Transmission Woes 3.9:/NV3500
 

Hello Fellow Dakotians!

So I have an ongoing manual transmission saga on my much loved 2000 Dakota Quad Cab (3.9L, NV3500, 195K miles). The issue is that I think the syncros are shot, but I'm not sure if we killed them, or something else killed them, and am in need of some solid advice.

Behavior:

When the truck is cold, it's difficult to put into 1st, 2nd, or Reverse. The usual tricks help getting things moving smoothly. Touching into a higher gear, going 5th, directly into reverse will engage reverse at a stop with no issue. However after about 5-10 miles of modest driving it becomes almost impossible to shift into 1st or 2nd even with rev matching, rolling, etc. Also, when it gets into this state, the transmission wants to creep in 1st gear (when you get it in). So as it warms up it goes from very drivable to almost impossible to drive, and then it starts creeping when you can get it in gear. Additionally I noticed a bearing squeak/squeal that will go away if you press the clutch in until the throwout bearing puts pressure on the pressure plate fingers. After warning up, if you attempt to put into first the tranny tries to creep, but if brake is applied, it'll sit steady and not stall the motor. (See video for the sound of what I think is the throwout bearing noise and then it going away after pressing in the clutch).

Right after the engine, clutch, and fluid work the truck drove, shifted, and behaved fantastically. Then my son was driving it and it started refusing to go into gear. He was able to limp it home barely. Because of the behavior, we knew the master/slave were not happy given the engagement. I replaced with the pre-filled system and did the fluid swap with the Mopar fluid mentioned below. Then the cycle above started. Cold, driveable, no grinding, a little tough to get into 1st or 2nd, or reverse...but then once warm, no 1st, no 2nd, no Reverse and creeping in gear, but clutch pedal all the way in.

Work Done:

• Full, brand new clutch package. Pilot bearing, pressure plate, throwout bearing, friction disk. This was done less than 2 weeks ago during a motor swap (the old 195K 3.9 developed a horrendous knock).
• Fluid completely changed at time of swap with Pennzoil syncromesh fluid. Small amount of metal on the magnet, and given the miles, nothing more than expected)
• New master/slave pre-filled setup.
• Apart from the throwout noise when warmed up, the tranny is quiet as a church mouse, smooth, no noises, etc.

Thoughts

• I think the syncros are shot. Whether that was a result of my son's adventure and jamming it in gear, or just age, not sure...
• I am worried the pilot bearing is also bad (even though new) that's the only reason I can think of for the creeping even with the clutch all the way in.
• I am willing to throw a rebuilt tranny in it, we love the truck, but I am worried if there is another issue, we'll just kill that one too.
• The clutch aseembly/etc. is brand new, so I think when I pull it, I make them replace it (Autozone Duralast brand)

Would love to hear some thoughts from the pros here. I've read all the threads here, but there is so much going on, I haven't been able to make heads or tails of what precicely is the issue, or if it's all the issues all at once...maybe even a cascading failure situation that wiped out the rest of the world to die as well (pilot/throwout).

Thanks in advance!

Dakota Dunn

I don't think first or reverse are synchronized in any event...... 2nd most certainly should be though. It almost sounds like pressure in the clutch hydraulics is bleeding off, and gets worse as the engine warms.... not allow the clutch to completely disengage. Either that, or contaminants on the flywheel, that get sticky with heat. The squeak until you step lightly on the clutch is likely the throwout bearing.... putting a little pressure on it quiets it down....

I understand all that stuff is new...... Did you resurface the flywheel when the clutch job was done??

Thanks for the input and reply.

If I put the truck in 3rd gear at a standstill it doesn't try and creep, it seems like just enough to start the truck thinking of it, but in third maybe it's not enough to move it, or it overcomes whatever is driving it without stalling the truck?

No, I didn't resurface, just cleaned really well and looked for cracks/glazing/etc. so it was clean.

I do think your thought may have some merit. When I installed the new slave unit I had to route the hydraulics through the steering knuckle and not the usual path that has it a little closer to the exhaust than it would normally be...clutch seems to engage/disengage (like I said in 3rd gear which is still accessable), but maybe there is enough residual heat coming off to make it just enough out of spec to cause the difficulties?

Wonder if I wrapped it with exhaust tape if it'd help or crafted up a heat sheild for it. There was absolutely zero possibility of routing the original path without disconnecting the slave from the master, which is a big no-no in an unbleedable system.

That's gonna be fun.... I don't know what temp the fluid boils at..... but, if it was getting that hot, I would expect to see some evidence of that on the line itself...... If the slave is external to the trans, and you can actually see the plunger, get things good and toasty warm, so the problem actually presents itself, turn the truck off, and crawl under there and see what the slave is doing, when someone else pushes the pedal to the floor, and holds it there. See if it slowly lets the clutch out again... or, if it isn't actually pushing out as far as it should.

Ha! You make it sound so fun, I might just do that for sport! I did during the troubleshooting process put my inspection camera up in the bell housing (not running) to see if the fork was engaging the bearing into the fingers properly. The slave is on the transmission externally, and that's no closer to the exhaust than factory, but the line does follow the new route that follows the exhaust along the frame where before it was outside the frame, and then cut over only being exposed in a small part.

Sadly even with the inspection cover off you can't see any of the "guts", you can only see the flywheel and a small portion of the pressure plate. Without the inspection camera I couldn't see squat internally. Bought some header wrap off ye 'ol Amazon that'll be here Thursday and will wrap it along with the inspection of the system again.

I'll get an update after all that fun.

Thanks again for the extra brain cells...I've barely got two left to rub together after all this fun!

Keep in mind it will take more torque to creep in a higher gear. So 1 and 2 may have enough reduction for the clutch dragging to pull through the gears/brakes. 3 may not have enough reduction, so the clutch just drags with no movement.

I wonder if the slave master assembly is defective or wrong unit or a crappy China part?

What brand did you install?

Maybe a wrong throughout bearing or defective?

That is what I am thinkin'......

Pulled the transmission yesterday, and the throw out bearing was completely toast from a bearing perspective. It was all chewed up and loose. So it was definitely made from Chineseium. I took the whole thing back to Autozone and got a full refund.

I also noticed that the fingers on the pressure plate weren’t returning to their full position. About a 1/3 of them were all the way down. I’m not sure that’s expected or not.

So it goes without saying I won’t be buying another cheap Clutch kit. Thinking of the Sachs on Rock Auto. Anyone have any different recommendations?

on the MC/Slave I could see them working with my inspection cameras and they seem to have plenty of travel/force. But they too are likely Chineseium but so far seem to be working okay...and in the order of operations on the failure, I was having the issues above before the MC/Slave replacement, so I’m thinking the crappy clutch may still be the issue?

I installed a LUK clutch kit in my AX15 trans only part I didnt like was the throughout bearing it was half plastic and stamped steel I purchased a better throughout bearing like the oem part no problems one year.

https://cimg4.ibsrv.net/gimg/dodgefo...01d6e21aea.jpg