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Discussion Starter · #1 ·
NOTE: 46rh was rebuilt (by me), with new default stall lockup torque convertor, about 2000 miles ago. Up until a month ago, the 3-4 shift was working fine.

So, I just started having an issue where my overdrive unit engages and then disengages periodically just after the 3-4 shift while accelerating and giving light throttle. It'll drop back into 3rd, shift up into 4th, about every second or so. The only ways to stop this are to:

1. Disable overdrive at the overdrive disable switch on the dash
2. Apply more throttle to keep it kicked down into 3rd
3. Apply less throttle to keep it from kicking down into 3rd and stay in 4th.

I've adjusted the throttle valve cable, and the 1-2, and 2-3 shifts happen just the way I like them.

I've changed the trans fluid, using ATF-4, and a new filter.

I've checked the throttle position sensor (TPS) by looking at this thread (http://ramchargercentral.com/vehicle-help/!988-w250-tps-sensor/msg3462536/#msg3462536). As I mentioned on that thread, there does not appear to be any way for me to get the TPS to read over about .65v at idle. However, the install instructions on the new TPS I installed says that .6v at idle is normal, and about 3.6 at WOT is expected. That's what I found in my measurements.

So, I'm unsure how to proceed.

I've heard the only other thing to check is the transmission speed sensor. That might make sense except for the fact that my speedo is working correctly/reliably/consistently. Is there any way that speed sensor (FSM calls it a 'distance sensor' I think) could be faulty enough to cause issues in the 3-4 shift but still give me a stable speedo reading?

Mitch
 

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Discussion Starter · #2 ·
Two more things to note:

- over about 50mph or so, overdrive stays locked in and works just fine (e.g. highway driving is fine. Hills suck right now)

- I think the 'hunting' between 3rd and 4th started after I got work done on my rig for the 4in lift I did. New exhaust routes right behind the tcase, and the exhaust guy moved the vac bottle and lines out of the way to make room for the driver's pipe to route to the left of the trans before it curves behind the tcase and Y's into the driver's pipe to form a single 3 in pipe for cat and muffler and tailpipe. I'm wondering if maybe stuff got jiggled around or damaged during that process that is now causing the 'hunting' issue. The lead from the speed sensor on the overdrive unit *was* a pulled a little tight by a zip-tie the exhaust guy added when he put everything back together.

Mitch
 

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96 is an RE not RH , 92 has no gov pressure electric switch yet, just the mechanical fly weight . I'd say that your pressure has dropped some , or the aluminum governor housing is bad , it does not take much to effect the change you report , take a pressure test ? back off on the throttle pressure "slightly " ? and try that ? look and read at this web site https://transmissioncenter.net/product-category/dodge/
 

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Discussion Starter · #5 ·
So, I was wondering what actually energizes the overdrive solenoid, and found this post on another site:

https://www.nagca.com/forum/showpost.php?s=5e6faf7eea0ef20253752c79f2eee097&p=322403&postcount=3

I guess if the fluid pressure isn't high enough coming out of the 2-3 shift valve you might get some sinusoidal oscillation of the 3-4 shift valve/etc. that could account for the behavior I'm seeing.

dodge82273, when you say 'back off' on throttle pressure, do you mean move the fitting on the throttle valve cable 'forward' more (increasing shift RPM and shift firmness)?

Is there another way to increase line pressure?

Mitch
 

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there is a 3 wire vertical plug that runs to the solenoids , I'm sure you know , the center wire is HOT when ever the key is ON , the 2 other wires are 1 ground for each solenoid , those are controlled factory , by the pcm , it decides to supply ground or NOT completing the eletro magnets circuts . the pcm looks for a minimum engine temp , and reportedly, road speed . All the solenoids do is allow available oil pressure to pass or not . all the dash switch is is an OFF button / and pilot light  . The front pump pressure runs thru the flyweight governor  on the tail shaft , its amount of movement controlls the oil flow/pressure it should be all out at 42 mph , from there its whatever pressure your pump and seals are putting out . the pressure required is aproximatly 1 pound per mile per hour , 42 psi required for shift at 42 mph . I can't say which direction to move cable off hand , but move it in the direction so the trans thinks you are NOT stepping ON the throttle so hard , I.E. back off throttle pressure ..

look at the ptc web site , read the how to's / why's listed here and there with the parts listings ,  all the info is there free and accurate .( Time well spent)  your 46rH can also be set up to shift automatically but, when you want it to, at the speed you want, using 2 pressure switches and a vacume throttle switch  . by changing the switch's open/close pressure , you change the speed at which it shifts . some folks prefer toggle switches .. but the oil pressure from the governor has to be there first . there are different weight governors for diesel and gas , less rpm/ more rpm .... and yes there are pressure adjustments , that can be made , but why they would change? see pic 
 

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and even the fsm is NOT real clear on that ...... requires tool numberXXXXXX to set depth on the one .... so yeah how / why'd that change ?
 

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Discussion Starter · #9 ·
Ok, I fiddled with the TPV cable setting a good chunk of today. I tried moving the fitting at the throttle-body *rearward* and that made the shifts later/firmer, and for a small distance change (1/8 in maybe) improved the 'hunting' problem by narrowing the band in which it would hunt between overdrive on/off. If I went much past that, things degenerated with really high shift RPM, etc.

So, I tried moving the TPV cable fitting *forward* by a bit. It made the shifts earlier/softer, and generally made the hunting problem worse. So, I've decided to go rearward 1/8 in on the fitting, past my original TPV fitting location (marked it with a sharpie beforehand thankfully). :)

I may just have to try the custom '2 pressure switches and a vacume throttle switch' approach (I read the page on that and it does seem pretty interesting).

After thinking through my rebuild a bit it just dawned on me that I put a trans-go TFOD-Jr shift kit in my 46rh as I was rebuilding it. I had completely forgotten (it was a couple of years ago now). Since the rebuild it has been a little bit finicky keeping overdrive locked in just after the shift into 3rd (e.g. 45-50). But, no, it never hunted they way is has been for the last month (something has changed, just don't know what).

That trans-go kit had you drill some holes (one/two in the valve body, and a few in the divider plate between the upper and lower valve body sections, at a very specific location given by a detailed picture). I chose options to get 'slightly firmer' lockup. It had more aggressive options, and I picked the mildest increase in lockup (to help with towing). Not sure if I've muddied the waters so badly now there is no way to diagnose the problem. I'm sorta regretting that choice now. :-(
 

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I've done the shift kit deals and they did what was advertised , yes the "change" is what I'd wonder about , they all will be going up/down  when your right at that shift speed ,( say 42 to 50 mph ) its hard for them to decide because its a combo of the foot pressure and the ... oil pressure when ever your at the shift point or near that speed .    I found simple pressure switches on in different pressures , and an adjustable one , ( with-in a "range" ) on line from a industrial supply house .... as well , so it could be completely automatic , and adjustable ...
 

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I'll offer another solution - put the OD on a toggle switch and activate/deactivate it 'manually'.  I went through the same situation you're are in now and IMPO once the OD system wiring and sensors degenerate badly enough to give you these problems there is very little chance of restoring the original system(s) to get it all back.  If you want the overdrive to engage 'now' - regardless of how hard you are pushing on the go pedal, then separate the OD wiring from the factory wiring completely and wire up the OD to a toggle on the steering column shifter. 

My truck was a Cummins and I considered the boost level during OD engagement - with the toggle switch, when manually engaging OD regardless of where my right foot is and regardless of the boost level the OD will engage - with the toggle switch it will have no choice, which also means it was up to me to monitor how much boost is being generated when I engaged OD.  I never engaged OD unless I was at/under 10 lbs of boost simply to try to prolong the life of the OD clutches - 10 lbs of boost (or less) just 'felt' like a good baseline pressure to engage OD...but if I really needed to boogie I'd leave my foot in it and engage it whenever I needed the next gear and man the truck would flat out go - no 'hunting' at all - none - with the toggle switch method there is no possibility of hunting - it's either in or out.  In your case tho, with the gasser there isn't really much to worry about - just engage it when you want the gear.

Granted the toggle switch method is no longer 'automagic', but it is for sure a guaranteed to do the j.o.b.  Personally once I got used to it I MUCH preferred engaging the OD manually.  Naturally sometimes I've forget to disengage it when coming to a stop, and that just meant OD would hit right after 3rd...which you notice right away because the truck sort of bogs down a bit - no matter - just lift a bit, disengage OD, accelerate through 3rd, and re-engage - it worked great {cool}.

- Sam
 

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Discussion Starter · #12 ·
Great discussion and advice here guys. I'm gonna noodle a bit on whether I want to go manual or auto for OD. I had the habit of yanking out my automatic chokes in my old carb-induction days in favor of a manual choke, so the manual OD doesn't seem too far off of that. That said, I'm much older and bit lazier (OK a lot older and a lot lazier) now, so automatic might be more suitable. It's great to have the info for picking either path.

Thanks!

Mitch
 

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Discussion Starter · #13 ·
After some consideration, the wife will be driving the truck from time to time, and she will *not* be happy with a manual OD switch. :)

I'm looking at trying the pressure switch mod, and starting with this kit:

https://transmissioncenter.net/shop/patc-727-to-518-46rh-conversion-kit-click-here-for-727-to-46rh-swap-wiring-diagram/

and going with the adjustable pressure switches (since I'm thinking of going with 35s, but still running 32s, I'm not sure what shift point will work the best yet).

Does anyone know what size/thread the governor pressure port is on a 46rh? 1/8 npt maybe?

Mitch
 

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pretty sure your right 1/8 npt , but I'll look at on today just to be sure its NOT 1/4 npt , I do not think it is ...
 
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