Transmission starts in second gear - JeepForum.com
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post #1 of 7 Old 08-12-2020, 09:43 AM Thread Starter
hilljacknm
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Transmission starts in second gear

Transmission seems like it starts off in second gear when the selector is set to D . At full throttle, the trans seems to down shift to first. Selecting D or 2 on the shifter feels the same when driving from a stop. Shifting to 1, the trans goes into first gear.


Whats going on here?


Have adjusted the TV cable from one end to the other. With it loose, the trans shifting is more sluggish. Tightened all the way shifts are better, but still starting in second gear.


A little background. Installed a Cascade Transmission master solenoid kit a few months ago. Trans was shifting well after that.


Trans fluid level is good. Added some more, and actually overfilled it a little. Current problem was still there. Drained the fluid down to normal same problem.


Trans shifts are softer now than right after the solenoid kit install.


Adjusted the front band again. No change.


What should I check next?


1996 ZJ 5.2
Doug Thorley Headers, Kolak exhaust
B&M 70268 trans cooler
BFG KM3 30x9.50"
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post #2 of 7 Old 08-12-2020, 10:52 AM
Timo_90xj
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Have you checked the fault codes? If no fault codes are showing, either the electrics are fine or they just aren't throwing a code.
If you are 100% sure you have all the gears when selecting manually, it is likely that this is an electrical issue of some sort.

1998 Grand Cherokee 5.9 LX daily driver, 1.75" BB, 32" KM2s, HPD30 Eaton e-locker/D44a stock LSD, 4.56 gears, custom- fabbed tube bumpers and tube fenders,...


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1990 XJ Limited (4-door), 4.0 I6, AW4, NP242, ***rolled and totalled @ 165k miles***

***Under construction***
1990 XJ (4-door), 4.0 I6, AW4, NP242, PBR 42" tires, Unimog 404 portal axles, 110" WB, full cage + uniframe completely rebuilt, front 3-link + panhard / double triangulated 4-link rear,... ***SOLD***
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post #3 of 7 Old 08-12-2020, 11:02 AM Thread Starter
hilljacknm
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Using Bluedriver, no codes reported.

1996 ZJ 5.2
Doug Thorley Headers, Kolak exhaust
B&M 70268 trans cooler
BFG KM3 30x9.50"
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post #4 of 7 Old 08-12-2020, 01:53 PM Thread Starter
hilljacknm
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Tried an ancient ELM32 scanner. It didn't show any codes either.


Found this in the service manual:


Pressure test


Governor / D range closed throttle



Pressure should respond smoothly to changes in mph
and return to 0-7 kPa (0-1.5 psi) when stopped with
transmission in D, 1, 2. Pressure above 7 kPa (1.5 psi)
at stand still will prevent transmission from
downshifting.


Sounds a lot like the problem I'm having. Don't have a pressure gauge for that.



May be going back in with a new Governer/solenoid.

1996 ZJ 5.2
Doug Thorley Headers, Kolak exhaust
B&M 70268 trans cooler
BFG KM3 30x9.50"
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post #5 of 7 Old 08-13-2020, 12:44 AM
Timo_90xj
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Sorry, I forgot to respond to you. You could do a pressure test, and/ or backprobe voltages from the correct pins on the connector for governor sensor/ solenoid.
ATSG manuals have the voltages, but I'd need to dig a little deeper into those to know how to best test it. No point in replacing sensor or solenoid if they check out ok.

1998 Grand Cherokee 5.9 LX daily driver, 1.75" BB, 32" KM2s, HPD30 Eaton e-locker/D44a stock LSD, 4.56 gears, custom- fabbed tube bumpers and tube fenders,...


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1990 XJ Limited (4-door), 4.0 I6, AW4, NP242, ***rolled and totalled @ 165k miles***

***Under construction***
1990 XJ (4-door), 4.0 I6, AW4, NP242, PBR 42" tires, Unimog 404 portal axles, 110" WB, full cage + uniframe completely rebuilt, front 3-link + panhard / double triangulated 4-link rear,... ***SOLD***
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post #6 of 7 Old 08-14-2020, 08:17 PM Thread Starter
hilljacknm
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Might be a week or two before I can work on it. Depends on my schedule. Ordered a set of Mopar sensors to have on hand.

1996 ZJ 5.2
Doug Thorley Headers, Kolak exhaust
B&M 70268 trans cooler
BFG KM3 30x9.50"
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post #7 of 7 Old 08-21-2020, 08:08 PM Thread Starter
hilljacknm
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Installed the Governor pressure solenoid and sensor. Shifts are back to normal. Guess I got a bum solenoid in the master kit. Hope it lasts more than a few months this time.


When searching for information on this problem, found this on a different website.


https://transmissionrepairhotblog-sc...-solenoid.html


Wednesday, August 15, 2007

Chrysler Dodge 42RE Governor Solenoid Problems.


The Chrysler, Dodge transmission series 42RE, 44RE, 46RE, 47RE (A500-ES) 1993 through 2003 are notorious for failing to start in low gear. The culprit is often the Governor Pressure Solenoid. The normal function of this solenoid is to generate a hydraulic pressure based on the road speed of the vehicle. The pressure should be low around 10 Psi at idle, and increase steadily with road speed, and throttle response to a high of 100 Psi.

As with earlier, hydraulic ( non electronic) transmissions, the governor pressure is used to move the shift spool valves in the transmission. When a valve is shuttled, the transmission fluid will be directed to a different circuit, causing the application and release of clutch elements. In simplifying the system, consider the 1-2 shift valve to have the weakest return spring. The weakest spring will compress first allowing the 1-2 shift to occur before the 2-3 shift, of which, the 2-3 shift valve has a relatively stronger spring. So the higher the Governor Solenoid pressure, the heavier spring it can compress. ( 1-2 valve moves before the 2-3 valve).

So what happens when you do not have first gear, and your Dodge Ram is trying to start off in second gear? Pretty simple huh? Yup, you guessed it, the Governor Solenoid pressure is to high, and has already moved the 1-2 valve into the 2nd gear position.

To understand why this happens, one must look into the design of the Governor solenoid. This solenoid is a proportional solenoid valve, which uses a tiny internal spool valve to allow the solenoid to give an output pressure that varies in proportion to the electrical current fed to the solenoid. The tiny spool is prone to getting plugged with metallic debris, which either causes it to stick, or eventually get worn out in its bore, allowing transmission fluid to leak by. In either case
the solenoid ends up putting out too much pressure, and hence the loss of low gear.

To make matters worse, the designers of this solenoid found a way to dramatically reduce the size and weight of this device as compared to other like products. Instead of using a large heavy copper coil, the designers used a small copper coil and an internal magnet within the Governor Solenoid. The combination of the small coil, and the magnet, produces the same amount of needed magnetic flux energy, as the larger copper coil used in like designed products. This reduced the overall product weight around 80 %, making the Chrysler Engineers very happy. (Lower weight =improved fuel economy). The downside is that magnets attract ferrous particles.
These little bits of steel that wear in the transmission get attracted right to the solenoid and end up plugging the spool valve, and or accelerating the wear of the tiny spool valve. Chrysler engineers even added a protective shroud around the solenoid to help minimize this occurrence.
But it's function is in my opinion, merely cosmetic.

So when you loose you 1-2 shift at somewhere between 60 & 100K miles, this is the most likely cause. Keeping your transmission fluid clean will help postpone the failure, but it will not prevent it. The solenoid is Mopar part number 4617210. It can be serviced fairly easily, but you will have to drop the transmission pan to get to it.
Posted by ScotteeKay at 7:20 PM



Maybe this can help someone.
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1996 ZJ 5.2
Doug Thorley Headers, Kolak exhaust
B&M 70268 trans cooler
BFG KM3 30x9.50"
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