Ok, I bought my new project and it has been swapped from a 727 to an overdrive tranny. It kicks into overdrive too early, at 35 mph. Is there a way I can adjust it to shift later or install a switch or something to lock it out until I get on the highway? Has anyone dealt with this? Any help would be appreciated. Thanks.

 

35 mph sounds like the converter lockup. What is it in and what are you using to control the overdrive now.

 

It's actually in an 85 Ramcharger. I know I know, wrong section, but for my application, you guys seem like my best bet, since it's a performance truck, not an offroad vehicle. It's carbureted, with no electronics. Originally it came with a 727, but someone before me swapped in an overdrive tranny. I have absolutely NO control over the overdrive, other than driving slow below 35 mph to keep it from kicking in.

Also, and this may sound dumb, I'm still learning, but isn't the 518 a 727 with an overdrive bolted onto the backside? Is it possible to purchase a performance 727 and swap the overdrive unit over? If so, any particular version of the 727? I hope that question wasn't too dumb.

 

Both the overdrive and lockup on a 518 are inguaged electricly. So with out power to the top plug on the trans it will not go into overdrive.Look on the passinger side of the trans to see if there is a pressure switch screwed in to the side of the trans close to the joint between the front and rear section. The 518 has 727 guts but the case is different on the out side.