Hey guys, got a transmission question for ya. I just popped in a used transmission into my 6cyl 2000 4wd runner that has 250k on it. the transmission is from a 99 limited with about 170k on it. .its got a new fluid and filter in it and has a used torque converter. truck has been solid for the past week or so until tonight.
On my drive home I was going about 65 uphill and decided to jump on it and see how it felt. When i stepped on it hard my rpms dropped down completely and lost power but remained driving up hill. I tried about 3 other times to jump on it and was able to get it to replicate a couple more times on flat road. wondering if anyone has ever had any symptoms like this and if anybody has any suggestions? Truck threw no codes and probably has about 300 miles on it since the transmission was popped in. took about 14 hours so am really hoping the fix doesnt involve dropping that big ***** again. also, truck is on bigger tires (315/75/16)

Are you sure the engine rpms dropping when you dog it has something to do with the replaced trans?

Engine just may need a tune-up yet trans may be just fine. Dig further and let us know.

is there any difference when the ECT PWR button is on?

It would be helpful if you had more specific rpm numbers for before and after applying full throttle.

Maybe shoot a quick video. It's hard to picture what you're trying to describe.

A picture is worth a thousand words, and a video is a *WHOLE LOT* of pictures.

My first thought was it may be fuel related but since I just popped a trans in I figured that was were the problem was. plugs, wires, and fuel filter are all under about 20k miles. gonna drive it around town today and see what else i can come up with.

rpms were prob around 4-5k when I jumped on it to about 1k. engine maintained power just felt like I downshifted or something.

RPMs dropping would be upshifting, not downshifting. Either way, at 65mph, there is no way for the engine to be accelerating the truck and be at 1k RPM. There just isn't a gear that would do that.

Does the engine audibly change RPM, or is it just the tach that changes?

-Charlie

Hey charlie, i'm way off. the truck basically drops from 3k to 1500-2k when i step on it.
it only happens at higher speeds on the freeway. engine noise does seem to change when it drops and truck does seem to bog down.

heres a video from this morning. drives fine when i granny it on the freeway and streets.

https://www.youtube.com/watch?v=9RNfgQhRZwc&feature=youtu.be

Based on what I'm seeing there, the truck is in 3rd gear, then when you floor it, it shifts to 4th and oscillates between locked and unlocked torque converter.

First try driving with OD turned off, which will lock out the trans from 4th gear.

My crazy thought is that you have a bad TPS, which is confusing the ECU as to what gear it should be in...

-Charlie

I'll take it for a spin with the overdrive off later today. It actually did throw a code with the old trans in before the swap for either a tps or maf related code. I can't remember off the top of my head what the code was as I just chalked it up to the bad transmission.

stills happens with ect on

It sounds and looks like a tps issue. What year and trim is your 4Runner?

I second TPS. Especially if you've had a code thrown on the MAF/TPS circuit. its easy to check the TPS if you have a meter. I havent checked it on a 4 runner, but I'm sure a quick search will bring up results.