Jake719

I changed the transmission fluid and filter and installed a transmission cooler in my XJ (AW4 automatic) about a month ago and have started having issues with slippage ever since. At first it only happened while stopped at a stop sign or light, but in the last couple days it's slipped twice while driving. Mostly only happens when cold, but it has happened once with then engine warm, though not up to operating temp yet. Fluid was dark but still red, not black, and didn't smell very burnt, but it must have still had a decent amount of clutch fibers in it.
My guess is that it's happening either:
1) because I flushed too much of the old fluid out, lost the clutch fibers it contained, which is reducing friction and causing it to slip, or
2) because the trans cooler is making it take longer for the transmission & fluid to warm up. (I don't have a trans temp gauge, so this is difficult to assess.)

I suspect that answer #1 is the more likely scenario. My understanding is that as clutch fibers get worn into the new fluid it should slip less often, but mine has been doing the opposite - slippage has gotten worse and more frequent since the fluid change, so I'm considering adding a friction modifier to see if that helps.
I'm looking at either Lucas Oil or ATP AT-203 (links below). Does anyone have any experience using either of these additives or other friction modifiers? If so, what are the potential pros and cons of using a friction modifier and which would you recommend?
Or are there other troubleshooting methods I ought to attempt first/instead?

Thanks in advance for your input!

ATP AT-203: http://atpautomotive.com/friction-modifier
Lucas Oil Transmission Fix:

awg

the very first thing I would do is make absolutely certain that the level isnt low,
the most sure way being to add some fluid (1/2 to 1 liter), it can be easily drained if needed
I run my AW4 just above the top mark

IJM

Agreed on the checking the level first. Not to insult your intelligence, but did you check it hot while running in park (or neutral)? Also, did you use Dexron III/Mercon?

BlueRidgeMark

This. If you got advice at the parts counter, they likely told you the wrong thing.

As for harming a transmission by changing the fluid, nope. That's an old wive's tale.

Noah911

Hey Mark.

Do you know anything specifically personally with accidentally having put in the wrong type of transmission fluid in a Jeep? Will it cause foaming to be seen on the politicians stick, or I mean dipstick?

Do not power flush, or backwards flush an older transmission with some miles on it... A passive transmission fluid flush is the way to go.

As a side note - if you were to drain and flush the transfer case, it uses ATF fluid.. The fluid in the transfer case does not in any way share any of its fluids with the transmission. However, the torque converter does share the same fluid as what's in the Transmission.

Also, if you drain all of the transfer case fluid out before first removing the transfer case fluid filler hole bolt from out of the transfer case.. and then cannot get that filler hole bolt out? You will have to flip the Jeep upside down onto its roof in order to be able to fill the transfer case back up again through its drain hole. So, always remove the transfer case filler hole bolt first before draining out its fluid, to make sure it will come out okay!

Noah911

My buddy swears by, and uses the Lucas brand in his Ford van E250 transmission with good results. He says without it his Van's transmission slips really bad. He has been putting this same stuff in now for years..

I don't know if it would do the same in the Jeep transmission, or if there would be anything else to check first? Except for having the correct fluid level verified with the proper testing procedure. Also, making sure it is the correct fluid that is in there too.

BlueRidgeMark

Funny you should ask, sir. I did it to my Grand, and yes, I did get a foamy dipstick. I stupidly assumed it takes DexMerc and dumped in a quart. Now I know better.

I flushed it once, and may have to do it again. Still a bit of foam.

Noah911

I think it was my frst post to this site... maybe was the second post?

lawsoncl

When Chrysler switched to ATF4+, lots of people killed their trans by using Dexron. That certainly didn't help Chryslers reputation for unreliable transmissions.

For the OP, you should also check that the trans-throttlebody cable is properly adjusted. Too loose can cause slipping.

Jake719

So what I thought was the trans slipping was actually the engine stalling. The day after I posted this it became a lot worse and started sputtering and backfiring in idle. Check Engine light came on - got multiple codes for both O2 sensors. Took swapping both sensors, fixing the wiring to the front sensor, and swapping the O2 sensor heater fuse to get all the codes to clear, and now she's back to driving like normal. I appreciate everyone's input though, and the other threads also helped with solving the O2 sensor issue. These forums are an invaluable resource for newbies like me.
To satisfy your curiosities: I did use Dex/Merc - not ATF - when I changed the fluid, and the level was full (I checked with the Jeep at operating temp after shifting through all the gears). I think I'll take Noah's advice and just passive flush next time just to be safe.
Thanks, everyone!

BlueRidgeMark

Jake, thank you for not being a one-post wonder!

We appreciate the feedback.