my 1999 F350 Powerstroke transmission has been rebuilt. The mechanic said he put better aftermarket parts in and stronger springs. I notice from time to time when it shifts down and then back up, when pulling a hill, it slams up hardwould that possibly be because of the stronger springs he installed?

 

Yes, that's possible, even likely.

 

I too just had my 4r100 transmission rebuilt. The shop also put in a new torque converter and a "mild" upgrade kit kit plus the most up-to-date updates for my transmission. It shifts harder/crisper than before under certain conditions. When I returned for my 1 month follow-up check (driveability, code scan and leak inspection etc.), the shop owner road tested it again and said it was performing as designed. Hope this helps.

 

Thanks. I was hoping to hear that

 

Thanks. Sounds like I was just a little worried for something normal.