C4 question

So the trans we pulled out of my brothers 75 grabber has been sitting in my garage and I'm thinking about throwing it in my 64 falcon. It has a problem and that's why we pulled it out. I believe it is in the valve body and just wanted a second option. It is not slipping. When you stop and start to go again you have to rev the engine up and it kinda slams into gear and then it shifts fine. I think one of the spools are sticking. I'm going to pull it apart and clean them. Is there anything else I should check. I've rebuilt c4's before so I'm not afraid to get into it I just really don't want to tear it down right now. It has around 89,000 miles on it.

 

I've seen loose valve body bolts cause same, also loose pump to case bolts...

 

Ok I'll make sure I check them.....

 

If your taking the tranny out of the car check the end play and make sure it is within spec, this is a critical thing in an automatic that home builders some times over look! When I pulled a C5 out of my Ranger it had 0.070' more than it is supposed to have!

 

Check the 2-3 Servo - it can stick or the rubber on the piston is allowing leakage around it.
Check the modulator valve - rubber hose at the modulator or at the engine intake manifold. Also, the diaphragm inside the modulator could be leaking.

 

Make sure you have good vacuum to the modulator on the tranny. Make sure your fluid is full while the car is running in park .

 

So I started by pulling the valve body off and decided to pull it down. The trans fluid wasn't changed much and it was full of varnished fluid. So I'm doing a full rebuild now.

 

Deciding to pull it and rebuild is the right decision, that way you'll know it's right. Good time to add a shift kit.

 

Yeah I was hoping that didn't have to dive too deep into the trans but after I pulled the valve body I decided it was way too dirty. Some of the thrust washers had way too much wear so I ordered aa thrust washer kit yesterday. I'll grab a rebuild kit from O'reilly and be good to go. The funny thing was all the hard parts exept the clutches the one band and the thrust washers were in great shape.

 

Your initial diagnosis of a sticking spool was probably right.

 

Good call! That is most likely the case Auto tranys don't like any kind of grindings

 

Yeah I've rebuilt a few auto trans and never had a problem with any of the rebuilds. I have found if you take you time, replace worn parts, and make sure everything is clean you will have good results. I guess it helps I repair industrial hydraulics for a living.