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42RH transmission problem

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Old 06-12-2018, 08:01 PM
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Default 42RH transmission problem

Hi All,
I have a 94 dakota, 3.9L V6, RWD, daily driver. The automatic transmission is a 42RH per the dodge shop manual and is stock and was rebuilt several years ago. I noticed yesterday a sudden change in that the shifting pattern has changed to a spongy or sluggish action. Its not as crisp as it was before. The engine is not revving higher than normal but I have to step on the gas more now on hills. Most notably, going up hills i normally travel on, I had to floor it to keep a decent speed, the engine was NOT revving, and its coolant got warmer than normal until i got back on level driving and in cooled back down. Even though I had the shifter in Low gear, it felt like it was not in Low and the engine was straining. In neutral the engine revs good.

Fluid is ATF+4, and is clean/red and at the correct level while in neutral on flat grade.

Any thoughts?
Thanks
 
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Old 06-12-2018, 08:49 PM
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I forgot to mention that the speedo died recently...just sits at 0 while driving. The transmission wiring and plug look intact but I have not removed the sensor yet,
 
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Old 06-13-2018, 12:18 PM
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If it is a 42RH, the speedo is a mechanical cable on the tail shaft. It has probably broke.

Have you adjusted the front bands? Usually that's the first thing to do on sloppy shifts, although its more prevalent in the 1-2 shift, but will still cause an RPM surge in the 2-3 shift.
 

Last edited by robertmee; 06-13-2018 at 12:20 PM.
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Old 06-13-2018, 12:48 PM
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Speedo sensor on the tail is electric, 3-wire.
I have not adjusted the bands yet. I plan to drop the pan to adjust both bands, check the filter, and check for broken parts, grindings, other clues. I also checked the throttle cable. Its set correctly and looks fine on both ends per the factory manual.
 
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Old 06-25-2018, 03:58 PM
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Since the last post, I replaced the 3-wire speedo sensor with a new one. The plastic drive gear was fine. However the speedo gauge is still not working correctly. The highest it goes is 10-15mph. However the Odometer& trip meter are both working fine (seems the old speedo sensor was fine and the speedo gauge is what's acting up) The odometer and trip are measuring spot on.
This weekend I dropped the trans bottom pan. Changed the filter and fluid and adjusted the front and rear bands per the dodge factory manual specs but they didn't seem far off to begin with. After that and refill, test run, the first (low) gear still seems sluggish or maybe slipping a bit. The engine is not over rev'ing like its slipping free but its not how it should be. 2nd and 3rd seem to hold good. Reverse is ok.
In terms of what was in the pan, i found some sludge, some fine metal powdery gunk on the pan magnet and just a few very small aluminum specks in the sludge and on the filter. Fluid was red, not burned. No big broken items found.
Any thoughts? Would the 2 solenoids on the valve body or a dirty or sticking valve body cause this? Also my computer codes are clear, only a "55" comes on as expected.
Thanks
 
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Old 06-25-2018, 04:43 PM
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On the 46R? transmissions, the factory specs tend to leave the bands a bit loose...... our one-time resident trans guru recommended backing the band adjuster off two full turns each, after torquing to 72 inch pounds, then then locking them down. No idea if that would also apply to the rest of that trans family.
 
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Old 06-25-2018, 06:27 PM
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Well I set them 2-1/2 turns for the front and 4 turns on the back after torquing to 72 in-lbs (6ft-lbs) per the 42RH manual.
Some NEW additional info.. on the way home this evening, I drove up a steep hill road then level then downhill (back of the mountain). On the uphill it had the same semi-slip/straining feeling, even with the lever down to 1st/low gear. Then up on the level terrain, when taking off at the stop sign in Drive, it had a delayed and harsh engagement, a new development. Engine would increase in rpms higher than normal and then grab on. At cruising speed, it seems firmer. Finally on the way down the hill, I put it in Low (going at a very slow speed) and trans didnt feel to go into low gear (the tach sat about 1000 or so, when it should have increased to 1500 or so. I gave it some rev, and then it dropped to low gear and took up the load, again like a delayed engagement. When I eased on the gas, the tach stayed up higher as it normally should in low gear.
My preferred trans mech is out of town for a while, so I am hesistant to take it elsewhere but am concerned it may give out altogether on the roadway,, ie wrecker service.
Any thoughts would be appreciated.
 
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Old 06-25-2018, 06:55 PM
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Wow, that's MUCH different than what I am used to....... Given that's a hydraulic trans....... beyond my knowledge.
 
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Old 06-26-2018, 01:12 PM
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Almost sounds like pump pressure to me. Might be worth it to park it, till your guy gets back.
 
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Old 07-01-2018, 10:13 PM
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Originally Posted by robertmee
If it is a 42RH, the speedo is a mechanical cable on the tail shaft. It has probably broke.

Have you adjusted the front bands? Usually that's the first thing to do on sloppy shifts, although its more prevalent in the 1-2 shift, but will still cause an RPM surge in the 2-3 shift.
nope. 94 was the 1st year that they did away with the cable there is a speed sensor in the same location though. 93 and older has the speed sensor that also had the drive for the speedo... if you pay attention the font on the odometer numbers is different between cable drive and electronic speedo's... I have had 92, 93, 94 and 96 Dakotas along with an 89 and a 90.
 


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