tb

Hi there,

I've got a 1990 4 runner, 3.0, 400k, manual tranny. Bought the truck with a blown motor and put a new one in. Was told the truck had a replaced transmission.

Got the truck going but the issue is that the clutch won't fully disengage. It is very difficult to put truck into gear and it grinds putting it into reverse.

I've replaced the master and slave cyl and bled it many times. I also adjusted the top out screw (?) for the clutch pedal to get the longest stroke possible for the master. (this seemed to help slightly but didn't fix the problem)

I didn't check the throw out bearing when I had the other motor out, could it possibly be that? Bent clutch fork?

Anyone else have this problem or any ideas? Just trying to look for other ideas before I pull the transmission. Thanks

Tyson

muddpigg

iTrader: (1)

Did you inspect the clutch plate?

tb

Yep, I took out the clutch/pressure plate and inspected everything. I didn't resurface the flywheel but I don't think It should have been much of an issue. There weren't any heat spots and i used a scotch bright pad on both the flywheel and pressure plate. This obviously isn't ideal but I was trying to do everything as cheap as possible. The clutch doesn't chatter or slip and grabs hard.

muddpigg

iTrader: (1)

I ment measure the amount of friction matterial on the clutch.

The shaft that attaches to the pedal is threaded. It may not be adjusted enough so that the shaft allows the plunge to go to full travel when the pedal is all the way out.

tried4x2signN

oh gosh... I'd never adjust the pedal of a hydraulic clutch...

muddpigg

iTrader: (1)

you would if you ever replaced a slave cyclinder or master cyclinder of the brakes.

tried4x2signN

No on the slave, and yes to the master to match the mount on the threaded adjuster just prior to installing it...


Otherwise, hydro clutches are not to be adjusted. That's something you do to the old linkage type clutch forks...


If you're clutch is slipping it's time for another one. Not an adjustment so you can run it past the rivets.

xxxtreme22r

I had to adjust my pedal when I put the new clutch in mine after a rebuild. 1st and reverse would not go in without grinding till I did.

tb

Ah gotcha, sorry about that. I see what you're getting at. The clutch was from a truck which didn't have any sort of shifting issues. I didn't actually get a caliper on the clutch disk but it looked fine from a visual perspective. I'll definitely get a measurement if I pull the tranny.

As for the linkage adjustment, it definitely affects the stroke of the piston on the master. It sure made a difference when I adjusted the pedal position.

JJ'89

On my '89 22re 5-spd 2wd pickup, the clutch pedal bracket was cracked and flexing severely causing difficulty shifting and popping out of gear. New bracket installed fixed it right up, also bushings in top of the trans case were shot too.

tb

I'll definitely take a look at that tomorrow. Thanks

muddpigg

iTrader: (1)

See the threaded rod that goes through the firewall. Yep the threads are for adjusting:-).

If you simply counted threads may not actually give you the result you'd think. I replaced mine not long ago and had to actually trim the rod back as it was hitting the pedal. Yep, my clutch would not fully disengage.

BrutalIntegrity

sounds like you need to adjust the pedal free play

fork

so THATS why i have trouble getting it into first! learn something new every day. one more thing to attack. i love YT

tb

I forgot to mention I did this as well. I've pretty well lengthened stroke as far as it as far as it can go (screwed in about 3-4 or so threads) and even though this made the largest improvement, reverse still grinds most of the time.

Just to clarify for everyone if i'm not sounding clear: the stroke of the master cylinder piston is adjusted to the longest it could possibly be and it still will not fully disengage the clutch. (only in reverse though, all other gears seem to shift more smoothly than before).

Just from reading most of what I've written and thinking about this a little it would it be unreasonable to think that there could be some sort of issue with the transmission if I'm only having this problem with reverse?

Feel free to correct me if you don't think I'm on the right track here.

Thanks a lot for the help guys.

DaddyRunner

Reverse has no cyncros try shifting into first before reverse it will help until you get the problem fixed. All my toy's would grind a little going into reverse now I'm just in the habbit slipping it into first gear real quick while the clutch is in and then to reverse it lines up the tranny and goes right in.

muddpigg

iTrader: (1)

I think you are missing something.

That adjustment if the length is to long the clutch will not disengage. Too short and in won't fully engage.

vital22re

iTrader: (2)

... reverse grinds in a lot of these older transmissions. How are your shifter bushings? fluid level/condition of the transmission?

tb

I must not be explaining this correctly

The longer the stroke of the master piston = the longer the travel of the slave cylinder piston

The position of the clutch pedal won't affect the initial position of the slave cylinder piston provided the clutch is bled following the adjustment of the pedal. This means that the only thing affecting the travel of the slave (which will determine when the clutch disengages/engages) is the amount of travel of the master cyl piston.

I know thats not really the best explanation, but I'm quite sure this is what is going on.

tb

I think this is most likely the best explanation. Shifter bushing is fine, but I haven't checked / changed the fluid. I'll definitely try this today. Thanks