I am getting this 2000 ram 3/4 4x4 back on the road. I bought it, put about 100 miles on it, then it sat for 2 years (mainly bodywork/mechanical issue to pass state safety check). I just started it for the first time last week. Kicked over immediately, and runs good. I let it warm up, then I moved it through the gears, positive and immediate engagement. Couple days passed, I decided to drive it short distances to work out any kinks. Trans shifts great, no problems. Shifts into/out of 4x4 fine. I stopped off in neutral, and I hear noise, like a whine - not a good sound at all. Dang it... I do some more testing, it seems to only occur in neutral. There is a light noise I hear in park, but its not the same and might be something other than the trans.

I've done some web searches, didn't find a similar condition.

What goes on in neutral that doesn't in other positions?

Related info:
The PO had changed the trans fluid the year I bought it, so the fluid looks good on the dipstick.
The oil level is just a little under the add mark, but I checked it when it was still cool (not hot). But I'll add some more fluid tomorrow to bring it up into range when still cold.
The check valve is still present in the trans line, and its using the stock in radiator cooler.

 

How loud is it? Does the noise go away immediately in gear?

 

Yes, moving from N to D, immediately engages and noise it gone. Noise is only present in N. Its very noticeable while inside the cab with the windows up. I haven't had a chance to slide under while its doing making the noise to get my hands on it to feel for the source, the parking brake isn't adjusted yet.

 

does it still have the check valve in the transmission line?

 

Well, the check valve body is present. I know from web search that some will take out the check ball. I haven't removed it yet to determine it's state.

And I missed this earlier... it does have an external (factory) cooler that is mounted between the radiator and ac condenser.

 

A bit more research tells me that neutral tends to fill the torque converter rapidly. Perhaps that check valve is causing lower flow, and the pump is cavitating? I called the dealer to see if I could buy a replacement valve, they couldn't seem to come up with a part number that looked right. So I made a couple hours to hit the jyard and grabbed another check ball hose, that I'll gut and install in place of the one currently in there.... see if my noise goes away. Seems weird that I can't find someone else describing this symptom.

 

most people eliminate it all together as it is the cause of many transmissions letting go.. when I bought my SST the trans had been recently rebuilt
and the shop that did it for the PO/OO eliminated it and pointed to it as the cause of his trans failure

if you use the line that eliminates it you just have to remember to put it in neutral for about 30 seconds after starting
so it can build pressure before trying to drive off..

 

I grabbed another check valve,verified that it was clean and operational, and swapped it in. Problem persists. When I pulled the line, not too much fluid came out. Is that typical?

Other cheap ideas to check out? Can I tell if the PO put ATF+4 in it? Its still red.

 

I would be tempted to do a fluid and filter change, just because..... maybe the filter isn't quite tight, or maybe the pump can pull some air around it.... (although, that would tend to make you think it would noisy all the time......) If it ONLY does it in neutral, I wouldn't be spending a lot to try and fix it...... Not like I let my truck sit and idle in neutral very often.....

 

Yeah, I had the same idea about pulling the pan and swapping fluid. I am hopeful that I can find out the issue, and it won't entail dropping and rebuilding the whole transmission... I know, I did say hopeful.

I was searching youtube and came across a really kickaxe VERY complete rebuild series for the 46re transmission. I was very impressed with his video series. He sells rebuild kits and separate parts. Interestingly to my earlier question, the guy talks briefly about checking the cooling system. He isn't targeting the check valve, but is talking about the cooler causing fluid not to flow. Gives you a procedure to see if the trans fluid cooling system is clogged up or not. My truck has both the rad cooler and a factory aux cooler. So I guess that is an easy, and cheap test.

Also, for those that are interested in rebuilding... he even has directions on how to build out a couple jigs, wood ones for assembling and one for compressing lighter springs.... also has what looks like 3 welded bolts to compress the overdrive unit using a press on another video... pretty awesome video series.

Here is the video.
at 31:57 minutes:seconds

at about 34 minutes he shows how to make the wood jig