Keith Browning Posted July 14, 2005 Share Posted July 14, 2005 Anyone good with automatic transmissions? 4R100 Locks-up in Reverse when hot but intermittently. I know that I am filling three drums with reverse applied. I have good pressure but I need to check flow before I start turning bolts. My question to my fellow Dr's is, how would a torque converter clutch lock with low pressure or volume without energizing the TCC solenoid? I have no training in transmissions which probably explains my confusion. Is the torque converter clutch actually UN-APPLIED when it is not engaged during operation? /forums/images/%%GRAEMLIN_URL%%/confused.gif ( is it actually applied at rest when the truck is shut off? ) Quote Link to comment Share on other sites More sharing options...
FordTechCA Posted July 14, 2005 Share Posted July 14, 2005 what year is it? is it stalling the engine? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 14, 2005 Author Share Posted July 14, 2005 It's an 02 7.3L with a 4R100 that when hot, will really bog down and almost stall in reverse, for me. The customer has stated that it has stalled on him and it's getting worse. I called the HotLine and I got the usual response about filters and fluid. Nope. We changed them and I also checked pressures and flow - right on the money! I wish has asked this question while I was on the phone with them. The trans is coming out tomorrow and I will take a good look at the pump and stator support seal. One thing I noticed was while doing the WOT pressure test in reverse, it would start to act up and my pressure would drop from 255 PSI to 180 PSI, and immediately after doing that the pressure at idle became erratic and then evened out. Personally, I think there is something amiss in the pump/converter area. All other shifts and engagements are fine. Quote Link to comment Share on other sites More sharing options...
Kyle E. Grathwol Posted August 14, 2005 Share Posted August 14, 2005 If it is only reverse you may want to look for distortion in the valve body area. Where the center support bolts go through the case. Put a straight edge across that area before you loosen the bolts. There are aftermarket spacers to put in between the case and CS along with thicker VB gaskets. There is also a jig available to push the case back into specs. I had the same problem and when I overhauled the trans, that's all I could find. The spacers solved the problem. Worn pump and gears will do the same thing but in drive and reverse. Good Luck. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted August 14, 2005 Author Share Posted August 14, 2005 Thanx for the reply, I should have followed up on this one because I did fix it. A new pump and converter did the trick. It helped to know that in reverse and drive (1st) you have the most number of clutches applied. When this unit got hot it started to lose pressure just enough. I am sure that if allowed to progress it would have caused it to lock up in drive. They always seem to start doing this in reverse it seems. I still haven't figured out how low pressure causes the converter to lock up though /forums/images/%%GRAEMLIN_URL%%/confused.gif Quote Link to comment Share on other sites More sharing options...
Kyle E. Grathwol Posted August 15, 2005 Share Posted August 15, 2005 Worn pump gears allow oil to by-pass the pump and fill the converter housing not letting oil out of the back side of the TCC. This also causes a drop in pressure. If you give me your fax no. I can fax you info on it. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted August 15, 2005 Author Share Posted August 15, 2005 Ahhhh haaaa! This must be what they mean by the term "cross flow" in the pump. /forums/images/%%GRAEMLIN_URL%%/notworthy.gif Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.