somehow stand the transmission on the output shaft so the pump is facing up.
Remove the pump retaining bolts.
Tap 2 oppossing holes in the pump body with a 3/8 NC thread.
Tighten the band adjusting screw.
Install a slide hammer into the tapped holes.
As the slide hammer is being used push down and keep pressure on the input shaft.
This will keep stuff from falling apart inside.
Once the pump has been removed take it apart.
Pay attention to how the gears are installed before you remove them.
There is a gasket and square cut "O" ring to replace along with the seal.
Use a screw driver and tap the seal out.
Apply a bit of sealant to the outside of the seal only.
Reassemble the pump.
Clean any caked on gasket material from the case.
Install 2 5/16" guide studs into the case.
Place the gasket over the studs.
Install the "O" ring.
Apply some atf or light grease to the "O" ring, no sealant.
Loosen the band adjuster screw.
Carefully install the pump.
Torque the bolts to 16-30 foot pounds.
Lay the transmission down and adjust the band.
Torque the adjuster screw to 10 foot pounds and back it off 1 to 1 1/2 turns.
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#7
10-14-2017, 05:58 PM
Lead Driver
My '77 did the same some .... 105K miles.
Updated to say while the inspection plate was wet outside, I removed it here in 2021 and the plate was clean and dry inside surface and a swipe of a clean finger into the bell mousing area under the TC revealed it seems clean and dry, so my leak onto the exhaust cross over is some oil from the rear of the oil pan, the bolts were not tight due to compression of the gasket I guess ... and it leaked all around actually. The trans pan gasket might leak some too.
Updated to say while the inspection plate was wet outside, I removed it here in 2021 and the plate was clean and dry inside surface and a swipe of a clean finger into the bell mousing area under the TC revealed it seems clean and dry, so my leak onto the exhaust cross over is some oil from the rear of the oil pan, the bolts were not tight due to compression of the gasket I guess ... and it leaked all around actually. The trans pan gasket might leak some too.
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