matt0106

Hello, guys. I am a newbie and a new Jeep owner. So cut me some slack. But my Jeep's transmission is doing weird stuff. It won't get any power when I put it into drive. But I can almost spin my wheels when I manually put it into first gear. So what I'm trying to say is that it doesn't work in drive, but it does work when I manually shift into 1st and up.
Would anyone perhaps know why?


P.S.-I looked around on the internet for a little while and found a few suggestions. And the TPS was one of them. But, I know that's not the problem because we replaced it.

P.S.S-I have the I6 engine and the AW-4 tranny. It is "part-time" 4WD. The "Command-Track" if I'm not mistaken.

cruiser54

First off, we're cutting you no slack!! Up under the glove compartment on that trim piece is your TCU. Transmission Control Unit. In the wiring harness near that, with some yellow tape around it, is an inline fuse. If that fuse is blown or corroded, the TCU won't let the trans start out in first gear. Pull it out and give it a good visual inspection. Check that first and report back.

DFlintstone

A different angle on the same thing. Make sure it's plugged in also, and I'll wager next you will check the wires going down behind the dipstick.

cruiser54

Yep. Good photo and thanks for it.

sthon

I probably don't have to ask this, but have you checked your ATF?

matt0106

I checked out the fuse. I pulled it out and it just fell apart. Looked at it, it was all burnt and melted. Checked the fuse holder, wasted. Replaced the fuse holder, put in new fuse. Started the Jeep, backed out of the driveway, put it into drive, and took off. Just like it's supposed to.

Thank you guys so much.

NorCalJeep

Easy fix. My Jeep did the same thing first month I bought it.

DFlintstone

Hey Great! And the crowd cheers! Well done.


Hope it was a fluke that it failed

cruiser54

Don, I stole your photo....

DFlintstone

That's partly why I crank out so many Pete, hoping people can use them. (it's the same one from the shift-override switch thread I did last year, you have seen it). Those cuts are where you tap in the switch.

That and:
After you cut the yellow wire, the end that goes to harness, (Jeep), goes in the middle of the switch. From there it's REALLY hard to get it wrong.
(taping into the purple/white provides the 3rd)

Actually tells the whole story. I think sometimes when I put things in a nut-shell, people just see a nut!

jchat

Im actually having that same problem with my 96, but mine doesnt have the fuse there. Its just a straight wire up to the firewall then to the electrical connection. Im stumped. Not to thread jack or anything. I started a similar thread but no one is really responding to it!!

DFlintstone

Bummer jchat. Yea, myself and a few others get more interested in the 90 and earlier Renix. Yours stores codes they might read free at the parts store. Since yours stores codes they might read free at the parts store, it makes it less of a puzzle!
You slip taking off in drive? Of course you checked fluid. You may well have the TCU fuse..either under there somewhere..somebody might have even posted, on, the, LEFT, under there. Actually that seems prety rare...something needs to blow it, and the mice are not yet through my trany case...

You might research that fuse, and check the wires, and wiring connections behind your dipstick, down to the trany control solenoids.

67 GMC

Still troubleshooting a TPS that seems ok. I posted the results of my testing on another thread and it looks within spec but intermittently, I will get a no shift out of first problem. As well, sometime, if I'm going 35 MPH and let off the gas, the problem returns when I try to accelerate. The problem is high RPM but speed only 25 MPH or so. I had another TPS from a buddy's part bin but we didn't know if it was bad when pulled. I put that in and it drove pretty much the same as the one it replaced and the test results were nearly identical as far as voltage on both TRANS and Engine side. Not sure that helps.

With the TCU fuse out, the Jeep seems to drive ok in D although I don't see any difference between D and 3. Only been driving around the block here (no high speed) so maybe it won't be able to get a move on like that.
Does that make sense? How can it shift without the TCU?

Frustrated now.

cruiser54

Good possibility your TPS is bad on the "trans" side.

This sure couldn't hurt:
Cruiser’s Trans Plug Refreshing

Over near the trans dipstick tube are 2 rather large connectors. One is black and the other gray. These 2 connectors carry all the info between TPS, TCU, NSS, speed sensor, and trans solenoids.
Unplug each one, visually inspect for corrosion or bent pins, spray them out with electrical contact cleaner and plug them back in.
Revised 3-28-2012

67 GMC

The trans connectors looked ok. Got a new TPS on order for this week. Can you drive with the TCU fuse disconnected? Curious.