TC Lockup in 3rd Thru OD?

[sn0border88]

Recently (this morning) my tranny has been acting up. Initally while under load going up a hill in anything above 3rd it would kind of chug and surge around 2k. It felt like someone was rapidly tapping the brakes. i could see the RPM's drop around 100-200 each time, so I knew something was up. Later in the day it is now doing it everywhere, downhill included as long as its under load. Worst is when its in OD, it feels like a rough shift but is really rapid. I can feel the truck lunge and pull during the surges. Im positive now its the TC going into lockup, I first though it may be bad gas or loose spark wires but I checked them and everything is good, and its been the same tank of gas for over a week now. Is there a servo that is known for doing this and going bad or what? What can I do to fix this, its really annoying.

 

[MrShorty]

Computer can command TCC lockup in either 3rd or 4th gear. If the TCC is locking up when it shouldn't or intermittently, the first thing to check is if the problem is EEC-IV related (bad information from a sensor or something), bad wiring to the TCC solenoid, or if the problem is internal to the transmission. I've discussed this in detail a few times. Basically, start by pulling codes from the computer: resolve any non-pass codes. Then check the wiring to the solenoid: circuit's pretty simple, should be easy with a wiring diagram and a voltmeter. If the electrical control stuff checks out ok, then the problem is inside the transmission/valve body.

 

[sn0border88]

that makes sense, i was messing around with some of the previous's owners wiring mess the other day, and this was the first time I really drove it since then. Where is the circut/solenoid wiring, apart from the transmission its self? I take it there is something related to it under the dash? I know I was at times pulling at some things I probably shouldnt have.

 

[sn0border88]

Just got done pulling th codes, I got code 53(TPS signal low) code 66 (MAF or Trans Oil Temp signal low) and, as figured/hoped, code 89 (TC lockup Soleniod circut failure)

Now that I know the circut failed, how do I go about fixing that problem. Im sure I got something messed up when I rewired everything saturday how do I track down the wire. Does anyone have a diagram or at least the location of the harness that contains the transmission wires? Also where is the lockup sol on the housing, is it accessible to test w/ voltmeter to check if its getting power? Im figuring that when I rewired the trans temp gauge i cutoff the power supply to that circut somehow.

 

[Glacier991]

It sounds more to me like a short. Happening ocasionally, intermittently. The solenoids are in the valve body, which is under the pan. The circuit feeds thru the case connector. The solenoids operate by the computer providing a ground... there is always 12V present.

 

[sn0border88]

its not intermittent, its all the time in the range I gave. And the studders (as im now calling them) are constant, as they were always since the start.

So par from all that, how do I fix this?

 

[BrooklynBay]

First of all, do a continuity check of your solenoids through the case connector, which is located on the driver's side of the transmission. It has 3 wires going into it. One is the constant (V+), and the other 2 are for the TCC, and 3-4 OD. There should be about 26-40 ohms of resistance on each one of them. If you get more, or less than this, you would have to open the pan, and check those parts directly. You have to unplug the existing wiring going into them (red and blue wires) and see if your readings are the same, or different with, and without the external wiring. If it is different, you would have to do a continuity check of the case connector's harness without the vehicles harness plugged into it. Keep in mind that there is a diode internally mounted inside of the case connector which only conducts electricity in one direction.

 

[sn0border88]

so I should get a 12v reading on one wire when the key is on, and the other only have power during a shift or in drive, but I will still get a reading of resistance.

Ok, and lets say that I dont get the 12v reading. Where do these wires go to, the computer on the pass side or the mass of harnesses on the driversside? Also, how hard are the sol's to replace if they are bad? And what do they run (about)?

 

[BrooklynBay]

Check your fuses. If one of them is burned out, it won't let power go into the wires. The solenoids are about $30-$50 for both. They do make more expensive types for over $100. The regular ones are OK, so don't waste money on them. You could try to clean them out if dirt got built up inside of them, but that won't affect their internal resistance.

 

[sn0border88]

Just checked the 3 and 6 wire connectors on the transmission. I got no readings on any wire for voltage or resistance. This was with the key in the on position but vehicle notr running. I took it that the vehicle wouldnt need to be running for me to get a reading. I checked every fuse and they all checked fine. Can someone please tell me where these wires go from the transmission, specifically where the wire that is suppost to have the 12 gets its power from?

A wiring diagram would be key.

Also checked the wires with the engine running, it wouldnt start with the connector off so I re connected it and then just stuck the probe into the wire. I got .15 v? on 2 of the 3 wires and I tried a few times to make sure I had a good ground and a solid connection through the insulation and it never changed. Also got that .15v reading on a few wires when I first check and the truck wasnt running.

 

[MrShorty]

A wiring diagram would be key.

I heartily agree. It seems that the wiring diagrams available in Chiltons/Haynes are adequate for the basic TCC solenoid circuit. Autozone has electronic versions of Chiltons on their website.
Basically, the TCC solenoid circuit looks like: B+ -> EEC fuse -> EEC relay -> TCC solenoid -> PCM (ground side switch) -> B-

 

[sn0border88]

Ive checked my chiltons, theres nothing in there that i can find that will help, im gonna try the online guides at autozone? If anyone has a better link somewhere let me know.

EDIT: I think I found what im looking for, http://autozone.com/images/cds/gif/large/0900823d800ba9d4.gif

says pin number 53 is for the TTC sol and 52 is for the 3-4 shift sol, im going toc check each one for voltage, and if power is there when Key is in on position then the problem is somewhere in between correct?

 

[BrooklynBay]

 

[BrooklynBay]

That red wire is the feed from the EEC relay when the ignition is switched to the accessory position. You should have a positive voltage on that wire. Check that wire with a test light, and ground the other end of the test light.

 

[BrooklynBay]

Did you check the 30 amp fuse in the power distribution box? That relay is controlling a lot of parts, like your injectors, idle air control valve, canister purge solenoid, etc. If that circuit had no power, you wouldn't be able to start.

 

[sn0border88]

just checked all the fuses again, all checked fine. 12.5 volts through everything. I ran a wire from the neg - terminal of the batt down to underneath the truck so I knew I would have a solid ground for testing (I have had grounding problems lately) I checked the 3 wire harness again and this time I got 12.5 at the middle slot, so I must of had a bad ground before. I still havent gotten a reading for resistance yet, it just stays at OL.

So now that I know im getting power, the problem is more than likley the sol its self I guess? Whats its like replacing it, is it just on the VB or is it more intensive than that?

 

[BrooklynBay]

The solenoids are connected to the VB. You should first check the solenoids for resistance before dropping the pan. If you are going to drop the pan anyway, then you should check the internal harness (case connector) for continuity.

 

[sn0border88]

as for checking for resistance, I have never checked for that before so I just want to make sure im doing this right. I set the multimeter to OHMS and attatch the positive lead to the slot to be tested and the black lead to a ground correct? If so, Ive tried this a number of times and each time the multimeter just reads OL.

 

[BrooklynBay]

That is not correct. The 2 internal solenoids have a common lead on the case connector in the center of the connector. The 2 other pins on the connector go to the 2 solenoids. You are touching the 2 tips of your meter to the 2 ends of each solenoid. The reason that you have 3 leads on your connector is because one is the common lead.

 

[BrooklynBay]

According to the above diagram, you would be testing both sides of the solenoids, which would be red-ppl/yel (53), and red-orn/yel (52).