Hello, im not trying to get an exact answer just some possible culprits. My dad was driving his 1988 k2500 with the 700r4. He said it felt like it was slipping on the 1-2 shift. A few miles later it lost all gears and rolled backwards when you gave it gas. The transmission was a re manufactured unit from gm that was installed maybe 4 years ago. what are some common issues or parts that could cause this problem?
700r4 lost all gears.
- Thread starter joegreen
- Start date
Low on trans fluid or maybe the trans filter was plugged up. Ask him if he always drove around in the vehicle with the transmission in overdrive. Something tells me that this k2500 is a heavy vehicle, what happened to the original transmission?
^^X2, Always check fluid level first!!
Catastrophic front pump failure is somewhat common on 700R4's, I always install TransGo Pump Rings or 4L60E Pump Rings.
Another somewhat common failure is the Torque Converter coming apart. More specifically the Torrington Bearing failing & filling the unit with aluminum shavings thus stopping up the filter......It will usually move under it's own power once it sits long enough to release some of the blockage.
Catastrophic front pump failure is somewhat common on 700R4's, I always install TransGo Pump Rings or 4L60E Pump Rings.
Another somewhat common failure is the Torque Converter coming apart. More specifically the Torrington Bearing failing & filling the unit with aluminum shavings thus stopping up the filter......It will usually move under it's own power once it sits long enough to release some of the blockage.
The fluid was at the appropriate level. He pulled over and checked the fluid and the tv cable. Yes the truck is quite heavy. It's loaded with tools, has custom tool boxes built into the bed sides, has a plow frame on it, a cap with a bunch of ladders on top and he was pulling a trailer at the time of failure.
What brand of transmission fluid is in there now, and how many miles are on this transmission?
I think it has ac Delco dex6. The odometer broke so no idea on mileage
- Joined
- Jul 16, 2020
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Check line pressure at port if zero pump is gone and or plugged filter. If Good clutches gone. Good like may the force be with you.
Until it is built and cooled right the 700R4/4L60 is a POS, took 5 times to get mine right. GM rebuilds although have a great warranty- repair what is wrong with the trans and send them on their way. TV cable should be set by line pressure.
Dexron VI may be too low a viscosity grade for a 1988 .
Lower viscosity oils contributes to lower pressure reading , and may hasten mechanical wear .
Thanks for “ the rest of the story”. So many posters are never report back.
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