Puffs of Smoke from RHS front side - suspect auto transmission leak on catylitic conv

[floridacatfan]

OK - I need help - this forum is awsome but I haven't been able to find the right solution.

The truck is the 1998 ford exporer XLT 4.0 SOHC with auto transmission.

The symptom is in the thread title. The smell of the smoke is rubber like a hose burning or other. Further investigation convinced me the puffs are coming from a fluid on top of the catylitic converter. I suspect a transmission leak dripping on the converter and burning off. When I clean the converter off the symptom tends to go away.

I'm stumped. Any ideas where the leak could come from. It's more scary than anything. If not for the embarassment I would ignore it.

 

[2000StreetRod]

coolant or oil?

I suggest determining if there is a coolant or oil leak. Oil would probably smoke more than coolant but I suspect either would smoke. Check the front passenger floor mat for dampness. Maybe the heater core is leaking. The thermostat housing is prone to leak. When it does coolant flows aft thru the valley between the heads and then down the rear of the block. Oil leaks can come from the rear main seal, valve cover gaskets or the transmission. You might try placing a piece of cardboard or something similar to determine the type of fluid that is dripping.

 

[floridacatfan]

I have resolved this issue. After much investigation I decided on the oil filter as a target. The oil changes had been done by a local 30 minute oil change. I sourced a proper motorcraft oil filter and put 1.25 turns on it after touching the gasket. Problem solved I think. Inspection of the 30 minte oil change filter did not tell me a lot except the free hieght on the seal fro the motorcraft part was much greater than the 30 minute oil change unit. Could have been due to the set but I don't think so.

 

[Robman]

In this situation, this is where the motor and tranny connect.. rear main seal can't be ruled out in the future.