I looked over this paper of what was done to my 97' when they sold it to me and saw that when the trans fluid was flushed they put synthetic fliud in. Could this be why it slips on occation?

Not sure of the fluid (do you know which brand?) but the flush may have dislodged some debris that got hung up and is making the tranny slip?
Consult a tranny shop and look into another flush and specify dex III tranny fluuid.

Personally, I would never let anyone flush my trans. It in itself may be your problem. Here is a quote from a GM powertrain engineer that I have come to know and respect from another board.

"Noticed this gem on another forum and wanted to share it here... just one more in the long litany of dissatified transmission "flushers".....


I have a similar problem, saturday the tranny started slipping, not all the time and only from a stop, once moving the thing was solid. yesterday morning i was halfway to work and taking off from a stop light the thing would barely engage, rev-ed it enough to get out of traffic (very angry rush hour traffic) and got to a parking lot to call work, i tried to move the car again and it worked fine, again shifting fine while moving, no slippage, etc. Only to crap out again further down the road. I had the tranny flushed a month or so ago at a quick lube type place and the filter was not replaced, thought maybe that was causing a problem. nursed it to a garage next to work and they replaced the filter/fluid (everything was clean in the tranny, no metal pieces parts floating around), but when i picked it up it would not engage at all. So, what do you think, is the tranny gone? i towed it and ordered a Jasper trans ($1872.00) but have a week before that is in. Is R&R the tranny a little overkill? this is a '93 eldo (4.9) with 140k on it.



You are just the next person in the litany of people who have had their trans "flushed" in good faith only ot have the trans fail catostropically within a few weeks. It happens a lot. That is why I steadfastly recommend to people to NEVER have a transmission "flushed" at a shop or quickie oil change. You probably got some debris into the trans from dirty oil from the flushing equipment, debris in a line from the equipment from the last trans flushed, etc...or it stirred up some sort of debris that was in your trans that got in a valve and stuck it. Very very common to have happen if you start stirring things up. Sorry it happened to you but it is very common with flushes. They are nothing but moneymakers for oil change places...and transmission shops a few weeks later....

I would guess that your trans was OK but a valve is stuck in the valve body...if someone could pull the valve body and clean it out it might work again...but if you tried to move it (revving it as described) it may have destroyed a clutch pack in the process. The replacement trans may b e your best bet. I think that I would stop at the oil change place that did the "flush" and ask them what they are going to do about it. To coincidental to blame on fate.....

Think about the flush... most everyone ignores their trans until it starts to slip or act up...so...they rush to the oil change place to have the trans "flushed" in the fervent hope that it will cure the problem. So, there is a very high likelyhood that the last trans that was hooked to that flush equipment was failing and generating debris...which you may have in your trans now. Would you get a blood transfusion from an unknown source...???"

Ranger, Good Job on presenting this data. -about says it all.

This whole "flushing" idea always sounded mighty risky to me, and now my suspicions are confirmed.

Thanks !!

I'll give you the other side. I've had 4 flushes on this car (3 professionally, one by myself), all with EXCELLENT results.

Synthetic fluid would be the culprit I'd look at. We don't have good luck with it at all. If it were my car, I'd get it out of there. When your friction material on the bands is already worn, the synthetic fluid can make it slip worse.

And yes, I have a scantool to completely diagnose my slip and shifting before and after each flush. This tranny would have been dead 6 months ago without the flushes.

That'* because you had enough metal shavings in your pan to make a new damn transmission!


-justin

Only the last time. The 3 professional flushes had no metal.

i am surprised that a flushing machine wouldnt have a filter in it to get rid of the debris from the last trans...

It doesn't need one. The flushing machine they use on my car has my trans output attached to the bottom. It forces fluid to the bottom side of a big piston in a cylinder (clear cylinder, so you can see the fluid). Above the fully retracted cylinder is 12 quarts of trans fluid. The pressure from my trans pushes up on the cylinder, forcing the new fluid in.

This prevents mixing fluids. They're isolated for every use.

Wonder what made it fail?


-justin