Transmission question

[1qwikSS]

Im in the works to try to buy my gf's parents truck off them so she can have something better than a mustang to drive this winter. The truck is a 2004 (i think) ford ranger 4x4 ext cab auto transmission. only has around 40,000 miles on it and it has been sitting in there driveway since the beginning of last fall due to slipping of the transmission.
So i got talking with her dad yesterday and he said the truck only slips in 2nd gear, after the engine has warmed up. he said he remembers seeing antifreeze leaking out of a crack in the plastic on the radiator last year when it started having problems. we took the radiator off the truck and inspected it for cracks but could not find any. Also there was a grease buildup where the transmission fluid lines hook into the radiator. So my question is do you think its the transmission that needs fixed or maybe the trans fluid is getting too hot due to leaking radiator and its slipping that way.
Ive had 2 automatic transmission go on me and both of them started slipping in reverse first, then 4th, 3rd, and 2nd. I just find it weird that it only slips in 2nd gear. Any other ideas or thoughts besides these? Thanks.

[Bad_Z28]

Some transmissions don't even have trans coolers. So even if the line was plugged right off, and not cooling at all it still seems like the trans would still shift okay. I just wouldn't tow anything without a trans cooler.

[1qwikSS]

well it has the air conditioning fins, the radiator fins for the engine, it has a small set of fins i believe for the front axle (thats where the lines look like they lead to), and it has a small set of fins that i believe cool the transmission fluid when its engaged in 4x4. I dont know a ton about 4 wheel drive vehicles, but the truck had like 4 sets of fins to cool stuf off.

[sman]

Probably has a tranny cooler in the radiator, and the front set is probably an engine oil cooler.

[bumpin_z]

My monte is in the shop right now. it would slip between 1st and 2nd but intermittent. They said it was either the valve body or the p/n.s. switch. It is looking like the switch is bad. Don't know if it helps you at all but threw it out there for ya!

[sman]

My monte carlo did that too, the 4t60e is a POS tho.

Although, after rereading, im kinda wondering if the coolant and trans fluid mixed, have you checked the fluid, smell burnt? Bright red? If you actually put it in 2 does it slip?

Honestly, id talk to ridings about it, he mentioned to me that ford makes some seriously nice/strong shit in the trans dept. Ill bet he knows whats wrong.

[MP81]

All this talk of trans coolers make me wonder if I have one. The Cobalt autos are V6 trans, I do believe.

[1qwikSS]

yea i always thought that ford's tranmission's were awesome (my company had an early 90's f-150 truck that went like 220,000 miles with original motor and trans, and my 4 banger merc tracer has 190,000 with original motor and trans). I dont think its the transmission especially with only 40k miles on the truck. I told him to replace the radiator and see what happens. There's no reason why it should be leaking trans fluid or antifreeze.....but no i smelled the trans fluid and it didnt smell burnt and it wasnt even low on the dipstick, but there was grease caked all over the transmission fluid side of the radiator. im thinking the trans fluid is just getting too hot to function properly.