Tranny not shifting from 3rd to OD

[bronco611]

I just replaced my a4ld on my 93explorer with a junk yard a4ld from a 94 model. Everything went well and when I drove it ,it shifted perfect through 1-2-3 and then it would not shift into OD. I replaced all fluids & tranny filter prior to driving. I left the old modulator valve on and used it, could this possibly be the problem? It shifts smooth and strong through the gears even it accelerating hard, no slipping or other issues have occurred. I hope it is an easy fix and that I do not have to pull it again. I just looked at the old filter and the new one I installed didn't have the 2 o-rings on it to seal it to the valve body. Going to the parts store because they were not in the box either. Could fluid leaking around the filter cause a low pressure issue and create this problem? Just go thru pulling pan and filter and boy do I feel like a dummy, the o-rings were there. Put it back together , swapped the modulator with my old modulator and still same as before , will not shift from 3rd to OD please help I am stumped.

 

[MrShorty]

3-4 shift (as well as the torque converter lock up clutch) is electronically controlled by the PCM. Where this is a recent installation, the first thing I'd suggest is to make sure the 3-4 shift/TCC lockup connector got plugged in. If memory serves, it should have three wires and be on the driver's side going into the valve body.

 

[bronco611]

Mr Shorty, glad to hear from you. I went out and checked the connector and evidently I never completely seated them together. Plugged it in and is shifting fine now. Thanks for the input. Mike.