A4LD 86' Torque Converter not locking - 4000 rpm at 65mph - wires reversed?

[afdfirefighter]

I have a 1986 Bronco 2 that I just had the transmission rebuilt in. It runs great and shifts great. I was going down the road today with the cruise at 65mph and I was at 4000 rpm. I called my Dad (who has been a mechanic for a very long time). He said put your hazards on and the rpms should go up. I did that and they went down. He said they should not have done that.

He thinks the torque converter is not locking because the two wires a may be backwards. Has anyone ever experience this or anything like it?

Any ideas of potential problems/fixes? Thanks in advance.

 

[MrShorty]

Torque converter clutch will usually only reduce engine speed a few hundred rpm. 4000 rpm at 65 mph suggests to me that the transmission isn't upshifting correctly. It's either stopping in 2nd or 3rd gear. Next test drive, count the number of shifts you can feel. Maybe try manually upshifting (start with selector in 1, then upshift to 2 and see if it responds, upshift to 3 and see what happens, and so on).

Assuming the transmission rebuild came with some kind of warranty/guarantee, I'd probably then take it back to the shop that rebuilt it and ask them to double check their work.

 

[afdfirefighter]

I was talking with may dad some more before I saw this post. Let me tell you what he said first and what I did on next test drive. The indicator panel light for my right rear brake light started flickering on the way home from work tonight but the brake light is still working. I tried holding the speed at a constant speed and tapping the break to activate the brake sensor and my rpms stayed the same. Would this be Indicative of a bad tach? He doesn't seem to think its reading the right rpms to begin with. What are your thoughts after the new information? Also, I do believe I am getting all of my shifts. I will count tomorrow however.

 

[BrooklynBay]

Did you check the TCC solenoid & wiring?

 

[afdfirefighter]

Did you check the TCC solenoid & wiring?

Besides the obvious breaks in wires or disconnected wires, what else would you suggest I be looking for? Thank you for the reply.

 

[BrooklynBay]

Disconnect the plug on the top of the transmission, and connect an Ohmmeter to the contacts. You should see a reading between 25 - 40 Ohms.

 

[afdfirefighter]

Update:

I pulled a trailer with a four wheeler about 30 miles one way today. The tach read about 4500 rpm at 65 mph highway with cruise set. something just didn't feel right. Got home and pulled into the drive and there was tranny fluid everywhere. It was overheating apparently and it was venting out the top. I ran the codes on the check engine light tonight and got these:

-Vehicle Speed Sensor problem - VSS
-ALL - EGR did not open/ respond during test or if memory code, did not open intermittently - EVP EVR PFE
-System lean - Fuel control

The fuel control is because my O2 sensor is unplugged and i can't find the wires leading to the main harness. I did discover that my vacuum line to the vacuum modulator was disconnected. I connected it. Would this be a reason why my tach is reading so high or do i just have a bad tach maybe?

 

[BrooklynBay]

Did you check to see if the modulator had a blown diaphragm? I hope that you weren't towing in overdrive.

 

[afdfirefighter]

Did you check to see if the modulator had a blown diaphragm? I hope that you weren't towing in overdrive.

I did not check the diaphragm only because the modulator is only a month old. Should I do that? The vacuum hose came off because the hose is too large of a diameter. I am going to go get the right diameter before I drive it again. And I was in OD I am not an expert (obviously lol) but shouldn't I be in OD pretty much anytime I am driving?

Also, would the modulator not hooked up make my RPMs higher and not give my 3/4 shift?

 

[BrooklynBay]

You should be in overdrive most of the time except when you tow. The extra strain of towing or hill climbing in overdrive will cause it to jump in & out of overdrive. This will create excessive friction & heat which will cause the front seal to blow out. The modulator regulates the shift pattern.

 

[afdfirefighter]

Unfortunately I was pulling in OD. I added 1.5 qts of fluid to it last night to bring it to full again. Do you think I would have a bad (brand new) vss? That is One of the codes.

 

[BrooklynBay]

I reread your other post which said that the O2 sensor is unplugged. Plug it back in, clear the codes, then see which codes come back.

 

[afdfirefighter]

I reread your other post which said that the O2 sensor is unplugged. Plug it back in, clear the codes, then see which codes come back.

Do you know where I can find pictures/diagrams of where I can find the beginning of the wires for the O2 sensor? I believe they were cut somewhere upstream and I have been unsuccessful on finding the wires to plug it back in to the wiring harness. I am not sure why this was done.

 

[BrooklynBay]

They are coming from the PCM connector.