95 Suburban will not shift into any gear or reverse. Help!

Hi, I have a 95 Suburban that I bought this past summer. It has 350,000 miles on it. I do not know if the engine or transmission have ever had work but I suspect not based on the amount of oil that leaks out of the engine and the slight jerk it made when putting the tranny into drive or reverse.

One day my wife was driving along and it simply stopping moving forward. I towed it home. The engine will start and run fine, but no tranny gears at all. When moving the shifter the proper resistance is there and the linkage is hooked up (the tranny is getting the physical movement of the shift.) It will not shift into reverse, drive, 3rd, 2nd, or 1st. It makes no jerk that all trannys make when shifting into reverse or drive from park.

At the time it first happened I checked the fluid. It seemed it was way low. I added some. I eventually thought I got the level right but still no shifting.

After sitting it for about three months I got back to it recently. I checked the fluid level and it was a foot up the dipstick. I couldn't believe it so I checked it again twice more and it still was way too high. I then got to wondering if it was overfilled.

I removed the pan. I found that the bottom of the pan had a thicker layer of brown fluid, along with a mush ball of gray sludge around the magnet along with a porcupine's quill of metal on the sludge (each piece a few millimeters tall.)

The tranny mount was broken (maybe causing some of the jerk in shifting into park or reverse.) I drained out as much fluid as possible then held cardboard up to the tranny while blowing compressed air into any open holes/passages I could find to try to force more fluid out. I also plan to take the cooler lines off and blow them out as well. I have also wiped it down pretty good. I plan to test the solenoids for functionality. I tested the fuse to the tranny and it had power.

My question:

What are some likely causes for a no shift condition? Could a massive overfill of fluid cause this?

I eventually plan to pull the engine and tranny and rebuild them both. Nevertheless if I can fix this cheaply I'd like to get whatever miles out of it that I can first.

If you lost all of the gears at the same time, then I would suspect the front pump. Take the bottom line at the transmission and follow it to the radiator and disconnect it from the cooler and put it in a bottle and start the motor fotr a couple of seconds. If you see fluid coming in at a good rate, then it is not the pump, if no fluid movement, then most likely front pump is broke.

Dana, thank you for the information. I will look closely at the front pump. However, I must do it by inspecting the parts themselves as the tranny is now out of the vehicle and is partially disassembled and will soon be completely disassembled. I have the front pump out but not apart. I see nothing wrong with it by looking at the outside. I will open and clean and inspect it. I am doing a proper rebuild but on the cheap (Corvette servo, new separator plate, new bushings, seals, steels, clutches, boost valve, etc, etc--basically whatever it needs to be stock but better (no "performance" upgrades--I ain't racing the 'Burb.) I will also get a Shift Kit but will research better which to get. I don't plan on doing the Sonnex valve body fix. I will probably get some new springs where needed.

I will post if I find a faulty part.

Which Sonnax fix are you talking about for the valve body? As for the parts needed here to do this right the first time, let me know?

Well, I found out Dana was spot on. The pump parts inside were completely broken! The black ring that holds the vanes was in two pieces and several vanes were broken. A mess inside. I found much damage to the tranny overall. I am replacing the entire planetary area inner and outer. New sun shell, new bushings, and lots of other things. Basically whatever it needs.

The Sonnex fix I did not want to do involved reaming the hole and what not (I don't have the equipment to do that properly.) I used the Transgo Shift Kit which seems to have most of the valve body issues covered.