1999 Jeep Wrangler Automatic transmission started slipping

AKWILLY

MEMBER
1999 JEEP WRANGLER
6 CYL
4WD
AUTOMATIC
82,000 MILES

I was out last weekend playing with my new jeep and managed to get it stuck in some mud and water. It was submerged for about 15-20 min running with the muffler just under the surface. After being tugged out I went through a small mudhole to get back on the trail and the transmission seemed to slip out of gear in the middle of the mud. I pulled it back a few feet to dry ground and checked the fluid, and it seemed fine. I waited for a few minutes and started it up and it took off but seemed to stay in first or second gear. Then it just seemed to go into neutral, and I could not get any gears. I could start out in park and go through all the gears as if nothing was on the other end. I tapped the gas lightly while in drive and after a second the transmission started to engage very slightly, but then went back to neutral (or something)
The engine and tranny was running perfect on the freeway and around town for a few hundred miles. I just bought it from the orig owner with 82000. Never off road (until last weekend) It is stock and with 31in tires. It does sit low to the ground but nothing appeared to be bent, broke, or disconnected when looking underneath at the tranny and underbody. I am considering changing the tranny fluid first and see if that helps. Please

5 Replies

JAMES W.

MECHANIC
2,395 POSTS

I never hurts to change fluid and filter after 50K on any vehicle. This may or may not solve your problem. But, while you're under there, be sure all the wiring connections are clean and secure. This is where you will probably find your problem. Let us know.

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Friday, December 12th, 2008 AT 11:20 PM

AKWILLY

MEMBER
3 POSTS

Thank you for your quick reply. I checked the fluid again last night, and it seemed a little milky (foamy)
The fluid level looks fine. It did look a little dirty at the bottom of the dipstick when cleaned with a towel.
I put the tranny in gear and it seems to take a few seconds (or by giving just a little gas), then the tires begin to move (vehicle is up on jacks stands)
2 of 3 times I could get to about 15mph @ 1500 rpms and that was about all the tranny would do before seeming to slipp back into neutral. No cluncking or jarring.
If I put the car into reverse the tranny makes a constant slight slipping noise almost like it isnt fully engaged into gear. If I go from reverse to neutral the slipping noise continues while in neutral, but then goes away when put into drive.

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Saturday, December 13th, 2008 AT 11:27 AM

JAMES W.

MECHANIC
2,395 POSTS

If the trans fluid looks foamy or milkly, that is indicitive of water contamination. Apparently you haven't pulled the pan and drained the fluid yet. In pulling the pan, you will lose only about 3 qts of fuid. The fluid capacity, with the Torque convertor is about 7 quarts, so you may have to empty the pan a couple more times to purge most of the water in the system. I wouldn't even start the vehicle again until the fluid has been changed. The noise you are hearing may be the pump, or you may have "toasted" the low clutch pack. We will be able to tell a lot about what has happened by what is laying in the pan. Please advise.

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Saturday, December 13th, 2008 AT 12:11 PM

AKWILLY

MEMBER
3 POSTS

When you say to empty the pan a few more times to get all the fluid out, would you please explain. Do I need to empty fluid in pan, put pan back on, start, then pull pan again, etc, until all 7 qrts are out? I have enough new atf4 to flush out the tranny. I bought some cheaper stuff to use for flushing. Is it ok to put back on the old gasket and filter until I have drained all the fluid out, then replace the filter and gasket once all fluid looks free of water? A old jeeper friend told me that if there is water in the tranny it would most likely be coming from the radiator as the tranny is completely sealed. I read on some other forums about a drain hole on the top of the tranny that is known for getting water in the tranny if the vehicle is in the water too far. Do you have any thoughts on that? Would you say to replace the radiator? Thanks James

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Sunday, December 14th, 2008 AT 1:25 PM

JAMES W.

MECHANIC
2,395 POSTS

Your old jeeper friend is correct, on a rare occasion, coolant from the radiator can enter the trans coolant lines and get into the trany. But, I doubt this is how this happened. Towards the top of the trans is a vent for pressure relief. When a warm transmission is submerged in cool water for any length of time, the cooling effect draws water in through the vent. What I would do is, after the trans has sat for a while, pull the pan and filter. Drain as much fluid as you can. Paying close attention to what is in the bottom of the pan. Install the new filter and gasket without glueing the new gasket to the trans, just snugging the pan bolts. Fill the trany to proper level and try it to see if it works. At this point, we don't know if it works until you try it. If everything seems to work ok, then, I would drain the pan again, reusing the new filter and drive it for a few days. At some future point, I'd drain the trans again, using the same filter, and you should be good to go. Keep in mind, water is heavier than ATF, and any water in the system is going to settle out in the pan if the vehicle sits. Judging from your first posting, I'd say you have about a 50/50 chance of no internal damage. What's laying in the pan will tell the story. Let me know.