Transmisson hunting at 45mph
 

I read a lot of post about how to fix this problem and I may have found a way to fix part of this problem, at least on my truck.

My truck(1998 with 24V) recently quit charging. After checking the alt(new one last year) and for fusible links(none bad). I started tracing wires. I found the problem to be a broken wire that comes from the alt. to the fuse box on the left side of the truck. This is a heavy black wire that runs through the loom with a lot of other wires. I might have pinched it while changing the left front shock. I had NAPA make me a new one(six feet I think) and ran it from the alt to the fuse box. I zipped tied it to the outside of the wire loom. After replacing this wire I have not issues with the transmission hunting for the right gear around 45mph. I read that the noise coming from the wires sometimes causes the trans. to do strange things. Not saying this will fix your problem but it fixed mine for less then $20 bucks. Happy Thanksgiving. Phil :cool:

Good post. Also clean, tight battery terminal connections are critical for proper shifting. I also had hunting in this speed range and was going to put in the noise filter but heard about cleaning my battery terminals. I thought they were fine but they were corroded and loose. Cleaned and tightened and all was good.

........An oldtimer 1ce told me to run a ground strap/cable from the tranny to the frame......kim.........

trans hunting
 

my 98 did the same thing,l tried changing the TPS swith of my other 98,that didnt work,l went to a trans shop and the guy was excellent to deal with as he said to go to the dodge dealer ship and get them to punch in 99 codes,l ask them to do that but they were reluctant,after they did it has never missed a beat?

You can dot your I's and cross your T's and it will probably still hunt. Honestly do a search / check out Geno's garage and look at the 30$ wire splice that grounds the ECM (I think). From research I have done this is the one thing that cheaply corrects the surge without tin foil, rerouting wires, giving batteries pedicures, and placing isolators on everything. If it continues to surge there is probably a mechanical problem some where that will require trouble shooting and repair. There are some diagrams that I have that also ground the ECM that are supposed to fix the problem. But, cutting wires, rerouting them, and then reconnecting them when I do not know exactly what does what, is kinda risky. Good luck man, but check out the wire adapter / ground, you'll hear a lot of people blogging about it and it is cheap and easy.

2-years ago, my 2000, 24V Cummins w/ auto tranny did the same; that is continuously shifting in/out of overdrive at speeds of 45-50 mph. i got lucky in finding a good mechanic and the problem turns out to be fluctuating voltages with the alternator. He told me "you won't believe me". So I listened and was skeptical. After encountering a "check instrument" light indicator, I opted to replace the alternator. Got lucky as the tranny problem disappeared. It turns out that with an unstable voltage, it causes the "cycling" of constant shifting into/out of overdrive.
For a year since replacing the alternator, no further problems were noted until a couple of months ago. the problem started up again and he enlarged the small diameter hole that allows tranny fluid to engage the overdrive. with a larger diameter hole, it allows for more fluid pressure (thus force) to engage the overdrive and stop the "cycling" problem. He has applied this fix on several other trannys with no further problems. Transmission repair is his specialty and he does very good work.

hope this helps.

install a torque convertor lock up switch

Let's start with the free fix. Clean all of your grounding points.

There are 6 total. Clean both negative battery terminals. There's also two wires going from the negative terminals to the chassis. Clean the terminal end on the wire and the chassis point. The crucial one is the PCM ground. The PCM is on the firewall, passenger side. Clean both end of the ground wire and the connection points. I replaced my PCM ground wire due to the amount of corrosion I saw.

That should take care of it. In most cases the hunting is caused by a "ground loop". Those are caused by dirty and corroded ground connections, which puts noise and stray signals in your electrical system. And since overdrive is electrically controlled, it gets affected. Hope this helps.

there is no one cure fixes all. Bad batteries, bad alternator, bad wiring are VERY HIGH probabilities. Test all off vehicle. Bad connections can be anywhere. Battery cables corroded/loose and any other connection should be inspected. Alt wiring and two gray connectors to right side battery are starters.
You don't need a band aid to fix a problem. All the add on bandaids cause a improper downshift issue. These trucks did not exibit condition for 5-12 years of service and don't need junk added to them. Find and fix the problem by getting hands dirty.

I followed jrs dodge diesel's advice and that fixed mine. Can't beat the help here. :thanks:

You're welcome :)

tin foil work for me.

from guy1996 i reqd about a lot of fixes for hunting trans and tried several but none worked but one that was a new ground wire from apps that did correct problem for appros six mo. then problem returned. i then installed the apps noise isolator from genosgrage 23.75 and have not had a problem since . genosgarage 1.800.755.1715