Trans in D position refuses to shift to 1st....

[RamVanMan]

Hi all;

This has me confused. What is going on is that all the sudden, any attempt to keep the trans in D in 'normal' everyday driving, say stop & go city & highway, is difficult.

If I come to a stop, then try to go again, it acts list-less, takeoff is slow, apparently it's trying to start out in 3rd gear (my guess). I'm afraid to do so as it sounds like the engine is laboring & the trans is slipping.

What I'm doing now is to shift down to 2nd with the column shift while stopped, then it appears to start out normally.

Of course, when I reach about 40 mph or so, I've got to shift back up manually to 'D'.

What I'm curious about is if this is more likely a transmission issue or just a shift linkage malfunction. :huh:

Other than this, the trans works normal. No funny slipping, surging or chattering. It kicks down properly, too.

I appreciate any helpful 'bone' anyone can throw me.

FYI the trans has been rebult 1.5 years ago & 20,000 miles ago, and I use ATF +4.

Best regards,

David B. Ram Van Man

[alloro]

What I'm curious about is if this is more likely a transmission issue or just a shift linkage malfunction.

It's possible the linkage is misadjusted and is holding the shift lever on the tranny 1/2 way between Drive and Neutral. First make the attempt to adjust the linkage If that doesn't solve the problem, then it's likely an internal problem.

[B-300]

The symptoms are that of an "re" transmission with a bad governer solenoid or transducer.... The "re" transmission uses these electrical parts inplace of a hydraulic governer.
The "rh" transmission is the hydraulic governer type. It has 2 or 3 wires connecting just above the linkages on the left side of the transmission... The later "re" model has wire wires at this connection.
An "re" type transmission will start in 2nd (limp-home mode) if either part fails... Have it checked for codes. (The "rh" to "re" change occured in vans in about the '96 to '97 model year.)

[RamVanMan]

Thanks to both of you for your suggestions !

B-300, I did find another thread or two, on the Ram truck forums (Durango ?), anyhow, that suggested, as you did, that the governor pressure sensor & transducer are at fault.

Our local NAPA parts man checked with a Dodge dealer head mechanic and they said that if I pulled the pan, checked to make sure no large metal particles were floating around, that if I changed out those two parts, all should be well.

(Someone else said maybe a 'vehicle speed sensor', too.)

I don't suppose anyone has any links to a diagram or procedure that shows how to change those parts out ?

Somewhere I have a Haynes manual for this van, maybe it will show this operation.

I sure appreciate the suggestions. I will report back what transpires with this repair.

Regards,

David B.

[RamVanMan]

The symptoms are that of an "re" transmission with a bad governer solenoid or transducer.... The "re" transmission uses these electrical parts inplace of a hydraulic governer...........
An "re" type transmission will start in 2nd (limp-home mode) if either part fails... Have it checked for codes. (The "rh" to "re" change occured in vans in about the '96 to '97 model year.)

Thanks in part to your helpful info, the problem is solved. I Appreciate your insight.

I also found a guy on the turbodiesel forums at TDR who had posted pics with a pretty detailed description of how he replaced the bad governor pressure solenoid & sensor.

His trans is probably a 47 or 48 RE, but I understand they're identical in most respects to our 46 RE's, 1996 and later. Here:

http://www.turbodieselregister.com/forums/24-valve-engine-transmission-1998-5-2002/112839-governor-pressure-solenoid-sensor.html

The result ? Perfect shifting, problem gone ! No more 'high gear (2nd or 3rd) starts'. Now when in 'D', whether from a momentary stop or from the park position, it starts out in 1st, gently shifting upwards. Throttle mid to high, it holds the shift longer.

My only mod on the procedure, was that I had to take off the governor body itself, to gain access to the spring clip that held in the gov pressure sensor. There are 3 - 11 mm bolts & 2 torx head smaller ones that hold on the 'governor pressure solenoid retention bracket', plus one more 11 mm bolt and the whole aluminum subpart (governor body) drops off in your hand. (no funny or loose parts - never fear.)

Look at the topside, the retention clip is fitted into the groove on the nipple of the gov pressure sensor. Carefully remove with needle nose pliers - use light pressure, if you crush it you'll have to bend it back when reinstalling it exactly that way when inserting the new sensor.

Parts were a bit cheaper at NAPA than at the Dodge Dealer. I paid about $ 78 each. I later discovered that www.Transmissionpartsusa.com had 'em a bit cheaper.

In any case, this common 46 RE transmission problem was not that hard to fix. And my tranny pan was clean - no broken parts or clutch face residue so that was the only problem.

I refiltered & reused the 2 month old ATF +4 Valvoline / Mopar spec fluid. No point in tossing it out @ $ 5 per quart.

Regards, David B.

[RamVanMan]

After driving a few hundred more miles, a report: I am amazed at the 'performance increase' this repair has effected. WAY smoother shifts, way more responsiveness to my pedal inputs, and holds the gear (doesn't kickdown overly easy now) on gradual hills. This should help the trans last longer & maybe increase mileage, by keeping over-revving to a minimum.

I don't just mean better performance compared to it when it failed to downshift while stopped, I mean compared to any time earlier in the last 1.5 years since a rebuild.

Could it be that the use by the rebuild shop of Dexron Mercon fluid (which they swore up & down would be 'just fine we use it all the time in Chrysler trans rebuilds !) contributed to the relatively short life & failure of the Gov pressure solenoid & sensor ?

I will, henceforth, run nothing but ATF +4 in our Ram Van Transmission !

David

[leeann]

Could it be that the use by the rebuild shop of Dexron Mercon fluid (which they swore up & down would be 'just fine we use it all the time in Chrysler trans rebuilds !) contributed to the relatively short life & failure of the Gov pressure solenoid & sensor ?


They can swear up and down all they want: Dexron/Mercron is only to be used to top up a Chrysler tranny.

The PO of my van had the tranny flushed (without a filter replacement) and the shop put Dexron/Mercron in - and it ruined the tranny within 2000 miles.