Hey, i have an '87 4 runner, has about 250,000 miles and i belive im having the start of a trany failure. i go wealing often and my truck is starting to act unusual downshifting or slowing down in second and now third gear.
when downshifting in 2nd of 3rd my truck begins to violantly shake i thought out of tiers out of allignment but if im out of gear it as smoth as silk stoping from the front end it feel to b the steering begins to go nuts. i thought of everythign i could i thought bend my front axel, thought about shot bearing, shattered clutch, broken motor mount but it only happens while in second or third gear downshifting. i get a tiny bit of vibratrion accelerating but as long as i can remember it done that forever but only in 2nd 15- 25 mph. i rebuilt the motor about 50,000 miles ago, i have the 22rec, i have 35 by 12.5, with 5.29 grears and detroit truetrack diffs, 4in skyjacer lift in front and 6" longtravels in the rear. anyother ideas? Do u guys think gearbox too??
thanks for your help

 

Are you having trouble shifting? Does it grind at all?

 

WHats the fluid look like?

 

You have a universal joint going bad. Check it out.

 

That's what it sounds like to me, too.

Usually what starts going bad in the transmissions first is the brass synchronizers with associated problems of shifting gears......coincidentally in the 2nd and 3rd gears. However, those problems can also be related to shifter seat bushing or even the type of gear oil.

 

that or its from a chattering clutch.

all that wheelin will kill your clutch.

 

the fluid looks good changed when i changed my differentials no problems grinding through gears and if my clutch is chatering why doesent it do the same thing downing to my other gears? thanks for the help

 

perhaps the increased torque of downshifting makes it chatter.
50k, and wheelin a lot will kill your clutch.