My 2001 Ram has always shifted a little bit early for my liking. I recently put bigger tires on it, and now it REALLY shifts too early for my liking. Is it safe to adjust this using the TV cable, is there a better/more proper way, or am I just stuck with it doing what it's doing? For what it's worth, the new tires make the speedometer off by right at 10%. If there's a way to fix that, it should also return my shift points the where they were. Thanks in advance for any advice...

no "expert" by any means, but isn't there a "pinion correction" the dealer can do with a factory scan tool ? i remember seeing that in newer FSM's, but i don't remember [if i even knew in the first place] when this started. i believe this was to account for transmission replacement and tire sizes.
john kunkle would know for sure ! he is a transmission GURU. member transman is also, so hopefully either of those gents will chime in and set this straight with the correct info.

RE transmissions use an electronic input to read shaft speed and using that it compares that TPS readings and such and using an algorithm determines when to shift.

Using the TV cable to adjust shift points offers little change and is not what it was intended for.

You need a scan tool that allows you to go in and change the tire size. That’s the correct way to do it.

Hemifever Tuning can make a 'custom' tune for your computer that'll change the shift point RPMs as well as the torque converter lockup RPM.

One weird side-effect is that the raidator fan seems to kick in much more often... not sure why.

-Ben

https://www.hemifevertuning.com/SCT-p/sct-can.htm

Thanks to all for setting me straight. It's mostly that lock-up speed that kills me. I'd be ecstatic if that could be moved up. The other shifts I can live with. I've been conversing with Ryan at FRP Tuning, and plan to get one of his tuners. He has 2 devices to choose from; SCT and SYKED. I'll have to make sure whichever one I go with has the capability to input tire diameter. Thanks again!

Keeps the temp down to 180*. Part of his performance tuning.

Make sure the kick-down cable is adjusted properly, seems that as they wear they don't pull the lever back as far as they used to, almost every trans I re-build for these needs the cable tightened up to get it where it belongs afterwords. We also do it with a tranny service and most of them need to be a little tighter also. With a loose/worn setting it will let the trans shift a little earlier than it should as well as softer than it should, lots of worn tq flights shift way better after a trans service including band and cable adjustment and I always turn the line pressure screw about two turns more pressure to compensate for a little lost tension over the years. None of this makes higher than stock shift points but rather makes sure it is at least right before you go to altering things.

Great to know. Thank you HotRodDave! It does shift a little soft, but I'd kind of expect it to as it's no hot rod. I have a FSM so I'll check it out for sure.

Agreed and good point.

is this the "pinion factor" thing i remember ? or does that term have to do with gear changes in the rear ?

Been awhile, may be one in the same.

See if you can find a diablo sport or hypertech tuner used from ebay or somewhere. It will allow you to adjust shift points ,tire size. rear end ratio and get you a few extra horse opower at the same time. Check them out and see what all they can do.

I agree with this. I have seen a trans guy overhaul a trans and then asked me why it still shifted to early and would even flare a bit on the 1-2 shift at light pedal application. I had to adjust the trans throttle pressure as it was to low (cable to loose). Once we adjusted the throttle pressure cable it worked fine.


From what I remember the only think the pinion factor did was set the speedo to be right and did not change trans shifting. You would set the tire size in RWD trucks in the ABS module as it used the RWAL (Rear Wheel Anti-lock Brake) module for the speedo as it used the speed sensor in the rear differential for the speedo. To have it read the right speed it had to have the right tire size programmed in the ABS module. I also remember if the customer put a tire size on that was not a selection in the ABS module then we had to set it by the tire revolutions per mile. It did not effect shifting of the trans as the trans would use the speed sensor in the trans output shaft housing to set gov pressure. Changing the actual tires to a different size can change the shifting but not setting the pinion factor in the ABS module. All trucks had the RWAL (rear ABS) standard on them. Ron

thanks for the pinion factor explanation ron. [now if i can just remember that ....]