AUTO Transmission popping out of gear

[ChrisInVT]

This is a new one for me. Every-so-often, the transmission in my '89 box truck w/ the 3VZ will "pop" out of gear. It's exactly like what happens in a manual transmission, it just jumps out-of-gear like it's in neutral. This happened first about a week ago. I pulled up to a stop sign, let off the brake and hit the gas, and the truck didn't go anywhere, just revved up really high - and then it "remembered" it was in drive and banged into gear. I thought maybe the shifter wasn't fully in drive, but it most definitely was.

Fast forward to yesterday. I was at a store with the truck on a slight incline trying to pull out of the parking lot and onto the road. I was waiting for traffic to pass, and when there was none I let off the brake. Truck didn't roll backwards but as soon as I hit the gas the engine revved up and the truck started rolling backwards!!! It scared THE CRAP out of me. I slammed on the brakes, and once again checked to make sure the shifter was in drive (which it was). While I was pressing the brakes, I pressed the gas and the truck wanted to move - so I let off the brakes and pulled away.

Fast forward a bit to 4 hours later. I'm on my way home driving through town... I'm going up a hill and an idiot dead stops in front of me to make a turn. I stop, and the idiot turns. I hit the gas and start to drive away, and within one second, I the engine revs up and the truck stops moving forward, but then jumps back into gear and drives normally.

This is pissing me off. Transmission shifts and acts normal, no issues other than this. After hour of searching all I can find is to replace the "shift lever bushing" but it only seems to apply to manual transmissions. My first thought was possibly the shift cable, because if I manually put the truck in 1st of 2n gear there doesn't seem to be any "slop" in the driveline - and it also doesn't seem to have this problem (although I haven't had the chance to test this theory TOO much - since this problem is random).

Anyone have any other things to look at? I'm going to look at the shift cable today if I get the chance, but it goes in PRN21 fine without jumping out of gear, so I dunno.

[Maineah]

Chris it sounds like the fluid is low fairly classic example.

[Derek up North]

I'll second that.

[Gulfstream Greg]

Valve body valve sticking?

[ChrisInVT]

I checked the fluid last week, and it was at the right level. I looked today and there was a puddle underneath my truck after being in a store for a few minutes. It was transmission fluid. A LOT of transmission fluid. I checked my dipstick with the truck warm, on level ground, running in park - and it showed the level was OK. I waited a few minutes and checked it again, and it didn't even register on the dipstick. I waited a few more minutes again, and checked it - and it showed full.

VERY annoyed, when I got home I swapped the dipstick from the camper and the box truck. They're supposed to look the same, but the one from the box truck was screwed up. The zig-zags at the top were all sorts of messed up. I checked the fluid again after this, and it showed it was low. I added two quarts and it's at the level it's supposed to be when hot. I'll see if this fixes the problem (I'm hoping). I've fixed the leak already, it was where the rubber hose meats the metal line on the external transmission filter. I have this same leak on my car, where the rubber hose meets the metal line on the transmission cooler. I've had that car for 5 years and put 60,000 miles on it and no matter what I do I can't get it to stop leaking. I guess I'll need to be more religious on checking my fluids. Instead of every 500 miles I'm going to make a habit of checking every Sunday.

Wish me luck on that was the problem. Leaky transmission line and a messed up dipstick. It doesn't surprise me because I usually have to fight with that thing for 5 or 10 minutes to get it back into the transmission. Both dipsticks on the camper just slide right in. And both dipsticks on the box truck I have to fight with for 5 minutes. I think I need to find a new/used dipstick and tube.

I went to the autoparts store today to get a gasket and filter so I could drop the pan, and they didn't have any; and couldn't get one. It seems to be such a PITA to get parts for this truck. I'll have to go to UHAUL's website and see if they sell any type of transmission service kits. I need to get order myself some tires from UHAUL, possibly some pads, rotors, drums and shoes while I'm at it... Brakes are getting kinda shaky.

[ChrisInVT]

Well, I have yet to replace the dipstick, but when I get the camper in the shop and fix the frame I'm going to have to actually start looking. After tightening up the clamps on the remote transmission filter, it's still leaking profusely. I thought the leak was there, but now I'm thinking the pan is rusted where the crossmember touches it. Might be a hole from abrasion when the frame twists and divetrain moves. Regardless, I'm going to remove the crossmember and take a look.

EDIT:

Put the truck up on the lift and within a little while this was under it

I was suspecting this crossmember as the problem all along

Crossmember removed and wiped down. That's A LOT of abrasion to eat into it like that

Wiped the pan down, and have this nice steady drip. This was instantly

And this is lovely. I had the WHOLE interior out of the truck last October, and there was no rust on the floor AT ALL. Now there's a huge hole!

[ChrisInVT]

Well there's my problem:

[WME]

Do you have a collapsed mtr mount??

[Gulfstream Greg]

I second the bad motormount or mounts.

[ChrisInVT]

I don't think it's a motor mount, because the crossbrace that I removed looked like it had a little bit of rock rash. If you look *really* close in the pictures, you can see it's tweaked a little bit.

[Maineah]

With a good transmission mount there is a fair of clearance between the cross bar and the pan.

[ChrisInVT]

Still unable to find a pan for this thing, it's leaking about a quart every few days. It's getting REALLY expensive even to have it just sitting. Anyone have one lying around (No, there's no local junkyards and even if there were everyone in new england sold their toyota for scrap)

[WME]

Take the pan off and take it to a welding shop and have it brazed up.

[waiter]

I've also used JB Weld. clean the area with Acetone or MEK, scratch with 120 sand paper, put a glob of JB on it, cure it with a hair dryer. last longer than any weld.

John Mc

88 Dolphin 4 Auto

[ChrisInVT]

I was thinking of pulling and welding it, but I only have a MIG and that pan is Aluminum right? Once I pull that pan I'm no longer mobile, I daily drive this thing.

I already have JB Weld on there, and although it worked great for a little while, it started leaking profusely after a few months.

I don't want to steal any drivetrain parts off the camper for this thing, I've already raped the cab interior for a whole bunch of stuff.

[WME]

The pan should be steel, so MIG is fine with a light touch.

Got a magnet???

[ChrisInVT]

The pan should be steel, so MIG is fine with a light touch.

Got a magnet???

Awesome, I'll attack it with my MIG on the lowest power setting. I've been using the MIG a BUNCH lately replacing the floor pans (oh what fun that's been) so that'll be a quick job.

Are you thinking a magnet to put in the pan to catch the fine metal shavings from normal wear? If so, I have some super powerful magnets (magnasavers, look them up on fleabay. These things will suck a ratchet out of your had from about a foot away) attached to the axillary transmission filter.

[WME]

What I was thinking with the magnet is to tell you if the pan is steel.

[ChrisInVT]

Oh, duh.