Lincoln

I can drive all day without any issue but as soon as I hit 220 degrees for my transmission temperature I get a P1870 code and I start getting a hard shift from 1st to 2nd only. I've seen the TSB #01-07-30-023A and I already had an aftermarket control valve body with larger valves installed. Any ideas on what the problem is?

Thanks.

Mike Mercury

have you changed tire sizes; or rear axle ratio?


There's also the chance your torque converter is slipping - and/or not locking.

Lincoln

Thanks for your reply. I did get new tires but they are the same size. The torque converter was already replaced and that didn't fix the issue. I started having the issue after I had some new transmission seals put in to eliminate a minor leak.

soggysailor

there is an update for the TCC valve in the valve body. do you know if the replacement valve body you got had the update? I had similar issues and the update fixed my problems

Mike Mercury

the P1870 code simply says "in 4th and with the TC locked... the measured engine RPMS are not within proper range".

In most cases it points to:

* slippage in the drivetrain
* rear tire heigth altered too-far from factory specs
* rear axle ratio changed

the last two can be fixed with a reprogram.