A/T moves slowly even at high rpm

Hi I recently was driving my tundra (4.7l 4x4 auto) when I noticed the rpms would fly up when I hit the gas while driving. They would go back to normal after a few seconds like it was going in and out of gear. A few minutes later I cam to a stop light and when the light turned green I couldn't go into gear at all. I pushed it into a parking lot to see what was going on and I noticed that if you rev it in gear it would move just very slowly even at 3 to 4k rpm.

Here is a link to a video of the driveshaft movement compared to the revs. (There is no drivshaft to the rear as I am waiting for parts to rebuild the rear differential)
https://photos.app.goo.gl/fF9DxrJR4FWtiwr3A

Any information as to what might be wrong will be appreciated, thank you.

 

Check fluid level

 

Fluid level is normal

 

Definitely a problem in the transmission here. Bad pump? Bad torque converter? Low fluid would be the most common problem, but you say it’s normal. What color is the fluid? What codes are being thrown?

 

Could be the converter, trans pump, check-balls getting stuck. I think dropping the trans is in your future.

 

Do I have this right that you were driving with the rear shaft disconnected? So in 4hi and using fwd? I think the transmission needed that resistance... Ive been wrong before tho

 

Just seeing that bit of info. How long have you been using the truck in 4x4 with no rear drive shaft?

 

That’s exactly what I was thinking. Usually that’s only done for diagnostic purposes. @empty_lord just recently did that himself troubleshooting some issue I believe.

 

Right? Blow a U-joint, limp it back home or to a safe location. Wouldn’t keep daily’ing it for sure.

 

Ive done for a few miles to get back to the trailer, it was brutal

 

You can without hurting anything


Assuming your not beating on it

 

I've been driving it in fwd since November and its driven perfect since then. It doesn't seem like that's the issue. Probably something electrical or the tc. Im planning on dropping the trans this week to diagnose it

 

What you are describing sounds exactly like a slipping trans. Probably going to have to pull transmission. Does it work in reverse?

 

Could it be a transfer case issue?

 

T-case chains make a helluva racket when they stretch enough to start jumping teeth. Hasnt happened to me, but i’ve heard it on other trucks.

 

Yeah I think trans is probably fine. You usually know it’s your trans when you get funny sounds and some smoke before it leaves you stranded. My vote is on the transfer case from driving consistently in 4 wheel.

 

unless the rear output still spins in 2wd. The planetary for 4lo or a stretched chain would make racket, a broken chain wouldnt have moved the truck a couple inches like i think it did.

fluid isnt flowing right. I’d guess pump, but it could be anything from the shift lever to the check balls. Need more info. But i like the sound of the glasspack.

maybe worn the splines off a shaft, or the shift fork, but transfer cases are really simple, and theres not alot to go wrong.

 

Maybe t-case is low on fluid or hasn’t had maintenance. When they go bad, they like to jump in and out of 4 wheel.

If the transmission isn’t flowing properly, you’d get some metal shavings from friction wouldn’t you? Maybe check the pan and see if you have a lot of buildup on the magnet.

 

In Op’s video, the rear shaft is spinning, and I’m assuming it’s in 2wd since the vehicles isn’t moving. Unless it’s on a lift or something .

 

It doesnt look like its spinning. Full rotation? Rocks it a little, but diff is still holding.

either the fluid isnt engaging, or trans is slipping hard. G’naded t-case would more likely lock up hard. Fluid couplings allow rock & roll.

 

I turned off the video after I saw it spin a little bit just to verify, but yeah, it wouldn’t get the diff moving at all.

Yes t-case would have hard lock up

 

Engine doesnt sound loaded enough.

kinda sounds barely more loaded than neutral. Pump, converter, or balls. 2 of those can be checked by pulling the cooler line. Or, it could be glazed, bald bands and clutches.

 

You’d probably get codes for burnt out clutches? I’ve always got codes for it on other vehicles that were smoked out. Also worn down clutches (in my experience) have always been able function in a half ass manner. Also usually worsens over time and doesn’t happen randomly at a stop light. You’ll usually see it coming you know

 

You’re right, but grandmas old e-series 30ft motorhome had huge chunks floating in the fluid. No clue how it kept driving. Put the slurry back in, and it kept running flawlessly for 10 years. Transmissions are mechanical magic. Sentient, only fail when they want to.

 

Big chunks for a big transmission haha!
I think those transmissions are like 6 feet long and as wide as a redwood tree
Also allison transmission? They make a lot of them for motorhomes.

 

So it sounds like our part-time 4wd T-cases are just that…part-time. Or can they be driven daily in 4wd every day as long as the road is acceptable for it?

I kind of wonder if putting the fully loaded weight of the truck on the front drivetrain is okay for just the front wheel drive portion of 4wd since it wasn’t designed to be used that way.

 

Awd t cases have clutch packs. 4wd is solid. Like gmc syclones had awd tcases from astrovans and olds bravadas and 4x4 s10s and blazers were solid.

 

I a s10 blazer, my buds was almost as tough as my ranger. Sorry off track again.

Thats what im thinking now also. No center diff and all that either

 

Also off track but I cracked my old transfer case on my 89 s10 going over big rocks in mountain roads
Since we’re talking about s10 transfer cases