Shifting Into Drive

AppleJack

Active Member
Hello All,
In the last week or so, I've noticed that Intermittently when going into gear, the display shows I'm still in N. I can drive out but it seems as though I'm in some sort of limp-home reduced power mode.

Physically shifting into neutral and then back to drive cures the problem and the display now shows I'm in D again. No DTC's when I checked.

Is this problem common? I'm showing 202,500 on the odometer and have a refurbished transmission since 200,050 miles back in December. Or is the problem with the shifter itself?

Thanks in advance...
 

Blckshdw

Moderator
If you can, get under the truck and see if you can get your eyes on the linkage between the shifter cable and the transmission itself. There's a plastic bushing, that can sometimes crack/break. Usually when this happens, you lose all shifting functionality, as the cable comes completely loose. You could possibly be seeing the preliminary signs of that problem. There are plastic replacements, I opted for a metal one when mine broke.
 

Maverick6587

Well-Known Member
@Blckshdw I went searching through all the standard sites amazon, rockauto, oreily, autozone, advance, and napa. I did not see any options for a metal bushing. Do you happen to remember where you purchased the metal one from?

I haven't looked at that linkage yet, but I'm sure it's due for a change. I'd rather throw metal rather than plastic at possible problem.
 

Redbeard

Well-Known Member
Some years back when I thought I had this problem I found this on the web.
https://shop.simple-engineering.com/product.sc?productId=94.
I haven't tried it, but it seems like a good solution.
Our Products >> Transmission Shifter Repair Kit





Transmission Shifter Repair Kit






Designed and made Famous by "The Dicktator" in Florida, this repair kit is intended to repair a broken shift pivot connection at the transmission shift arm. The hardware is simple and the installation easy. You simply dismount the existing shift arm from the transmission, drill off the stud that goes to the shift cable and bolt this in place. Instructions (with photos) are included in the package.
To quote Dick.... "DON'T carry the kit in your glove box, put it ON!! Sitting side of the road or in a parking lot waiting for the tow truck because your shift cable repair kit is in the glove box won't be fun."
Shipping is one cent.




Transmission Shifter Repair Kit


Click To Enlarge





  • Item #: DKTTR-SRK
 
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AppleJack

Active Member
TY - looks like I need to crawl underneath and take a look...

No, but I appreciate the heads up black shadow, this bushing of mine appears to be just fine,

Now I'm wondering if there's a bushing at the shifter end as well? Or could it be the rebuilt trans?
 
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budwich

Well-Known Member
you mention "shifting to drive" as the "symptom".... does the same "reaction" happen when shifting "directly" to any of the other gears instead of "D"? IF not, I would suggest you have an issue with the tranny position / range sensor.
 

budwich

Well-Known Member
Yep.... BUT I am not sure that I would go "gong ho" on the removal just yet... unless you got nothing else to do... :smile:

You didn't answer the question about the "test" that was suggested about the different gearing choices. Further, if you can access the switch with the "stuff" in the place, I would check the wiring to / at the switch to ensure that it is seated well.

Since you indicate that even though the dash isn't indicating the correct gear selection, the vehicle can still move / start. That likely indicates that the internal mechnical connections are OK (ie. shift cabling). The problem likely is associated with electrical. you might want to pull the schematic of the area just in case there is a "simple fix" like a broken ground / battery point that might not even be associated with the switch itself and needs checking first.
 

MRRSM

Lifetime VIP Supporter
Changing out the PNSS (Park Neutral Safety Switch) on the Trailblazers and Envoys is never a trivial job. This is because the Two Electrical Connectors on the PNS are literally "Hot-Glued" into position at the GM Factory. If you get too enthusiastic with trying to "Pinch and Pull" those connectors free from the back of the PNS... the internal Copper Harness Wires can tear and separate inside of their insulation and make matters worse.

You will need a Heat Gun to Heat up those two connectors ...First... and after then after replacing the PNS with an OEM ACDelco, use two Zip-Ties per Connector to ensure that they cannot withdraw from their seats afterwards. At between 4:00 and 6:00 into this video, there is more information on where the Shaft Lever on the 4L60E must be filed down slightly to avoid destroying the New PNS center Collette during Installation.


Also... if you discover that the PRNDL Dashboard LED is malfunctioning... either being very dim or not working at all... It may well be due to a problem with the soldered Dash Panel Connections being poor:

 
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AppleJack

Active Member
Oh - I'll try that too. So range/position sensor is different from PNSS? That's what comes up when Googling 4L60E range/position sensor?
 

MRRSM

Lifetime VIP Supporter
Its semantics... The PNSS (Park Neutral Safety Switch) Part Name and the expression 'Range Sensor' are synonymous with one another. The latter expression is being referenced in this Video that also emphasizes the need to File Down the Shift Position Lever Shaft BEFORE you install a Brand New PNS.

Mind you... I'm NOT advocating the use of an Epoxy Glue to Gerry-Rig a Damaged New PNS... this video just shows the commonality of the different naming conventions for the PNS. What the VOP is contending with is what can happen when somebody else purchases a Brand New PNS... and then after it gets FUBARed because they tried installing it on the Shaft WITHOUT having First Filing it Down. Afterwards, it can get R&R'd and can wind up back at the Parts Sellers and Counter and get Re-Stocked for the next unsuspecting customer. ( Now THAT guy really is acting like a "PNS")

So when you obtain either an ACDelco or Delphi PNS...before you leave the Auto Parts Store... examine that Plastic Internal Rotating Piece very closely for ANY signs of Damage. Note that the weird looking Gray Metal apparatus is strictly installed on the outer body of the PNS in order to keep that center piece in its proper orientation.

That metal device gets removed just prior to double-checking the proper position of the Shaft using the Lever installed temporarily to cycle through the various PRNDL Positions and ensure that the final position is set in the PARK location before removing the Lever Arm and finally installing the PNS.

Once that is accomplished, with the 13MM Bolts loosely installed... there will be a slight adjustment range allowed to move the Body of the PNS slightly up and down while checking that the Transmission Shift Handle inside the cab of the Vehicle is perfectly aligned with the PNS AND the Gear Positional Movements occurring inside of the 4L60E Transmission.

Sometimes... installing that PNS roughly centered within that small allowance for re-positioning the Body of the PNS is all that is required before tightening down those two 13MM PNS Bracket Bolts (...EZ on the Torque Here!) and then re-installing the Harness Connectors, double secured with Zip-Ties and installing that New Plastic Button inside of the Shift Cable and popping it into the outer Shift Lever

 
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AppleJack

Active Member
Thank you sir!

Last two times I drove everything working as designed. Am waiting for next malfunction to try shifting to 3 or 2 to see if problem persists...
 
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AppleJack

Active Member
So earlier I had this: placed shifter in drive, but display indicates N, moved it directly to 3, then 2 and display matched indicating third and second.

Now what? An adjustment of the range sensor? Think I'll pay a visit to the repair shop that rebuilt the trans back in December...
 
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budwich

Well-Known Member
Likely issue is the range sensor... did you check the schematics to see what is associated with the sensor (my memory ain't good).... I think its a simple "resistance bridge"... could be as simple as a dirty contact at the "d" point. Not sure if the sensor itself can be disassembled for cleaning. Either way, you likely have to remove it.

I do believe you can track to thru the schematic and find where the "other end" of the sensor shows up and do some simple measurements at that end (looking back toward the sensor) to determine the differences at "n", "d", etc which will confirm things.

You might even pick up a sensor locally (with a good return policy) and do some bench testing with a meter to understand what's happening during shifting.... just another thought.
 
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AppleJack

Active Member
So, to follow up and resolve this issue: Went back to hydra-tech trans shop and they replaced the range sensor for me. Problem now solved. Less than an hour and $75 including the part from O'Reilly. All good for now...Thanks again
 

budwich

Well-Known Member
ahh ... good. I missed the point about the "recent tranny refurb" install. I assume it was them so it is good that they stood behind the "refurb" and fixed the associated part.
 

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