Jeep Enthusiast Forums banner

46RE Transmission Hydraulic Noise?!?!?

11K views 16 replies 3 participants last post by  jlipka98zj 
#1 ·
Okay guys, back for more help. Thought I fixed my last problem, new problem popped up. Background: 5.9 Limited (46RE tranny). Recently rebuilt, custom valve body from APS, lots of goodies, etc, etc. I was dealing with an issue where it wasn't shifting until 3000 rpm, a new Mopar TV cable fixed that.

The other day I was enjoying my Jeep again running errands, and I noticed a very weird sound. Whenever the tranny is in any range OTHER THAN park, it makes a hydraulic noise. Best I can describe it is the moaning sound an old ford steering pump used to make when it was getting old and you turned the wheel. In fact, at first, I actually thought my power steering pump was going out. Popping the hood proved I was wrong. This sound is RPM dependent, doesn't seem to sound any louder or quiter in any particular range than another. As mentioned, it doesn't make this noise in park, but it does make it in neutral. It sounds like it is coming from the bellhousing area.

Another interesting twist. The sound is RPM-dependent, meaning it gets louder with engine RPM. However, about a half-second before the tranny shifts, the sound goes away. It comes right back after the shift is completed, and will go away immediately preceding the next shift. And during the 2-3 shift, it feels like the tranny is momentarily letting go.

Lastly, it sounds like there is a mild mechanical sound (scraping and banging) noise in the mix, too.

Now, my research has yielded a couple possibilities, which I will list here:

  1. Torque Converter - Heard this as one of the most frquently cited reasons for sound coming from the bellhousing area. However, most things I've read say that this sound disappears in Park AND Neutral. I did a stall test and RPM was normal (about 2500 - it's an APS converter, nominal 2500 stall).
  2. Flex Plate - Heard these can crack or the bolts can be loose. In all my years of wrenching I've never seen it but okay. That would certainly explain the mechanical sound but I don't think it explains the hydraulic sound. Also, wouldn't it be making noise in park if this were the culprit? Easy enough to check, just pull the inspection cover.
  3. Plugged Filter - I've heard this noise can be caused by insufficient fluid flow, caused by a plugged filter. I fear this one not because changing the filter is difficult or expensive, but because that means my new tranny is generating enough debris to plug a filter = no bueno.
  4. Cooling System Restriction - similar to the filter problem above. Heard this can be a problem. I figured a somewhat easy test would be to take like a two-foot piece of tranny hose and "short-circuit" the cooler ports. Take the inlet and tie it to the outlet. If the sound goes away, hope a flush will clear it. If not, new radiator time.
  5. Valve Body Problem - I've heard a buzzing valve inside the VB can cause this sound. The fact my sound goes away right before shifting somewhat supports this. My VB has the no-buzz PR valve and TV and all the other fancy valves known to buzz. However, I've heard crap can get into one of the valves and cause it to buzz. The VB was assembled by Wayne at APS. Again, my concern here would be how the crap got in the valve in the first place.
  6. Internal Damage - God, I hope not. I just don't know what would be making noise in N but not in P. However, internal damage might pollute the tranny with debris, possibly contributing to 3) or 4) above.

Can anybody help? Any ideas? I'm sick of dumping money into this transmission!
 
See less See more
#3 ·
I started researching my backup plan, which is to buy a Level 3 Mega Viper transmission from PATC. I'm just tired of dealing with it. ANyways, I've called these guys before and they have never refused to answer a question for me, so I'd figure I'd ask what usually causes a whine. The guy was definitive - torque convertor or pump. I asked about the fact that it still makes noise in neutral and he said you can't count on that anymore. Sometimes they do, sometimes they don't. What I do know is that a 46RE charges the converter in N, but not in P. That said, my shift kit came with a manual valve that is supposed to allow converter charge in P.

The phone call was not without humor. I asked him what the easiest was to diagnose either problem was. His response - "disassemble 'em".

Any comments?
 
#5 ·
My 97 5.2 does the same thing occasionally. A weird HMMMMMMM kinda noise when in gear. When I first bought it, it would do it constantly. Now, it rarely does it.. I have no idea what it is or was. The transmission works fine but it still weirds me out. I know exactly what youre talking about but, unfortunately, cant be much help.. Im interested to see what others say about it though. Good luck man.
 
#6 ·
Ever changed your tranny filter?

The more I research, the more I think that is what is going on with my transmission. If that is not the problem, then it is the pump itself. Either scoring on the pump gears/gear cavity, or a bad bushing.

I've all but ruled out the TC at this point because a bad TC tends to make the most noise when you place it in D or R and hold the wheels stationary with the brakes. At this point, the turbine (hooked to the rest of the drivetrain) is held stationary, while the impeller (hooked to the engine), is moving. Giving a little gas (as in a "stall test"), should exacerbate the problem. In P & N, the turbine and impeller are spinning at the same speed. As you recall, my converter passed a stall test fine without any add'l noise so I can (hopefully) rule that out.

Another test I can run is to pull the TV cable off the throttle linkage and actuate it by hand with the tranny in neutral and engine idling. In doing so, you are modulating throttle pressure which is varying demand on the pump. This should change the pitch of the whining. This helps distinguish whether it is a flow problem (pump or filter) or a mechanical problem (bad bushing).

So, order of business is to do the quick n easy first. Try the TV cable. If it indicates mechanical, pull the transmission inspection cover and check for a cracked drive plate or loose TC bolts. If still nothing, tranny's gotta come out.

If the TV test indicates flow, drop the pan, change the filter/fluid, and flush the cooler circuit (again). Before pulling drain plug, say 5 our fathers and pray plug is clean. Before dropping the pan, say ten hail mary's and pray I don't find anything in bottom. If that doesn't fix it, tranny must drop.

Anyways, we have 6 inches of snow on the ground and the thought of parking my commuter car outside overnight and scraping the windows in the morning so the jeep can be in the garage doesn't appeal to me. However, I have a 4-day weekend coming up and will be able to check some things. I have ANOTHER case of ATF+4 on it's way, and will pick up a filter and pan gasket tomorrow, and might as well get another can of Kooler Kleen.

I'll report back with my findings.
 
#7 ·
I changed filter and fluid when I bought mine. And now that I think back on it, it seems to have quieted after that.. Like I said my noise is really hit or miss, and has been absent recently. You seem to have way more knowledge about transmissions than I do so again, I cant be much help on this one man...

Best of luck brotha let us know what you find out.
 
#8 ·
UPDATE: *Thought I'd take advantage of the "good weather" (got above 30*F today, lol) and thought I'd finally take a run at this. Note, i havent dropped the pan yet, im gonna let it drain over night. Pulled the drain plug and the first thing was not a good sign:


I'd say this is probably more than typical wear and tear, would u agree? *Any chance that crap was in the torque converter?

Here was the 3 gallons of fluid I drained:


I realized that this wasn't a very representative picture so I compared it to new fluid. New on the left and old on the right:


Obviously, a difference can be seen. The fluids smell comparable, not burned. I'm not sure if this would be considered normal degradation in color. I read somewhere that dye is actually added to ATF+4 so it changes color pretty rapidly. Bear in mind, this tranny has less than 1000 miles on it.

Okay, so anybody have any thoughts? *As I said, I'm going to drop the pan tomorrow and have a look at the filter. I'm just not to keen on the idea of filling this back up with another case of fluid if it is just gonna be a waste. You ATF+4 guys know this stuff ain't cheap. If this tranny needs to be rebuilt AGAIN, I think I might lose my mind.
 
#9 ·
Also thought I'd share pictures of my remote filters setup:


You can see the "sandwich-style" magnetic filter between the canister and remote mount. And yes, the wix filter hangs way down. It's a full size ford filter. Actually hangs down just below my skid plate. I will source a shorter filter, but it's fine as is for now because I rarely off-road.

Note, I have the fluid cooler supply line ran to this, then this runs to the radiator/aux cooler. Thus, this catches crap immediately exiting the transmission. *Below is on the return line to catch anything existing in the cooler circuit. I back flushed the cooler circuit before doing all this, btw.

 
#10 ·
Seeing the amount of material on your drain plug I suspect your extra filters might be clogged. That could slow the flow and cause the noise you hear.

What is your thinking on those aux filters? A properly maintained trans will go 200k +. Why add a filter, let alone 2?
 
#11 ·
Sorry I didn't explain that very well. I just added the extra filters JUST NOW, while I am letting the fluid drain. They were not there before. My reasoning for adding them is because after the first rebuild with a new TQ, I set the endplay too tight and I promptly ruined a stator support within about 10 miles. This created a lot of garbage in the transmission. So out the tranny came for another rebuild. I cleaned everything, new stator support, new valve body, etc. However, I was having a hard time stomaching dropping $450 on a new TQ to replace one that had 10 miles on it. Maybe a bad mistake.

So anyways, my thought process is that I hope that all this metal shavings came from what was in the old TQ. This plugged off the internal filter and is causing the noise. By adding the external filters, I can continue to filter out this garbage without having to drain/refill 3 gallons of fluid at over $5/qt (I have a mag-hytec pan).

I understand that the mere presence of metal particles is not a good sign. Sure, replacing a clogged filter is easy, but what caused the filter to plug in the first place? I am very frightened to drop the pan tonight. The thought of dropping this tranny out for a 3rd rebuild brings vomit to my mouth. And worse, I checked every clearance and this thing was solid. I have not a clue in the world what went wrong.
 
#12 ·
I know what you mean, it can be extremely frustrating on so many levels. If money is the main stress maker, consider popping in a used 100 dollar trans until you get the good one checked out by a real pro. I dunno, just thinking.

I bought a used engine, trans and transfer case for mine so I would have something in reserve if needed. Takes a bunch of the stress away. I suppose you also need the rig to be dependable....mine is getting there.:rolleyes:

I used to live in Lander. Wyoming is a favorite.

Drop that pan and put in a fresh filter. Check you band adjustments, put her back together and see how it goes....I'm no mechanic but that is what I would do first. You asked what caused the filter to plug in the first place...bands IMO. Its band material. What else could it be?

I have gone through a bunch of +4 getting mine cleaned out. It's ugly expensive.
 
#13 ·
I know what you mean, it can be extremely frustrating on so many levels. If money is the main stress maker, consider popping in a used 100 dollar trans until you get the good one checked out by a real pro. I dunno, just thinking.

I bought a used engine, trans and transfer case for mine so I would have something in reserve if needed. Takes a bunch of the stress away. I suppose you also need the rig to be dependable....mine is getting there.:rolleyes:

I used to live in Lander. Wyoming is a favorite.

Drop that pan and put in a fresh filter. Check you band adjustments, put her back together and see how it goes....I'm no mechanic but that is what I would do first. You asked what caused the filter to plug in the first place...bands IMO. Its band material. What else could it be?

I have gone through a bunch of +4 getting mine cleaned out. It's ugly expensive.
Filter/bands willbe tonight. I quadruple-checked the band adjustment when I rebuilt the trans. But whatever. I'm past thinking I have the answers. I dunno whatever material might be in there. Bushings? Whatever. We'll see tonight.

Im not hard up for the vehicle, I have two others. It's just frustrating because the tranny went out and I spent big money fixing it. Now it may be busted again. So frustrating. Plus the constant mess.

The other thing is I don't have a heated garage so with the temperatures as low as they are, I am basically relegated to waiting until it warms up if I need to go as far as pulling the tranny to fix it.

A guy on another forum suggested that when I had the valve body wrong, it may have been forcibly trying to engage two gears at once, thus burning a band. I'll double check those. God I hope I didn't screw this slushbox!

I'll report my findings, possibly with photos.
 
#15 ·
Update: pulled the pan. Nothing serious in there. Here's the pan as pulled out from underneath the vehicle:


You can see some metal filings but thankfully no major pieces of transmission. Here's after draining the residual fluid. And yes, my ADD got the best of me:


You can see the metal shavings better here. Here's after cleaning before I reinstalled the pan:


Ignore the black marks, I think it is overspray from the factory. Been there since the days bought it. So here was the filter as removed:


Compare this to the new filter:


The result? 15 qts of ATF+4 later, tranny is silent. Test drive indicates function is normal. Adjusted bands when inside. Didn't seem to be much of an adjustment. For now, I will consider this issue dormant because I don't dare say solved. It's doubtful all that metal came from the old TQ isnt it? Any comments at this point would still be greatly appreciated!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top