Hello,

I have 1996 discovery. The trans does not upshift after 15-30 minutes driving in the morning. The engine runs fine, there are no trouble codes... The trans fluid is at the proper level.

for the first 15-30 minutes in the morning, it upshifts fine even when going 55mph.

after that it downshift sometimes to 2nd gear or even 1st gear even at 40mph and will stay in that gear.

Sometimes when going 40mph and it has downshifted into 2nd gear, I put it neutral and them into drive, it will upshift to the proper gear... but after about 5-10 minutes it will again downshift into 2nd gear.

If anyone can offer any advice, I would appreciate it.

Thanks,

Harry

 

obviously heat is the issue here..check transmission cooler, make sure it's cooling properly

 

I agree a heat and or clogged filter issue.
I assume the trans temp light is not on?

 

Have you ever dropped the tranny pan and replaced the filter?