Transmission clunk on hard acceleration
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Joined: Oct 2017
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From: Tilton, NH
Transmission clunk on hard acceleration
Hi everyone, I have a 2004 Dakota with a 3.7 and 42rle. When I first got it a few months ago it had a problem where if I accelerated hard, especially from a slow roll it felt like something was binding up. Feels like right under me in the tranny. Slight grinding noise, the engine would rev but then something bound up and I'd have to let off and then take off more slowly.
So first thing I checked was ujoints and they were both shot so I replaced both. The problem went away so I thought it was fixed, until yesterday it did it again. The person in front of me was turning, very slowly so after they turned I got into the gas and the truck stumbled. Something bound up and a slight clunk from the tranny. I let off the gas and was easier and proceeded fine. Shifts fine, no vibrations. But if I get into the throttle from a stop or slow roll only, it clunk and stumbles. Any help is greatly appreciated. Thanks!
So first thing I checked was ujoints and they were both shot so I replaced both. The problem went away so I thought it was fixed, until yesterday it did it again. The person in front of me was turning, very slowly so after they turned I got into the gas and the truck stumbled. Something bound up and a slight clunk from the tranny. I let off the gas and was easier and proceeded fine. Shifts fine, no vibrations. But if I get into the throttle from a stop or slow roll only, it clunk and stumbles. Any help is greatly appreciated. Thanks!
Legend
Joined: Feb 2005
Posts: 8,058
Likes: 183
From: Fort Worth, TX
I don't know much on the 42RLE / Ultradrive / A606 family of transmissions. I'm actually googling it right now.
Apparently it does not have bands at all, everything is clutch based
It is a 42LE longtiudinal transaxle that has the rear section fitted with an output yoke rather than a feedback chain.It sounds like a simple transmission service may go a long way in resolving your issue, worst case the valvebody may need to be dropped/opened and see if there is a check ball or spring hanging somewhere. I don't think that would require a total rebuild.
https://www.allpar.com/mopar/transmissions/42LE.html
Originally Posted by ALLPAR
Inside the 42LE are five hydraulically applied clutches. Four of the clutches are released with conical belleville springs [a spring shaped like a cone/concave washer) while the other is released with a coil spring. Three are input clutches, giving input power to the planetary geartrain; the other two are holding clutches and hold planetary geartrain components.
Within the 2-4 and low/reverse clutch assemblies, and behind the input clutch assembly, is the planetary geartrain. Inside, there is the front sun gear (in the center of the front carrier and welded to the center of two hubs); the front carrier assembly and rear annulus, which are splined together to be one unit; the rearsun gear (in the center of the rear carrier assembly); and the rear carrier assembly, which includes the rear planetary carrier, front annulus gear, and output shaft as one unit. The rear carrier assembly also has no clutches connected to it as is where all output power passes through.
- The underdrive clutch is in front of the input clutch retainer.
- The overdrive clutch is the center clutch in the clutch assembly.
- The reverse clutch is in the back of the input clutch assembly and uses the same piston, pressure plate, and belleville spring as the overdrive clutch.
- The 2-4 clutch is behind the input clutch assembly.
- The low/reverse clutch is in the back of the transaxle case behind the 2-4 clutch.
Within the 2-4 and low/reverse clutch assemblies, and behind the input clutch assembly, is the planetary geartrain. Inside, there is the front sun gear (in the center of the front carrier and welded to the center of two hubs); the front carrier assembly and rear annulus, which are splined together to be one unit; the rearsun gear (in the center of the rear carrier assembly); and the rear carrier assembly, which includes the rear planetary carrier, front annulus gear, and output shaft as one unit. The rear carrier assembly also has no clutches connected to it as is where all output power passes through.
Last edited by magnethead; Jan 10, 2018 at 07:45 PM.
