Tranny doesn’t lockup, sometimes.

EricE · 06-20-07, 01:17 PM

I don’t see this as a big problem except if it points to a problem with my transmission. This always happens from a dead stop or extremely slow speeds. I first noticed it when jinking around trying to park a camping trailer and that is usually when it occurs. I had it happen again yesterday when I was stuck in extreme traffic (Start car, move up one car length, park, turn off, rinse, repeat).
I’ll be hard on the gas from a stop or very near it, the tranny will unlock and remain unlocked when reved. When this happens you cannot make the truck go very easily…most of the energy is being eaten up in spinning the torque converter. The truck will move but not match the engine speed. The fix is to just stop, then start again being easier on the pedal.
I recently did a full flush, replace, fill of the tranny fluid and the problem has occurred both before and after that.
It is extremely rare. It happens maybe 3 times a year.

Normal? Anything to worry about?

jonheld · 06-20-07, 01:46 PM

Couple of things pop into my head.

1. Automatic Transmission fluid level. Needs to be checked according to the owners manual or FSM, ie. at normal operating temperature, through all the gears, back to PARK, with the engine running, on level ground.

2. Stripped drive plate on a hub(s). Center diff VC can't react fast enough when you mash the skinny pedal, but can keep it together during slow starts. If you have a center diff lock switch you could try that or shift into low range.

EricE · 06-20-07, 02:49 PM

My fluid level should be fine as I just did the full flush a couple of weeks ago (used the proper procedure for checking fluid level) Besides, the truck has always done it since I have owned it (5 years). Shifting into low range seems the best option if that prevents it. Low gives me good control for parking a heavy trailer anyway.

CJF · 06-20-07, 04:21 PM

Well it certainly isn't normal. Next time it happens I'd try to gather as much information as possible: Is the front driveshaft spinning?, etc...

EricE · 06-20-07, 04:51 PM

Quote:

Originally Posted by CJF

Well it certainly isn't normal. Next time it happens I'd try to gather as much information as possible: Is the front driveshaft spinning?, etc...

Thats what I needed to know. I'll try and replicate it to gain some insight.

EricE · 06-21-07, 09:19 AM

I thought about this some more. All these occurrences happened just after shifting. I am thinking that it *may* be related to the other problem that I have always had which is the shift indicator is flaky. It generally doesn’t show D when in drive. Most of the other indicators work but drive is flaky in that is sometimes shows but most often does not. I think I’ll dig in there and see if I can solve that and maybe it will resolve the other problem.

GeoRoss · 06-21-07, 09:24 AM

Quote:

Originally Posted by EricE

I thought about this some more. All these occurrences happened just after shifting. I am thinking that it *may* be related to the other problem that I have always had which is the shift indicator is flaky. It generally doesn’t show D when in drive. Most of the other indicators work but drive is flaky in that is sometimes shows but most often does not. I think I’ll dig in there and see if I can solve that and maybe it will resolve the other problem.

One place to look is the neutral safety switch harness connector. If there is corrosion you can get these strange indicator issues. Do you have any issues with the trailer harness?

Hayes · 06-21-07, 01:12 PM

You might also look into the shift solenoid issues that have been noted.
Sometimes, if I carelessly and quickly flip the shift lever from Park to Drive, something doesn't quite connect. I get lots of rpms and very, very little go go. I never have the problem if I am more deliberate with the shift lever.

EricE · 06-21-07, 01:16 PM

Quote:

Originally Posted by Hayes

You might also look into the shift solenoid issues that have been noted.
Sometimes, if I carelessly and quickly flip the shift lever from Park to Drive, something doesn't quite connect. I get lots of rpms and very, very little go go. I never have the problem if I am more deliberate with the shift lever.

What you are describing is exactly what I am talking about. So maybe it is a timing issue? Like the truck didn't have time to fully decide I was in drive. hmmm. That is something I can test.

Hayes · 06-21-07, 01:19 PM

Do a search on shift solenoids.
Cruiser Dan is very familiar with the problem--I believe he replaced one of his solenoids. You might send him a PM.

I have decided to ignore the problem in my rig, unless it becomes more common.

EricE · 06-21-07, 08:38 PM

I believe a shift solenoid is likely my problem. Its not a big problem though and I am not quite ready to replace it. </br>
Anyway, I dug into the center console intending to find and fix whatever registers what gear you are in. I tore everything apart and unplugged all the electrical in there but none of them affected the shift indicator. My shift indicator works perfectly on everything but D. In Drive it never works. Where is that indicator sensor? On the Transmission? Is it perhaps the shift solenoid itself? I looked through the FSM but was unable to find the sensor. Anyone know?

NaterGator · 06-21-07, 09:19 PM

Quote:

Originally Posted by EricE

I believe a shift solenoid is likely my problem. Its not a big problem though and I am not quite ready to replace it. </br>
Anyway, I dug into the center console intending to find and fix whatever registers what gear you are in. I tore everything apart and unplugged all the electrical in there but none of them affected the shift indicator. My shift indicator works perfectly on everything but D. In Drive it never works. Where is that indicator sensor? On the Transmission? Is it perhaps the shift solenoid itself? I looked through the FSM but was unable to find the sensor. Anyone know?

I may be misreading what you mean, but isn't the most likely culprit of this a burned out light behind the dash?

The "D" light gets used the most and it would be the one to burn out first

EricE · 06-22-07, 09:10 AM

Quote:

Originally Posted by NaterGator

I may be misreading what you mean, but isn't the most likely culprit of this a burned out light behind the dash?

The "D" light gets used the most and it would be the one to burn out first

That is a distinct possibility and one I'll have to explore. But...the D indicator was flaky long before going out completely which leads me to believe the problem lies elsewhere. When I first got the truck 5 years ago the D would sometimes show and sometimes not. When it wouldn't show I was able to move the shifter back and forth (remaining in drive) and get it to show up. This leads me to think that whatever registers that I am in drive and sends the signal to turn on the light is not making good connection.
Ill do some extensive searching (on here) today and see if I can figure out where/what this sensor is because it sure isn't in the pile of electrical under the shifter housing.

GeoRoss · 06-22-07, 09:21 AM

Quote:

Originally Posted by EricE

That is a distinct possibility and one I'll have to explore. But...the D indicator was flaky long before going out completely which leads me to believe the problem lies elsewhere. When I first got the truck 5 years ago the D would sometimes show and sometimes not. When it wouldn't show I was able to move the shifter back and forth (remaining in drive) and get it to show up. This leads me to think that whatever registers that I am in drive and sends the signal to turn on the light is not making good connection.
Ill do some extensive searching (on here) today and see if I can figure out where/what this sensor is because it sure isn't in the pile of electrical under the shifter housing.

A friend of mine had similar issues, but finally had no indicator lights. In the end it was found that the connector from the the neutral safety switch to the TCM(?) was severely corroded. After fixing this he has had no furth problems. He was also experiencing trailer light issues as well as back up light issues. Fixing the corroded plug fixed these issues as well.

EricE · 06-22-07, 10:26 AM

Quote:

Originally Posted by GeoRoss

A friend of mine had similar issues, but finally had no indicator lights. In the end it was found that the connector from the the neutral safety switch to the TCM(?) was severely corroded. After fixing this he has had no furth problems. He was also experiencing trailer light issues as well as back up light issues. Fixing the corroded plug fixed these issues as well.

Neutral-safety-switch...hmmm. Wasn't that thing under the shifter panel? The area I was exploring last night? I thought it was but I could be wrong. I don't have a FSM here at work. I swear I disconnected everything under there and the indicator lights still worked after each disconnect. Oh well. I'll take a look at the FSM tonight and find the plug for the Neutral-safety-switch. Thanks GeoRoss.

Hayes · 06-22-07, 11:15 AM

A burnt-out "D" light in the dash gets you into an exclusive club--of which I am also a member. It is not uncommon.

GeoRoss · 06-22-07, 01:23 PM

Quote:

Originally Posted by EricE

Neutral-safety-switch...hmmm. Wasn't that thing under the shifter panel? The area I was exploring last night? I thought it was but I could be wrong. I don't have a FSM here at work. I swear I disconnected everything under there and the indicator lights still worked after each disconnect. Oh well. I'll take a look at the FSM tonight and find the plug for the Neutral-safety-switch. Thanks GeoRoss.

Sadly no. You can see the neutral safety switch is accessed from the underside. It is on the DS of the transmission IIRC. There is not alot of slack in the harness and IIRC he had to solder in a new plug as it would be pretty hard to run a new harness to the NSS.

What we think happened to him is that the connector was drenched after a PHH failure, which corroded the crap out of it. I don't recall how his indicators lights failed, but in the end he had no dash transmission indicator lights, no back up lights and no trailer back up lights. He replaced the NSS and that fixed the problem for a short time. Replacing the harness connector fixed it for good.

However, after re-reading your indicator issue my friend (MaddBaggins) had no transmission indicator lights and had back up light issues, yours is isolated to the D light. The K.I.S.S. thing (as mentioned by others) would be more related to the bulb in the dash.

It isn't too bad checking the NSS connector, just follow the wires to the harness plug from under the truck (check FSM for correct location) to check for corrosion. Otherwise it will be tearing into the dash and replacing the bulb.

Keep in mind I know enough to be dangerous and have no clue if NSS problems could lead to the shifting issues you have or if the NSS is the most likely cause of your intermittent D indicator.

Good Luck.

EricE · 06-22-07, 01:56 PM

I have been into the dash lots. I just picked up a replacement D bulb and will do that first. I'll test the light that was in there by switching it with the L, or 2 light (before I put it all back together). That way I'll know if it was bad or not. If I still don't get reliable D indicator then I'll try out this NSS connector.
Thanks again for the info.

landtank · 06-22-07, 02:13 PM

I remember IdahoDoug being able to cause a shifting problem in his 93 and I think he thought it was normal. Well, a normal problem in that it was in all trannies.

If I didn't complete suck at searching I could probably dig it up, but I'll try anyway.

Doesn't appear to be the same thing but you might look through it anyway.

Idahodoug's tranny thread

EricE · 06-22-07, 02:28 PM

Quote:

Originally Posted by landtank

I remember IdahoDoug being able to cause a shifting problem in his 93 and I think he thought it was normal. Well, a normal problem in that it was in all trannies.

If I didn't complete suck at searching I could probably dig it up, but I'll try anyway.

Doesn't appear to be the same thing but you might look through it anyway.

Idahodoug's tranny thread

Nice find Rick. I am thinking this problem is along the same lines. I am able to confuse the Transmision ECU by giving it input it was not meant to handle...Like perhaps on the gas a fraction of a second before I drop it into D. It responds with no tranny lockup. thanks for the link.