My truck is an automatic. It's a 1999 with 125k. Not sure if it's an original tranny or what...

Sometimes it will bump from 1st gear into 2nd. Sometimes it's very smooth, sometimes a little bump, and sometimes it will shake the whole truck. Every other gear is smooth as can be... but every once in awhile it will be pretty bad.

Are there any fluids I can use to reduce this? Any information?

Thanks.

 

my 97 has identical mileage to your and is doing the exact same thing...except its a HARD bump every single time it shifts up from 1st > 2nd
i bought some SeaFoam "Trans Tune" stuff and tomorrow im gonna put it in, as per the instructions, and change out the tranny fluid. I'll reply back and let you know if that changed anything

 

Thanks. I know Lucas makes some treatment as well. I'm sure there's some other stuff out there. If it gets any worse I'm going to try whatever treatment is the best out there, as well as a fluid and filter change.

 

Just from my experience with these trucks, it seems like a pretty common occurrence of the "hard shift" phenomenon between 1st and 2nd; especially with rebuilt transmissions.

I've heard nothing but good things about the lucas transmission treatment stuff, I put it into a 5.0 Mustang I had once with a slipping tranny and afterwards I didn't have any troubles, I've also heard its a good cure for hard-shifting.

 

just got back from the shop...and man that trans tune works wonders!
put in almost the full can and drove it 6 miles to the shop and nothing changed. after they dumped the pan the guy started telling me about how bad additives are and everything but after they were done and i drove away it shifted completely smooth into 2nd
he said it smelled like brake fluid like from a stop-leak, but my guess is the previous owner had put some in. but anywho, now it shifts like a champ!

 

Did your tranny wonder-man say that he may have found a broken spring in the 1-2 accumulator? A very harsh shift into 2nd is characteristic of a bad accumulator usually caused by a broken spring. It's easy to fix and does wonders for the shift quality.

 

LOL at 'wonder man' haha
no, he didnt mention anything like that....but he did say that a common problem with fords is the "vehicle speed sensor" in the rear end
they were swamped today but he said to bring it back next week if i wanted him to check it out more thoroughly, but i guess its fine the way it is now