We have a four wheel drive 95 GMC 1500 pickup with 142,000 miles and an automatic transmission. When the engine temp reaches a normal operating temp, the transmission won’t shift into first or fourth. When we checked the transmission fluid, there were quite a few air bubbles on the dipstick. I took it in and the mechanic said the transmission needs to be replaced. Does this seem reasonable or is there a less costly alternative? Thanks.
Air bubbles means the tranny fluid has been foaming, likely because the tranny is over-full.
This MAY be due to a coolant leak into the tranny fluid cooler (within the rad).
Not being a tech I’m wondering why it doesn’t act up before the engine gets up to operating temp.
How is reverse working?? How is the level of the ATF?? Are you checking it HOT and on a level surface?? Can you be a little more specific about the symptoms…
It does sound like you are out of luck, in my experience which does not involve transmission repair. When it warms up and doesn’t work, but works when it’s cold, you have a big chance of needing the works.