Engine/Transmission (1994 - 1998) Initial symmptoms of low auto tramsmission fluid

[SDrake]

94 Cummins auto transmission. With a slow leak, what are the first symptoms or warnings that oil is getting low? Does it first affect shifting, torque converter lockup or does it just start pulling rough? some of you may have lived through that. I am just wondering if there is any warning before the damage is done. And if caught early where is the damage contained to.

 

[fox]

I've seen them suck air and feel like it went into neutral breifly.

 

[fest3er]

Some years back, my '98 had a leak: all of the pan bolts were 1. 5 turns loose. The trans may sometimes seem like it is hitting neutral momentarily, especially if you are doing something to cause the fluid to slosh around thus making the sump momentarily run dry. Shifting gears or engaging the TC clutch may seem to take 'longer'. Going uphill, the clutches and bands inside can slip (due to insufficient pressure) whilst accelerating uphill with the TCC locked. You may only see a momentary slippage because the TV increases the system pressure as you push the pedal closer to the wood (via the TV cable).

Mine did that sort of thing from SW VA all the way to Briar Hopper's open house and back. Since I was paying attention, there doesn't seem to have been any permanent damage. The TC looked new when it was later replaced with a purple one (ATS). The filter looked good and there was nothing else obviously wrong. That was close to 150K miles ago. Other than occasional filter/fluid changes, putting the ATS VB and TC in, and using Amsoil in it, the trans has been untouched in 12 years/270K miles. And since the stock fluid is synthetic, the trans should survive a fair bit of incidental slippage. Remember that clutches and bands slip every time they engage and disengage; slightly, but they slip.

 

[Vaughn MacKenzie]

On 1-2 upshift mine would do the quick "neutral" thing too, but other than that acted totally normal. This was when it was almost 4 quarts low.

 

[SDrake]

Thanks, I have a cooling hose leaking and can't get to it for repair for a week or so. I am going to check fluid level and drive on. It was almost 3 quarts low from who knows when but I checked it because I thought I felt something let loose momentarily, (going into neutral) wasn't sure if it was not just the road but checked level and was low. The leak must be small bacause I do not get a drip on the driveway but can see where it is being spread around underneath by the highway air speeds. But when it is idling it only weeps a little.