7.5 to 8.8 Swap

[USMCMiller]

I just swapped my old 7.5 out of my 2000 Ranger for an 1999 Explorer 4.10 8.8 with disc brakes and everything seemed fine but my speedo wouldn't move but when I turned my truck on my brake and ABS light was on. After driving it a second time, my first gear revved until it felt like it was redlining. NOTE: my truck is automatic. It shifted into second very hard and my Check Engine light instantly popped on. I topped off my brake fluid and installed a new ABS sensor in my rear end and the brake and ABS light went off. My speedo now moves sporadically and the transmission is shifting randomly. Going under (I'd estimate) 45mph it runs fine, but after that, it'll seem to downshift, peg the RPMs and launch the truck forward, then it'll free rev like in neutral for a few seconds then upshift and repeating until I decelerate to a crawl. Any ideas? Could it be the tone ring? I can care less if the speedo isn't accurate, but the shifting issue makes me nervous of causing damage.

 

[Captain Ledd]

was the 7.5" a 4.10 axle?

 

[USMCMiller]

I believe it was a 3.73