My car is ford Ef 1995 fairmont. When the car is cold , it drive well. when it is driven for around 15-20 min, it is very low power to run at the first gear( 2 and 3 is fine) I think this will happend when the car is hot. someone said this is a gearbox problem.

I have checked the trammission oil it is black but I Just done the tranmission service for last few days. THis should be a red colour right?

too much burn in gearbox? or something wrong?

1. How can I solve that problem? change a new gearbox or just change new oil and filter again?
2. How much for repairing it?
3. Could anyone advice me for the reliable service centre around northcoth(3070) VIC .
4. Or install the transmission cooler , Can it help ?

my car is 210,000 km at the moment

Many thank for any suggestion

my box killed 2nd at 275,000 its serviced every 20,000 or yearly,i had a minor rebuild at 195,000 when i bought it-warranty from car yard.it runs a oil cooler.you may have to flush the oil with motor running for a few seconds as the radiator and torque converter are still full of old oil, problem is old oil hardens the oil seals and gives problems--------at the ks the box is at a new-second hand one may be better option.new reco box $1000-1600 check if it includes fitting and extras, or 2nd hand and you fit it.ebay.