I just cant understand how or why it went when it did. Was driving my car id say for about an hour or so. I wasnt beating the hell outa it.....but wasnt exactly babying it either. Just kinda fooling around with her. I was at a red light in OD and pulled a u turn to go back up the road and then all i got was the engine reving. Car wouldnt come outa first. So i kept tapping the throttle and then i feel a BAM.....car slammed into 2nd. It was obvious that the tranny was messed up or a mechanism blown. How come i never got like any type of warning sign at all. No knocks pings....noises...nothing. I mean i got my tranny rebuilt with all the goodies now....so i hope this wone happen again. But its just something ive wondered. I mean i guess having 130thou on it doesnt help.....but my brothers vette with 125thou did the exact same thing as mine did. No warning at all...jsut went. Any info on this???

 

Check the Govenor.

Parts just break. One minute they are engaged, then a few teeth snap off the gear and they arent.

Sounds like you Blew the teeth off the govenor Gear, to me.

 

I'll bet it was really third gear you hit, not second. First gear to third gear shift is a classic symptom of a busted 2-4 band. Yes, they do brake for no reason at all without warning.
Let me guess, you don't have 4th gear either?

 

Heat causes a good amount of failures in the TH700R4. Besides the good old shizt happens stuff a good LARGE transmission cooler will extend the life of any automatic transmission.

 

I don't know anyone with a 700R4 that hasn't had them self destruct. The one in my 82 blazer has been rebuilt twice (and I don't hot rod it, how can you hot rod a diesel??). Once by GM and once by an independent (they pointed out that the Chevy dealer had not made an effort to install the upgraded parts that were stock on the later 700R4's but warranty repairs are usually done as cheaply as they can get by with). In the 2 yrs. I've had my 86 IROC I haven't had a problem, but then I won't even consider ragging it like I do my 81Z28 with the muncie 4spd. I like the IROC, it runs good, get's great mileage, looks great, etc. I just don't trust the 700R4 like I do the muncie, or the turbo 350 in my 73 Laguna (now there's a car that got drove hard and put up wet and never let me down!). Everyone says the later 700R4's are better than the first 3 or 4 years. Maybe so.

 

it was weird when it went. Like i said before....started to rev and then BAM i believe it went into 2nd......might of been 3rd though. I drove it for about 15 min trying to see if i could get it into OD to get her home.....and i did. When i got her home the following morning me and my dad took her pulled the tranny pan down.....changed the pan gasket and trans filter....put it back together......put new fluid in....started it up.....same prob. Weird. What else really bothers me though....when i brough it to my tranny guy to get it rebuilt.....he told me someone had been inside it already.....besides me changing the filter.

 

700's will go bad for any and every reason at all. Let me ask you, when you were sitting at that redlight, did a squirrel run by you?? I bet that's what blew up u'r trans! I have had 3 different 700 trans' in my 83 TA powered by a 350 crate, and they all blew, I even just blew a fresh rebuild 350 after 100 Mi. So not only am I never putting another 700 in my car, i'm never putting another automatic in my car. But my money's on the squirrel for yours.

 

There's a few big problems out there, not too many are related to the trans. The 83-84 trannies, well, GM didn't quite have their design down yet- they break frequently. 85-86, they fixed 'em a little better, but the main problem was that the fluid pump would aerate the fluid into a foam, and the trans wouldn't get enough lubrication- everything burned up. This is exactly how my original GM transmission died. The pump starved for fluid, the metal pump gear ate into the aluminum case, and threw metal through the whole trans.

'87 came out with a redesigned fluid pump, and a few other improvements like an auxilary valve body- and '87 is usually thought of as the "minimum" year for longevity. Thru the years, GM constantly improved the 700r4. For instance, you can actually put certain updated parts into earlier year trannies- such as the redesigned accumulator pistons. So the newer trans you can get, the better it'll be made.

The other problem was mentioned- overheating. The 700r4, by design, runs hotter than other automatic trannies (like the 3 speed TH350). That's why a second trans cooler helps out so much. When a trans gets hot, the fluid breaks down! So because of the hotter trans, the fluid breaks down faster, and if you don't change that fluid yearly, you wind up with a burnt 700r4.

Final problem? Rebuilders. They don't want to touch the thing, and if they do, seems like nobody can get it right. I'm on my 2nd rebuilt 700r4 right now, and it wasn't right from the day I installed it. My first rebuild, a $1200 Lee Myles trans, lasted about a year and 5 months. Apparently nobody knows how to rebuild them! So this summer, I'm going to take a shot at rebuilding a junkyard one myself. Got all the books, might pick up a video, too... the main deal with assembling a 700r4 is to put everything back in proper order, and not upside down or backwards (or forgetting parts)! At the least, hell, I certainly can't do any worse! They say the biggest thing required for a trans rebuild is a long, clean (dirt/dust/lint-free) bench that you can lay the parts out onto. I don't have a large bench... hopefully plenty of labelled plastic bags will do.

One thing the 700r4 can't shake is it's reputation. But people forget that when the "bulletproof" TH-350 came out, all the hot rodders dumped the thing out and threw in the "reliable" Powerglide transmissions. Yep, the TH-350's were thought to be junk. 'Course, after so many years, the TH-350 was improved, and now it's a strong trans.