My '85 240 automatic transmission has begun slipping infrequently and only in the 5-8min after I first start the car. It also only slips in 1st gear out of the hole: I'll give it some gas and it'll hesitate and then catch.

my 240 has a bit under 137k miles. I do not know if the transmission fluid and filter have been changed ever or not. my service records (the car has only one previous owner, my grandfather) indicate there were routine maintenance services at specified intervals, the last being around 75k miles. I do not know if the transmission fluid was changed then or not.

my question is: should I change both? I've read where it's good to change both every 50-80k miles, but if they haven't been changed regularly, it can be bad to change the fluid....

What do y'all think?

 

I checked the fluid level and I was super low. Added ~1.5qrts and will see how she drives tonight. The trans fluid in there currently was a light brown, but didn't appear burnt or like it had metal chunks in it.

However, I fear I have an ATF leak somewhere... will look under the car soon.

 

I'd change it. It's an old wives' tale that a change can cause failure. 137k is low miles but certainly overdue for a change! Sure, make sure that there is no leak, of course.
These are good, reliable transmissions but the fluid should be changed every 50k or so--it's not hard or expensive.