DanW Posted April 20, 2007 Share Posted April 20, 2007 Lately, my '92 LS400 has been shift hard after the trans warms up. The fluid is nice and red, filled to correct level...its never really had any problems. I don't know when the filter was changed if ever...just past 190K miles now. When cold the thing shifts smooth as silk. After running about 5 minutes it starts to get pretty rough, sometimes 'thuds' into gears. Mostly on upshifts, downshifts are usually pretty smooth. Doesn't slip, doesn't grind, none of that stuff. Just shifts substantially harder when hot. Has anyone else experienced these symptoms? I wonder if its not those infamous solenoids showing their age... Quote Link to comment Share on other sites More sharing options...
DanW Posted April 20, 2007 Author Share Posted April 20, 2007 Lately, my '92 LS400 has been shift hard after the trans warms up. The fluid is nice and red, filled to correct level...its never really had any problems. I don't know when the filter was changed if ever...just past 190K miles now. When cold the thing shifts smooth as silk. After running about 5 minutes it starts to get pretty rough, sometimes 'thuds' into gears. Mostly on upshifts, downshifts are usually pretty smooth. Doesn't slip, doesn't grind, none of that stuff. Just shifts substantially harder when hot. Has anyone else experienced these symptoms? I wonder if its not those infamous solenoids showing their age... Forgot to also mention, it does get into evey gear ok. The only other thread I was able to find had to do with 'losing' gears when the trans got hot. Mine just shifts hard. Are the solenoids or anything else ever known to get 'sticky' in these transmissions? Quote Link to comment Share on other sites More sharing options...
DanW Posted April 26, 2007 Author Share Posted April 26, 2007 Looks like it is one of the solenoids crapping out. Anyone have a good source on new ones? May as well just change both... Quote Link to comment Share on other sites More sharing options...
LScott400 Posted April 26, 2007 Share Posted April 26, 2007 I think you're looking at dealer parts. Quote Link to comment Share on other sites More sharing options...
nc211 Posted April 27, 2007 Share Posted April 27, 2007 DanW, when I bought my 95, it was doing the same thing, especially when the a/c was running. I took it back to the dealership for a fix, and they adjusted the slack in the throttle cable. There is a seperate tranny computer that is attached to the cable plate on the engine. In shade-tree talk; on the passenger side of the engine, on the top, towards the firewall, you should see the cable plate, where your throttle cable connects to the throttle body. You'll also see another cable with a tightening bolt on it, that is the one to the tranny computer. If you just back that bolt off a turn or two, it should put a little more slack in that line. What happens is that over time the slack in that line tightens up, which can trick the tranny computer into thinking you've got your foot mashed down on the gas. It basically makes the tranny think your going faster and harder than you really are, which makes the computer shift gears faster/harder. Not saying the solenoid isn't worn out, but try the slack adjust first, might save you a few bucks and hassles. I know it fixed mine back in the day. I need to readjust it again now since I've scrubbed the throttle plate and intake clean, seafoamed the intake a few times and put new plugs in the engine. I've noticed the more I do to rehab the engine's performance, the hard it shifts. Just gotta' put in a little more slack, or take some out, don't know yet. My tranny fluid is spotless too, drain n' fill every oil change. Quote Link to comment Share on other sites More sharing options...
DanW Posted April 28, 2007 Author Share Posted April 28, 2007 DanW, when I bought my 95, it was doing the same thing, especially when the a/c was running. I took it back to the dealership for a fix, and they adjusted the slack in the throttle cable. There is a seperate tranny computer that is attached to the cable plate on the engine. In shade-tree talk; on the passenger side of the engine, on the top, towards the firewall, you should see the cable plate, where your throttle cable connects to the throttle body. You'll also see another cable with a tightening bolt on it, that is the one to the tranny computer. If you just back that bolt off a turn or two, it should put a little more slack in that line. What happens is that over time the slack in that line tightens up, which can trick the tranny computer into thinking you've got your foot mashed down on the gas. It basically makes the tranny think your going faster and harder than you really are, which makes the computer shift gears faster/harder. Not saying the solenoid isn't worn out, but try the slack adjust first, might save you a few bucks and hassles. I know it fixed mine back in the day. I need to readjust it again now since I've scrubbed the throttle plate and intake clean, seafoamed the intake a few times and put new plugs in the engine. I've noticed the more I do to rehab the engine's performance, the hard it shifts. Just gotta' put in a little more slack, or take some out, don't know yet. My tranny fluid is spotless too, drain n' fill every oil change. I'd heard about that adjustment but wasnt sure how to do it...thanks for explaining it. I tried it today and it definetely made a difference. The hard shift problem was intermittent, so I'll drive it for a while and see if it comes back. Everyone I have talked to thinks it is a solenoid, acting up and sensitive to.....something....who knows. Maybe it was that cable...sensitive to...something...who knows. It only happened hot some maybe when that cable got hot it got tight in the jacket. Who knows...most cars don't last this long so we run into lots of unique issues. Thanks for the advice. Quote Link to comment Share on other sites More sharing options...
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