I had the 4-speed automatic transmission in My 1999 Ranger 4x4 Off-Road rebuilt in December of last year at a reputable area transmission shop, and a few weeks later, I noticed when it's cold outside that sometimes the truck shifts really hard from 1st into 2nd gear. I had the shop look at it, and they didn't see anything wrong in the shifting on their scan tool. The hard shift seemed to go away when the weather warmed up for spring and summer, so I assumed it was something to do with the transmission breaking in, as it otherwise shifted excellently. It was a chilly day today, and this hard shifting happened twice within the first two minutes of driving. The 2nd time wasn't as harsh as the first. There is no sign of slipping, and the shift timing seems to be correct with the RPMs/ truck speed. What could be causing this hard hit into 2nd gear when it's cold? Once the truck has somewhat warmed up, it seamlessly shifts through all 4 gears the rest of the time it's being driven. I have another month on the 12 month warranty for the work, so I would like to get it fixed if anybody has any idea on what could be causing this. It doesn't appear to be fluid level related, as the fluid isn't low.
Well obviously they didn't rebuild it correctly it wouldn't have problems in cold weather shifting like that it's probably a very tiny thing that was done wrong but I doubt if they're going to stand behind it unless when it's cold out you can leave it to them overnight and they can see that it's just poorly make a point of being there yourself because tranny guys never want to do a job over to giant pain and they lose money
If it under a year old it should still have warrenty on it either 12 or so many miles if it shifts ok when its warm it could be yhe wrong oil or realy dirty oil try changing oil and filter first as this is yhe cheapest option
I started using my phone on Tuesday night to record my first minute or so of driving to see if I could get lucky and catch the hard shift. I was able to catch a hard shift today, the RPMs reach 2500, there is a low pitched thud, my phone shudders, and the RPMs drop back down below 2000. Are we able to post a video on here? I can share the video so the sound and driving can be seen. I contacted someone in the shop's main office last night, and the manager of the store reached out to me today and said to bring it in next week, they'll look at it again, so I'm going to do that. Will the video be of any use to prove to them something is wrong?
In the meantime, I've heard that a failing Throttle Position Sensor can cause harsh, and or poorly timed shifting. I cleaned my throttle body over the summer after watching Scotty's video on the subject, and it was so carboned up that the engine didn't start the first time I cranked it over after cleaning it out. It caught the 2nd time and ran like crap for a little bit before smoothing out, so I'm assuming my TPS may be the factory original based on the fact that the throttle body was so filthy. That would mean it has 21 years and 260k miles on it, so it may be worn. I bought a new Motorcraft TPS today and will be installing that tomorrow. The CEL has never come on to indicate that it is bad, but given that temperature shifts and age can mess with electronic sensors, I figure it may be worth a try.