slippage after a t-case swap

[milenko]

Hey guys. I love this site and have used it many many times. I have an interesting issue that has me stumped. I have a 97 explorer sport edition. It has the 4.0 SOHC with an auto transmission. I was getting a clunking sound when the 4wd was put under stress. I took the t-case out (took it apart and sure enough the chain had been stretched) I installed a used t-case that I got from a local junk yard. Now my transmission is slipping!

When I dropped the t-case I lost a couple quarts of tranny fluid out of the output shaft on the transmission. At first, After I reinstalled the t-case the tranny would only slip and wouldn't move the vehicle, so I topped off the transmission fluid and it started working again. At first I also put ATF type F in the transfer case. And drove it for about 30 miles, after the truck started slipping I read on here that I shoulda used Merc. V. So I changed the fluid in the t-case and I still have slippage. It does not slip all the time, only when the truck gets good and warm (prolly 5-10 miles after start up). It slips in all gears (well I haven't noticed it slipping in R). At first it will only slip while switching gears i.e. from 3-4, if it gets hot enough it will slip all the time. I know this because I was driving on the interstate at 75 mph and it started slipping and I was barely able to limp it home.

Also, the 4 hi/low lights flash 6 times every few minutes. (the O/D lights flashed when the transmission fluid was low, now it is not flashing) I am assuming that this is the computer telling me that there is an issue with the t-case.

Well guys/gals, what do you think? Could I have gotten a bad transfer case from the junk yard? Or did I somehow torch my transmission. Any idea on where I should start? Thanks in advance.

 

[drdoom]

Sounds like the transmission, definitely go have the codes read right away. The flashing O/D OFF light means transmission trouble. You may have issues with the transfer case also, might want to check the two shaft speed sensors to see if they are dirty i.e. metal filings stuck to magnet. But I would be more concerned with the transmission.

 

[milenko]

Thank you so much for the quick reply. I took it to a transmission service center and they said that there were no codes to pull. A few days ago, after I topped off the transmission, I reset the computer by unhooking the neg. cable and the flashing O/D light never came back on (I assumed the computer was telling me that I needed to add tranny fluid). Right now, only the 4 HI/LOW lights are flashing. I do not understand how the lights are flashing, but their scanner did not pick up any codes, but that's what they said. Oh and they offered to rebuild my tranny for $2k.

I used the speed sensors from the front and rear shafts off my old t-case as well as the shift motor (the shift motor works and will flawlessly shift the t-case into 4 low, where I still get slippage), the new t-case did not come with them. I will pull them out tomorrow and give them a quick once over. The tranny did not slip before I swapped out the T-case.

Could I have knocked a sensor or broken gears or something when I dropped the t-case. I didn't notice any broken sensors or anything. Does anyone have anyother ideas that I should check when I go under the truck tomorrow?

 

[4wheeltom]

You didn't use the type F fluid when you topped off the tranny did you, that stuff will wipe out a late model tranny real quick

 

[milenko]

atf type F

I used maybe 1-2 CUPS before I stopped and decided I had better check to make sure I was using the right stuff. I didn't mention it because 2 cups in a 12 quart system shouldn't burn up the tranny in 30 miles. Right?

After the tranny started slipping I did do a flush on my transmission (put 9 quarts in, got 9 quarts back out, I know that's not a true flush). hoping that would solve the problem. As a side note, that tip about using 2 different 5 gallon buckets to flush the tranny from the cooler lines doesn't work. The mods should remove that thread.

 

[milenko]

update

Hey guys, so I dropped my tranny pan and only had a little bit of clutch material in the bottom. I replaced the filter and topped it off with merc 5. I also rebuilt my old transfer case and reinstalled that. After about 100 miles of driving there appears to be no slippage. Moral of the story, a bad t-case can make you think that your transmission is going out.