how do i know if my 700r4 tranmission is going out?

Question

i have an 86 chevy 1/2 ton 4x4 with a 700r4 tranny. one day it shifted fine through all 4 gears and the next day it wouldn't take 2nd or od. any suggestions?

Answer 1

What does the fluid look and smell like ? dark and burnt , it's time for an overhaul.
There are 2 bands in it and one could have broken . it's time for an overhaul.
The 700R4 has smaller clutches than a TH350 and therefore has harder time of handling the stresses of 4x4 or racing and needs all the upgrades available. it's time for an overhaul.
Most anything done for repairs other than cable replacement or filter requires an overhaul.

Answer 2

Sounds like you have an internal seal failure, based on your description. The key is sudden failure. 1986 is an old unit. Frequent transmission fluid changes may have helped it last a little longer, frequent like every other oil change, but time will eventually result in a failure of some sort. The internal seals are made of rubber, and become brittle with time and heat, pressure and the chemicals from fluid. A pressure test will reveal the problem. You can either perform the test yourself, or take it to a specialist.

Answer 3

First how many miles? How many transmission services? Should have been serviced every 30,000 miles. First drop the pan and see how much metal is in the pan. There's a magnet in the pan so you'll see right away. If there is just some shavings, flush the transmission, change the filter and gasket. If you don't know about the service. Best to drive it alittle bit and service it again. Don't forget the filter the second time. If it's salvageable that should do it.

Answer 4

i own a repair shop,and if you have already checked the fluid on it then you know its full you,ll need to check,and see if it smells burnt,or has a brownish color to it,if so this means it is burnt and the clutches,and bands may be shot in it,usually they,ll give some kind of a warning ,but on some occasions they,ll go out like a light bulb ,so you might want to take it by a transmission shop,and have them look at it,,they might can tell you what happened ,and why it happened,this is the best thing to do at this point,,good luck,i hope this help,s.

Answer 5

Try changing the fluid first and flush it out, you might get lucky. If not you may need to get it rebuilt. 700r4 is a good transmission and worth getting rebuilt.

Answer 6

if 2-4 band is burn`t out you won`t have 2nd or od only ist and 3rd broken sun shell no reverse ,second or od .

Answer 7

possibly low fluid fluid pressure, check by bypassing cooler in radiator with rubber line & clamps.drive 2-3 miles. better? replace with auxillary cooler.