Need new transmission????

[kplusten]

Took 99 Trooper to dealer with check trans lite and check engine lites on. Technician says code is 1870 (internal slipping), and I need a new tranny. Vehicle has 70K miles and runs/drives perfectly. Should I "jump off the cliff" or have them reset the code, do a tranny service and see if it repeats? New tranny seems pretty drastic diagnosis...tech hadn't even driven car or checked color of trans fluid, band wear by opening one of the two bolts on pan. I bought vehicle used so have no confidence in previous servicing. Any advice out there?

[keithramsay]

Take your trooper to the local place that specializes in transmission work. Explain the situation to them, and see what they say. It won't cost anything, and if they agree that you need transmission work, they will give you an estimate for free.

[rodeo02]

I would do a JUST a transmission pan drop & filter change, drive the truck for a week or two & see if the issue persists. This will change atleast half of the ATF in the system, give you clean, free flowing filtration & allow you or a shop to see inside. If the concern slows or stops, I would then do a full ATF swap to see if the problem stops. You cannot stretch ATF changes in the 4L30E. Do not go beyond 30-40Kmi on the same ATF with these units.
G/luck
Joel