‘86 C10 700R4 pan leak with new gasket

[BlazerBill]

My ‘86 C10 700R4 trans pan with a cork gasket was leaking so I dropped the pan and installed a new Moroso rubber with steel core gasket and was very careful with torquing the bolts and in a cross pattern. The pan continued to leak and I have loosened and retorqued the bolts with varying amounts of torque multiple times now and it still leaks around almost the entire perimeter of the gasket but mostly around the front 3 sides. After about 1-2 weeks of sitting it will develop around a 5” diameter puddle on the concrete floor. When I had the stock trans pan off I didn’t notice any damage or distortion of the flange. Are these $43 Moroso gaskets PN 93104 that I installed not any good or should I buy a new pan? If so, which pan (with drain plug) and gasket is best? Any recommendations would be appreciated, thanks!

 

[PrairieDrifter]

Check the dipstick tube and tv cable seals. Trans fluid is bad about pushing out after sitting and temp fluctuations. Don't store a full trans with no plugs. Ask me how I know lol. Felpro is my go to.

 

[Ricko1966]

It was leaking before and leaking after,and retorqued and still leaking. My guess is front pump/torque converter is leaking running down and following the pan rails down both sides.

 

[NickTransmissions]

My ‘86 C10 700R4 trans pan with a cork gasket was leaking so I dropped the pan and installed a new Moroso rubber with steel core gasket and was very careful with torquing the bolts and in a cross pattern. The pan continued to leak and I have loosened and retorqued the bolts with varying amounts of torque multiple times now and it still leaks around almost the entire perimeter of the gasket but mostly around the front 3 sides. After about 1-2 weeks of sitting it will develop around a 5” diameter puddle on the concrete floor. When I had the stock trans pan off I didn’t notice any damage or distortion of the flange. Are these $43 Moroso gaskets PN 93104 that I installed not any good or should I buy a new pan? If so, which pan (with drain plug) and gasket is best? Any recommendations would be appreciated, thanks!

To @Ricko1966 's point, verify that it is the pan that's leaking. If it's the front pump seal, simply yank the unit and replace the seal - put assembly lube or peteoleum jelly on the new seal before installation and trans fluid on the converter hub.

$43 on a friggin pan gasket is a complete waste of money. A simple composite pan gasket (NO CORK) will work fine ($2). Torque all pan bolts to 98 in lbs and DO NOT use any RTV.

If your pan still leaks, the pan and/or pan rail surface is warped and pan needs to be replaced. Buy a B&M or similar aluminum pan if you want - just make sure the new pan comes with a filter extension tube if its deeper than a stock pan.