Hey, everyone,

I've got an '86 4Runner with the 22RE. It is an automatic. It has about 80,000 original miles on it.

I've got a couple of questions:

For the longest time, it's had a problem when accelerating smoothly, when engaging 3rd gear around 25 - 30 mph. Recently, the problem has gotten a bit worse, and I wanted to tackle it before it became something serious!

The problem is pretty well that at 25-30 mph, the transmission will shift around say 2100 - 2200 rpms on the tach, and the whole vehicle will get a noticeable shake / shudder as the next gear is engaging. Once in 4th gear, everything is back to normal, and nothing is amiss. You don't get a shudder when slowing down at all, either. You do get about the same sudden shake / shudder feeling when engaging reverse gear (obviously from a stop), however.

While shifting in the other gears probably isn't as crisp as I'd like it to be, it's acceptable, and nothing like the 3rd - 4th gear shift.

The tranny fluid has been replaced every 3 or so years, and the vehicle was never driven much, so it wasn't really replaced based on mileage. The tranny fluid level is within the acceptable range, looks fine, and doesn't smell burnt.

I'm planning on switching the fluid over to Amsoil Synthetic fluid in May or so, and doing a complete fluid changeover (the 12 or so quarts), as all that has ever been done on the vehicle is the simple drain + refill. I will drop the pan, check the filter, and completely replace the fluid from the pan and torque converter. I know this is not supposed to cure a problem like I'm having, but I thought it was worth mentioning.

If any of you have encountered such a problem, let me know how you fixed it -- I'd like to have some input before I go tearing into my transmission!