2000 Limited 4x4 Transmission problem

[firstbat71]

258,000 miles on the truck never had a problem. But now there is no reverse gear...I put the truck in reverse nothing happens..it acts as if it's in neutral and rolls freely. Gears in forward all work except a strange problem with overdrive. When I get to 49mph the shift to overdrive does occur...but the rpm drop is much less than before. The rpms drop about 100 rpms when it used to drop ALOT more. So at 65 mph driving to work the rpm is at 3400. Revs too high burning too much fuel. And when I am cruising at any speed and let off the gas..the rpms immediately drop to 750 like it was in neutral. If i give it gas again the rpms climb to 3400 and seems to catch and never slips. Any idea what this might be. No lights on the dash and i have driven it like this for almost 2 years lol. But now i'd like to fix it.

 

[thegipper]

Start with the basics, check your fluid. Is it burnt, old, low or too much fluid?

You could drop the pan and see whats going on. If its full of metal, time for a new tranny.

Sounds like your torque converter may be on its way out.

 

[pauldub]

Possibly a failed or failing shift solenoid. They are easy to replace but make sure there's a bad one before replacing. You can check the resistance of the solenoid coil to assess whether they are bad or not.

 

[thegipper]

Reverse is purely a mechanical thing and does not involve any shift solenoids. If reverse isn't working, something else is going on unfortunately.

Sent from my SM-N950U using Tapatalk

 

[firstbat71]

I removed the pan and the filter and 4 bolts were on the bottom of the pan. Most of the black coating on the inside of the pan had peeled off and one of the cork gaskets on the filter is missing. Possibly sucked into the valve body? The whole bottom of the pan had lightly rusted somehow. I installed a new filter and put about 6 quarts back in. Started it up and prayed for reverse...it started to shift into reverse and stopped halfway...then right back to where it was before..as if it was in neutral.

Possibly a piece of the filter gasket stuck in the valve body? Im thinking about removing the valve body and looking for debris. Any suggestions?

 

[thegipper]

At this point, you got nothing to lose. I'd pull the valve body and see if its blocked or something.

When you say the bottom of the pan rusted, was it rusted on the inside? If it is, that's crazy and I cannot think of how that would happen.

Did you figure out where the 4 bolts went to?

 

[firstbat71]

Yes the 4 bolts are for the filter. When I took the pan off the 4 bolts and filter were laying on the bottom of the pan. I dont know how the rust got there either...all of the black coating had peeled off and the inside of the pan was orange colored...rust. Two of the filter cork gaskets were also on the bottom of the pan, i couldnt find the 3rd gasket. The fluid has to be contaminated so tomorrow im going to try flushing all of the fluid a quart at a time. Ordering a new pan as well if I can get reverse to work again.

 

[thegipper]

If the filter was off (however the hell that happened) i think it may have starved the tranny of fluid. The tranny pulls fluid from the pickup at the bottom of the filter, if it wasn't attached it wouldn't be able to draw fluid like normal.

It's possible while the fluid was sloshing around, that the gasket did get sucked up into the valve body and may be blocking something.

Like I said, at this point, you got nothing to lose so I'd pull the valve body. Just make sure you put it back together correctly.

Let us know what you find, this is a crazy one...

 

[octanejunkie]

The filter is the pickup, so if it wasn't connected it was probably starving for fluid. Assuming the fluid level is correct I would check the trans fluid pressure to see if you have a weak/failing pump - reverse requires more fluid pressure than other gears. Perhaps there is gasket material in the passages, so dropping the valve body would make sense. Possibly even a reverse flush once the valve body is removed, you want to be careful not to blow particles into the valve body as the tolerances there are critical to operation.

I would also consider changing the trans fluid and watching your trans fluid temps, if you have a reader, IR thermometer or gauge hooked up. The fact that there is rust is a red flag, maybe the PO swapped trans pans opting for a rusty one and and didn't install the filter correctly; which would account for a lot of what you described.

Either way, good luck

 

[T4R2014]

At this point you don't have much to lose. You might fix it, but once a major mechanical component suffers an issue this severe, it chases your ass until you replace the whole unit. Just my experience. Who knows, it might get fixed and last another 150k.

 

[firstbat71]

I have not done anything to fix this for months. I figured the worst and decided to keep driving it until it won't move anymore and then buy a new vehicle. But today I get in and put it in R just for the reverse light...and it goes into reverse. Overdrive is back as well...i'm at 2100 rpm at 70mph instead of almost 4000 rpm. Maybe something was stuck in valve body and broke loose?