1985Beater

I bought a 1985 f150 2wd with the i6 and I'm assuming the 3 speed? Only drove it the first night I bought it back in November, 60 miles back to my house, motor needed a little work but the tranny was working fine and was rebuilt this past July.

i finally finished up all the bodywork and paint, threw the wheels on her to wrap up the exterior of the truck.. upon driving it for the 2nd time, the truck won't shift out of first.

i have two questions:

1) I lowered the rear end with lowering shackles two inches, would that have anything to do with why it won't shift?

2) The blinkers did not work, the harness behind the steering wheel where the blinker arm connects was shot, I replaced it with a junk yard pull from an 83 f150. I noticed there's about 20 wires running threw the harness, which seems like over kill for blinkers and flashers, could that have anything to do with it?

its just odd to me the fact that it worked fine, sat for 4-5 months and now it won't shift.

Any thoughts??

Braggs

Lowering causing shifting issues? Not likely. Worst you're gonna do is cause extra wear on the U-joints from changing the driveshaft angle. That's why you see the rear axle angled more upward on lifted vehicles, to reduce the driveshaft angle.

The I6 in 1985 is computer controlled but they didn't start including the electronically controlled E4OD until 1989. That means unless the previous owner changed the transmission, then you have a hydraulically controlled transmission, not an electrically controlled transmission. Wires behind the dash would have nothing to do with shifting on a hydraulic transmission.

Ok, now that the history is out of the way, what could be causing the shifting problems? Here's a list of things from easiest to hardest to fix. Some are unlikely, others are more likely.

• Loose/Misadjusted shift linkage (easiest to check, do this first)
• Loose/misadjusted band adjustment (did you see the other post of the guy whose band adjustment nut came off and the bolt was missing?)
• Vacuum leak (there's a vacuum hose going to a vacuum modulator on the back of the transmission that controls shift points, etc)
• Stuck valves or broken valve springs in the valve body (difficult to repair, check this before the governor)
• Stuck governor valves (less likely, harder to repair)
• Worn clutches (this happens over time and will require a complete rebuild)
• Old/worn/cracked seals. (This happens with age and will require a complete rebuild.)

burnthelight88

Dude above me really gave you a ton of suggestions, but I'd just like to place a bet on the vacuum leak to the modulator.

Chris_1

iTrader: (1)

If it shifts after it's really warmed up well a good bet would be the governor. It's been a while so bear with me, but one version (AOD ?)had a governor that you could get to by pulling the tailshaft housing (or transfer case on 4x4).
That particular setup was prone to the governor sticking and holding it in first especially when cold.
Sonnax makes a heavier weight for that particular governor that solves that problem pretty well.

1985Beater

Thank you for the responses. The fluid is topped off, checked it and added accordingly while it was running. Was only a 3rd of a qt low. It will not shift out of first running cold or hot.

There are wires running to the driver side of the tranny from the firewall. Idk if this eliminates the shift points being vacuum controlled or not. The harness and wires appear to be new or added after the rebuild, a lot of electrical tape jerry rigging lol



And is this the vacuum modular? lol I'm a noob to transmissions. When the truck is running, after it warms up, I can hear a whistle/humming sound coming from underneath the cab, would this sound be consistent with a vacuum leak maybe?



Thank you all for your help and suggestions. This is just a project of mine and I'm in no hurry to fix it, I'd definitely want to do it myself, love learning new stuff.

Braggs

The wires you are seeing are a neutral safety switch. They make sure you can't start the vehicle unless it's in Park or Neutral. If you can start the vehicle, those wires are fine.

Yes, that's the vacuum modulator. It should have a vacuum hose hooked up to it. This hose will go to a metal tube that goes up into the engine compartment at the back of the engine. Then another rubber hose will connect it to the vacuum distribution block.

The hissing sound may lead to a vacuum leak, or it might just be the carburetor sucking you're hearing. Still, you should try to look for leaks. Someone suggested using a cigar or cigarette smoke while the vehicle is off and blowing the smoke through the main vacuum hose that connects to the front of the carburetor. You can connect another hose to it so you don't have to crawl into the engine compartment.

1985Beater

Good to know! The sound is definitely not coming from the carb, and it's not a hissing sound. To describe it as accurately as I can; if you've ever left a door open on an older car with the ignition off and keys still in it, it'll make that non-stop buzzing sound until you remove the keys. The sound I'm hearing sounds oddly similar to that, but airy, and it's coming from under the cab toward the back of the engine bay.

AND the sound didn't start until after I got the truck home and moved it around the property a bunch when I was doing the body and engine work, so I'm betting a hose was dry rotted or something and it gave way.

Now to just pin point the leak, which I bet is connected to the modulator. Fun stuff. Lol

1985Beater

I took a video of the sound it's making, it's coming from the tranny area for sure, can't see much but you can hear it, I'm laying under the truck recording this.

https://youtu.be/7b8MtaP5KUk

I dont know how to embed this on mobile.

Braggs

That is a strange sound. And it does sound like a warning buzzer in the cab like you said. I don't know what could be causing such a noise under there.

Yes, aging vehicles need anything that's rubber replaced. You can tell if it needs to be replaced by how it looks and feels. If it's hard, cracked, or turns your hand black, replace it. On my pickup this meant other stuff too, like o-rings (distributor shaft), clutch piston seals in the transmission, and door/window seals.