I think I have a mechanic I can trust. But he flushed the tranny on our 98 SLX (90k mi) and BOOM! now it won't shift between 2nd and 3rd. I am told it "just happens sometimes!" Needs to be re-built! Anyone else? I can't find anything bad on these trannies on the internet. I want to be sure my $5k +/- investment is not because some body screwed up and is covering up! Thanks for your help in advance!

What's the service history on this tranny?

If the fluid has NEVER been changed before now, then yes, changing it at 90k can cause a failure as the fluid is WAY old. Especially if it was flushed = loosening up a lot of gunk and sending it to clog the passage ways.

These 4L30-E GM transmissions like their fluid changed every 25-30k miles; 90k miles with a complete fluid swap all at once can cause a failure for sure.

If the fluid had never been changed, your mechanic *should* have recommended a partial fluid swap WITH dropping the transmission pan, changing the filter and then adding new fluid.

Flushing the whole unserviced system at that many miles wigs it out, and clogs the torque convertor.

buy a used one and stick it in. 5k is a lot of cash to spend a truck that is probably only worth 5k.

check ebay and www.car-parts.com

WOW! I asked my wife to research the history. Looks like this service got by us! Dagnabit, I think you hit the nail on the head! I will share your insight with my mech. I think we will put a used tranny in, he quoted me $1,500 and said it takes 10 to 15 hours to swap them out. (Service here at the dealer is $160 p/h and he's at $110). Thanks for your input.

It's life; don't feel like you're the only one who's let something slip. Good luck to you.

Your right. $5k doesn't really work in my book. We bought the truck at 17K from a dealer as a used demo. All other services where covered/done. It's in top shape (if you overlook the tranny problem)! Looks like we goofed. Thanks for the link to the parts world. I'll pass it all along to the mech. He has serviced all my vehix for more than 3 years and I hate to loose/end a relationship based upon a bad assumption. I think I'll blame it on my wife (just kidding). Thanks

Also, look around for a junk-yard deal.

Dohhh.... I've got about 73k on mine and I can't remember changing the fluid either. What do you guys recommend? I'm in Bosnia, so theres no Isuzu dealership and this is an american model so now spares sittin' around either. At this time, knock on wood, I'm not having any problems. Is this partial fluid swap a shadetree job or does it require a mech? Should I just "let it ride" until I see some problems? Man, I got the heebee jeebee's now!!
Tom

Looks like we never changed the fluid. Since my last post I have talked with two transmission shops. One was a $$$ monger and the other was in line with the advise I got here. I would now ask a lot of questions of who ever is going to do the work and find a specialist who is reasonable. I'm going to let the tranny shop service and work on ALL my transmissions. My mech is reasonable but apparently not totally knowledgable. Good Luck..

Should I just "let it ride" until I see some problems? Man, I got the heebee jeebee's now!!
Tom

You do that, and you could be looking at the same situation of a failing transmission at 100k miles or so. These trannies typically don't make it much past 100k without good care and service.