86 caprice, 307, 200R4, 2.53:1 (if memory serves) gears. fluid looks and smells normal. i was driving it tonight and it seemed like the trans was slipping in and out of 4th. also i had to keep it floored on a slight uphill just to maintain freeway speeds. also about 55 or so it was shifting in and out of 4th with very light throttle. idea?? i cant afford to have this beasty go down right now untill i get my Marquis, Passat, or Sundance going right.
I have an idea but I'm not sure it applies to the 86. I don't have lots of Chevy experience but it seems to me that there an electronic thingy that controls the overdrive and when they go bad you get that in/out of overdrive a lot. It can't make up it's mind. I've heard mention somewhere that to troubleshoot there's a plug you can just disconnect. It will eliminate that problem but will also allow you to see how it drives with just three gears. If it drives normal with three the part is about $30 to replace. You need a friend with a tranny book that covers the GM four speed automatics.
i know a guy thats good with transmissions, might take it over to him when i have some more $$. thanks!!!
Not being a newer GM guy, I can't offer any ideas for a solution, but this might be of some value: http://mmerlinn.com/catalog/makeridx.htm Your trans is here: http://mmerlinn.com/catalog/flurosenia/gm_720/gm720_f.htm#default http://www.makcotransmissionparts.com/mm5/merchant.mvc Might have to seek out a Chevy/GM site like V8Buick.com or ImpallaSS?
Sounds like a 4th gear (OD) lock up problem to me. Could be the switch. Could be the torque converter. Could be several things. Have your tranny guy test it out to isolate the problem. I could give you 5 causes but it would be best to just find it. You don't say how many miles are on that 200-4R. They are a tougher tranny than most people realize so lets hope it's one of the simpler fixes.
i have no idea how many miles are on it. i do know that it was replaced with a Jasper unit before i bought it but i am not sure how long before, ya know??. i do knwo its less than 200,000 as the car has 219,000 on it currently.