Ranger 2.9 - 4.0 swap, transmission problem

[lil90red]

Ok folks, I know this is an old, pretty routine swap after all these years but I have one that I just did and have a problem with it.

I have a 90 Ranger 2.9 and used a 92 Explorer donor 4.0. Both trucks were automatics but the trans in the Explorer was bad. I decided to do the engine swap and use the original 2.9 A4LD even though I know it is fairly weak. I will run it this way until I can find a 4.0 A4LD and do the trans swap since I believe the connections will all be the same.

Here is the issue. I used the original Ranger headlight harness which is what everyone says is the best option. I used the Explorer engine harness and PCM. I have everything done and wired and no issues when the truck is sitting in the shop running. The issue is when you put it in gear to drive, the transmission will not shift. It will go into forward and reverse and moves just fine but as you pick up speed the transmission will not shift out of second gear.

On the drivers side inner fender where the transmission harness from the original Ranger comes up, I have tied in the shift solenoid wire from the Explorer harness which is orange/yellow to the Ranger trans harness which is tan/lt blue. Then I have the torque converter clutch solenoid wire from the Explorer which is purple/yellow tied to the Ranger harness wire which is white. I of course have the red wire which supplies VPWR tied in with the main harness connections since it supplies keyed power to a number of other sensors. I assume the way the shift solenoid circuit and torque converter circuits work is to supply ground to the signal wires (orange/yellow and purple/yellow) and energize the solenoid with the red wire supplying power to both solenoids. I have put a meter across each signal wire and the red VPWR wire to see if the PCM ever sends a command for the shift solenoid to energize but it never changes state. I had a scanner connected to the EEC port and the truck is running in closed loop so I dont think there is any issue with it running improperly and being in a limp home type mode. Any ideas as to why the transmission is not wanting to shift? The swap went pretty smooth up to this point but have been working on this problem now for 3 days. I went back and checked all connections, double checked all grounds and all wire splices are soldered, not just twisted wires or jumpers.

I know most of the swaps on here pertain to a 5spd conversion so I was not able to find much on the automatics so thanks in advance for any help.

 

[adsm08]

Throw your meter back in the tool box. Until you get to 4th gear the A4LD is a completely hydro/mech trans. No electronics are involved in the 1-2, or 2-3 shifts. Some of the earliest versions weren't even electronic on the 3-4 IIRC.

Not coming out of second gear sounds like an issue with the vacuum modulator. Make sure that little vacuum diaphragm unit near the bottom of the trans is supplied with manifold vacuum.

 

[jhammel85]

I second the modulator as well. Of course, make sure the fluid level and fluid type is correct.

 

[lil90red]

Thanks for the reply guys. Dead on, I couldnt see the forest for the trees. Tried to make a bigger problem out of it than it was. Vac modulator line was removed when the old 2.9 was removed and never put back on. Hooked it up today and everything is working like a champ.

Let me try my luck with another question. I have the tach wire from the Ranger HH and the Explorer engine harness tied together correctly but the tach is not working at any engine speed. I read a couple of threads about the tachs reading incorrectly due to the DIS from the Explorer but didnt see anyone mentioning it not working at all. The truck is completely stock and still carries the original Ranger tach in the dash.

Any ideas on that one??

Thanks again.

 

[lil90red]

Guys, any ideas on this tach issue??

Thanks in advance for any help.

 

[adsm08]

Connect your tach wire from the cluster to pin 4, DG/Y at the computer. It SHOULD work then. I have my 87's tach hooked up there on the 4.0 computer. I am not sure that it is 100% accurate, but I think it is close, at least to 2000 RPM.