Automatic transmission noise


#1

About a year ago, I had the automatic transmission replaced in my 1995 Dodge Dakota truck. (318cid, 3 speed with OD) All was well for about 6 months. Since the weather turned cold, on start-up, when I put the transmission in gear, it “moans” for about 5 seconds. I checked back with the transmission shop and they told me that in this replacement transmission, the fluid drains down during the night and that I should just allow the engine to run, in neutral, for about 5 minutes before putting it in gear. This seemed like a lame answer to me, but the shop is very reputable… Even if I allow a minute or two before putting it in gear, it still “moans” for about a second. Is this a potential problem? Do I need to wait before putting it in gear, and am I looking at another transmission job in the near future???


#2

This is defintely a potential problem and I would avoid driving the car until it is properly fixed. What you are told is pure BS in my opinion. I have driven automatic cars at -20F and there might be a short grunt during startup at that temperature, but it should not be necessary to run it in neutral for 5 minutes; I would take a minute at most at low temperatures, mainly to get the engine oil circulating.


#3

Actually, they are not BS’ing you. These transmissions do not circulate ATF when the gear selector is in park. This is why they told you to warm it up in neutral. You dont have to let it warm up for 5 minutes though. Thirty seconds to a minute in neutral is enough to charge the converter enough to drive it. There is also a check ball in the cooler line which keeps the torque converter from draining back during the night or after sitting a long time. These check balls sometimes leak or in worst case scenarios, they will plug up causing the transmission to burn up. You are experiencing what we call “converter drainback”. Heres what you can do. Either replace that check ball which is either leaking or the transmission shop removed it when they replaced the transmission. This is not uncommon. OR Have the transmission shop install a new updated manual valve in the valve body. This valve is made by a company called Sonnax, it allows converter charge while in park. This will do away with you having to idle in neutral to charge the converter. The valve replacement is very simple and can be done in about an hour just by dropping the pan. When this valve is installed you can permanently remove the check ball in the cooler line.

transman


#4

Great advice - Thanks