Hello,
I have a 1995 4runner. v-6 auto. When I am driving, the tranny, when in lock up, will start to slip alittle. not always alot but if will jerk and slip ever so slightly. then when i am doing about 55-60 and about 3,000 rpms, not lock up, the rpms will start to waiver in a range of about 200-500 rpms. Is it the transmision filter? If it is, what does it take to replace/ clean?

Thanks,
Joe

 

Well my take on this is......

I dont think it sounds like a transmission problem at all. I get the impression your are experiencing a "surge" from the engine. Sounds like a common conern I hear alot. Here in Oregon, (not sure this a location problem, our gas sucks), I see alot of poor flowing fuel injectors.

Corey posted a Injector flow test sheet of his repair. Click HERE .

This shows the before and after readings of the flow volume. Poor injector performance can create that "200-250 rpm fluctuation" you described at specific RPM's.

A Power Balance test can be performed to test each cylinders performance, using an Scope. This test measures the rpm of the engine running normally ( BASE ), then cuts out each cylinder in turn and measures rpm with each cylinder cut. A weak cylinder is spotted by the cylinder cut rpm compared to the BASE. If with cylinder #2 cut out, the rpm is close to the BASE, then you would summize that there is a problem in that cylinder.


Hope this information helps

Jay

 

Hey! Welcome to the forums!

I've got a dumb question: by saying your tranny is locked up does that mean that it is not in overdrive? My tranny does the same thing after I've been driving for a while when I'm in overdrive. I'm not sure if it does it or not while overdrive is off. I don't usually drive with my overdrive off. While in overdrive on my 4runner, the RPMs will fluctuate by about 400RPM several times. It'll only last about 10 minutes and is fine for a while more. Something is wrong with it, but I dunno what. I reckon its time to have it checked. I was under the impression that the direct drive clutch or whatever (sorry not sure what this is called) in my torque converter was disengaging and engaging a bunch of times while driving around 55. I dunno. What Jay says make sense too. I hadn’t even though about bad injectors.

I would try to answer your question about how to change the fluid, but it has been so long, I don't want to give you any wrong info. I do know that the dipstick tub disconnects about 16 inches up from the tranny. We learned this the hard way. We were trying to remove the WHOLE dipstick tube. What a pain. We took out all the air cleaner assembly and several brackets off the exhaust heat shield (I guess that's what it is). Later we found out that the tub disconnects. So you don't have to remove the dipstick tube in the engine bay. You may have to unscrew the u bolts holding up the front sway bar (I think that's what it is called) to be able to drop the transmission pan. If I remember correctly, there are several more screws holding up the filter. I don't know if your truck is 2wd or not, but make sure you get the right filter for your configuration.

Well, sorry for rambling on. I'm not sure if I was of help with my limited experience on this, but oh well. I'm tired and it was worth a shot.

Anways, welcome to the forum.
Have fun.
DH6twinotter

 

Torque Convertor in an Auto Trans, is what replaces the Clutch of the Manual Trans. However, the Torque Convertor will always slip if it is not for the "Lock-Up" Clutch it has inside of it. When the computer determines the vehicle is remaining at a constant speed, it locks this "Lock-up" clutch to conserve fuel. Creating a 1:1 ratio between the engine and the input shaft of the transmission. At some point during acceleration, the computer disengages this clutch to allow the torque convertor to "slip" to help make torque.

Carefully studing the tacometer while driving, you can watch the vehicle shift from 1st to 2nd, 2nd to 3rd, 3rd to OD, and then OD to Lock Up. Or from 3rd to Lock Up w/ OD switch off. However only a small rpm drop is noticed while shifting into Lock Up.

Just some basic information of the topic for ya.

Jay

 

When looking for the RPM drop upon reaching Lock-Up mode, watch the tach at precisly 48mph when you are in OD and 46 when you are in 3rd gear. Also I notice that the trans will unlock in 4th at 44mph and in 3rd at 42mph.

I hear that the 4th gen V-8 5-speed auto trans has some sort of variable lock-up type TQ. Anyone know any more info on this...sounds very interesting.