Auto-Rx Customers Questions & Answers

Two points to consider:

1) I had that 4T60-E in my 1993 buick century and autorx fixed a similar problem. 
See my post from 2 years ago

2) You are treading new ground by using autorx in such an old transmission, one that is having problems.  Two years ago I got lucky, and hopefully you will too, but make note of the risks right now in that any change you make to the fluid might possibly make this transmission undriveable.  This applies to just changing the fluid, or to adding autorx.  In either case the below can happen:

When autorx is used to fix an engine seal leak (we'll get to transmissions in a minute), it removes sludge from between the seal and its mating surface but because the seal is mis-shapen, the gap between the seal and the surrounding metal is now larger than it was before, since the sludge was partially blocking this gap before autorx removed it.  So sometimes when autorx is used to stop a leak, it starts by increasing the leak.  Then later, after perhaps 1000 miles or more as the seal is no longer under a blanket of sludge and has had 1000 miles to breathe itself back into its normal shape, it is at this point that the leak stops.

One way that a transmission is different than an engine is the use of internal suction and fluid pressure in the shifting process.  The transmission has internal seals that make this possible and when they start to leak, instead of seeing a new oil spot on the driveway, you experience a loss of the ability to shift due to the loss of suction. Your current problem is that the internal pressure needed to engage into drive is not happening until that seal is just large enough to close a gap and create pressure, and right now the seal is responding to warmth by getting just a little fatter when its warm, and that's when your car is becoming driveable.  Imagine that this seal also has a thin layer of sludge on it.  When you use autorx you will remove that thin layer.  In an engine, removing that thin layer will increase an oil leak, but in a transmission removing that layer will increase the internal gap, and now even warming your fluid cannot make the seal expand enough to close the gap and create internal pressure.  Now, in 1000 miles that seal would reshape and you would be good to go, however if your car can't engage how are you going to drive that 1000 miles, and give the seal the time it needs to reshape?  So that's the risk - being stuck with a car that won't engage.  I guess if it comes to that you could idle the car all day while shifting gears, giving the seal some time to expand. 

Meantime I think your best bet is to follow the normal transmission treatment.
Link to transmission treatment instructions


-- Edited by johnoh on Wednesday 9th of March 2011 10:41:27 AM