4+3 jumping out of Overdrive Randomly
05-08-2018, 11:45 PM
#1
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Thread Starter
4+3 jumping out of Overdrive Randomly
My 4+3 Transmission worked great until something has started to happen. I'll randomly be driving down the road, usually during highway speeds 70 - 75mph and the car will jump in and out of overdrive. It's as if someone were flipping the overdrive switch off and on. It'll stop and then the car will drive normally again.
It happened twice on a recent trip to New Jersey, a 400 mile round trip. Once on the way down, and once on the way back.
Today on another trip to Ithica, it threw a much worse temper tantrum. For about a minute it'd randomly kick out of Overdrive and then go back into it, when it happens I push in the clutch and turn it off and then drive further and try again. Eventually it goes away, the car drives about 100 miles on the highway home and it doesn't happen again.
The fluid was changed in the OD unit about 1000 miles prior to the trips. From what I understand about these devices, and based on what I've read on the forums it's either the relay or the relay wiring harness/connection?
Does that sound right? I have had the mod done where it makes the overdrive manual.
It happened twice on a recent trip to New Jersey, a 400 mile round trip. Once on the way down, and once on the way back.
Today on another trip to Ithica, it threw a much worse temper tantrum. For about a minute it'd randomly kick out of Overdrive and then go back into it, when it happens I push in the clutch and turn it off and then drive further and try again. Eventually it goes away, the car drives about 100 miles on the highway home and it doesn't happen again.
The fluid was changed in the OD unit about 1000 miles prior to the trips. From what I understand about these devices, and based on what I've read on the forums it's either the relay or the relay wiring harness/connection?
Does that sound right? I have had the mod done where it makes the overdrive manual.
05-09-2018, 04:06 AM
#2
Burning Brakes
I had a bad throttle position sensor on my 1985 that caused the overdrive to kick out randomly. The ECM thought I was flooring the gas pedal and was turning the overdrive off (as it should). Once I replaced the TPS, the overdrive worked great again.
The following 2 users liked this post by LWesthaver:
flannel_man (05-09-2018),
Steven Haffley (05-09-2018)
The following users liked this post:
Steven Haffley (05-09-2018)
05-09-2018, 12:19 PM
#4
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Thread Starter
Do you have the same one as me? I have the early 85 where it's a flip switch on the center console, when this started happening i'd wiggle it around to see if it made a difference but it didn't seem to have any effect on it.
05-10-2018, 05:36 AM
#6
Instructor
I never would have thought this may cause this, maybe this is what is going on I'll have to check this as well.
Do you have the same one as me? I have the early 85 where it's a flip switch on the center console, when this started happening i'd wiggle it around to see if it made a difference but it didn't seem to have any effect on it.
Do you have the same one as me? I have the early 85 where it's a flip switch on the center console, when this started happening i'd wiggle it around to see if it made a difference but it didn't seem to have any effect on it.