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TF-999 Reverse trouble

5K views 15 replies 5 participants last post by  Nubby55 
#1 ·
I have an 88 YJ automatic with 70K that will only go into reverse after it has been driven for 5+ minutes. The fluid is new and full, the filter is fresh, and the bands are properly adjusted. No one locally can seem to figure out what is going on.

When cold or parked for more than a few mins, the column shifter goes into reverse, and the detent can be felt, but no clunk. I can rev the engine with no sign of movement - as if it were in neutral. I have tried every combination of gear selection order to see if it will catch to no avail. Put it in 1/2/D and no issue going forward. A few minutes of driving around and reverse works like a champ.

Has anyone here had/fixed this issue? I am good 95% of the time backing into parking spots and avoiding situations where I will need reverse when cold, but there are inevitably situations where it is a pain. Any advice would be appreciated. Thanks!
 
#5 ·
#1 - The shifter goes into reverse smoothly. There just is no "clunk" and the engine will just rev as if it was in neutral.

#2 - I bought it recently. The previous owner said it had been this way for a few years. He did not mention if it was sudden onset or gradual. He did indicate that the bands were both adjusted last year and that did not help.

#3 - The jeep doesn't leak a drop of anything.

If I drive at least 10 miles it seems to do the trick, and goes into reverse like you would expect. I just cannot figure out why a "cold" transmission would prevent the engagement.

Thank you for your time.
 
#8 ·
Only 70K on the Jeep, including transmission. It shifts exactly when needed and does so smoothly. I have in my notes from the prev owner that it had a fresh fill of ATF+4 at the same time as the band adjustment a year ago. I have read a mixture of opinions on the appropriate fluid. Could the ATF+4 have this effect?
 
#9 ·
No atf+3 is the recommended fluid for your transmission and atf+4 is a synthetic newer type that is backward compatible with atf+3. If it works fine when warm, it could just mean the valve body is a little gummed up or the pump is not working well until it is warmed up. Most problems with the tf999 are pump related and are fixed when the pump is rebuilt.
 
#12 ·
That issue would bug me so bad that I would dump a can of transmission flush in it and drive it around until the reverse worked. Then change the fluid and filter.
If that didn't work, I'd buy and install a new or rebuilt pump myself and clean the valve body at the same time. I might even do it when I changed the fluid & filter after the flush, just to save the double labor of dropping the pan.
I've done very little automatic transmission work, but feel confident that I could do the above with the help of a Factory service manual.
If that didn't work, then off to AAMCO or whatever transmission shop is in your area. I wouldn't abide the embarrassment and frustration of being stuck with my nose pointed slightly downhill when I wanted to get on with my day.

For me, the cost of rebuilding or replacing the transmission would be worth getting rid of the aggravation.

Good Luck, L.M.
 
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