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93 Cummins trans slips in and out of overdrive #1448561 06/06/13 06:46 PM 06/06/13 06:46 PM
Joined: Jan 2003 Posts: 43,547 Round Lake Beach, Illinoisy Rhinodart OP Rhinotruck
Rhinodart OP Rhinotruck Joined: Jan 2003 Posts: 43,547 Round Lake Beach, Illinoisy	I am in the middle of a banzai run from Chicago to Fort Lauderdale, FL and somewhere in Kentucky the overdrive started to shift in and out. Sometimes it will stay in for 15 or so miles then start shifting again over and over. I am driving it with overdrive off and can only manage about 65 mph and am using too much fuel of course. What caused it and how to fix, any adjustments that can be made on the road? The truck also started idling very low too and will die when coming to a stop but not all the time too. The funny thing about science is that if you change one miniscule parameter you change the entire outcome to the way you want it. JB Rhinehart, Realist A-Body's RULE!

Re: 93 Cummins trans slips in and out of overdrive [Re: Rhinodart] #1448562 06/06/13 07:56 PM 06/06/13 07:56 PM
Joined: Jan 2003 Posts: 4,616 Kissimmee Fl. D dusturbd340W5 master
dusturbd340W5 master D Joined: Jan 2003 Posts: 4,616 Kissimmee Fl.	could be a TPS problem or a OD sol problem VSS problem or internal pressure problem. Would have to put it on a scanner and look at data to see what's going on. 70 duster full chassis super pro 416 CNC Indybrock heads 727 w/brake best so far 1.212 60 6.219 in 1/8 at 110.88 9.768 at 137.81 1/4

Re: 93 Cummins trans slips in and out of overdrive [Re: dusturbd340W5] #1448563 06/06/13 08:04 PM 06/06/13 08:04 PM
Joined: Nov 2004 Posts: 6,653 Near Reading PA USA pinkduster master
pinkduster master Joined: Nov 2004 Posts: 6,653 Near Reading PA USA	Simply unplug it and plug it back in again. This might be a quick "on the road" fix for you and has worked for me MANY times. I assume the slightest bit of green stuff type corrosion can mess up the signal. Sometimes just striking a new connection can clear it up. Sometimes you have to use spray electric parts cleaner and dielectric grease to get it working properly again.

Re: 93 Cummins trans slips in and out of overdrive [Re: pinkduster] #1448564 06/06/13 08:18 PM 06/06/13 08:18 PM
Joined: Nov 2004 Posts: 6,653 Near Reading PA USA pinkduster master
pinkduster master Joined: Nov 2004 Posts: 6,653 Near Reading PA USA	My 93 idles just under 1000 rpm on the factory tach. But a couple years ago it would just randomly fall to about 300 rpm. Never stalled out though. It was the beginning of the end for my injection pump though. Drove it over a year like that. Still ran when I took it in for diagnosis and never did quit on me.

Re: 93 Cummins trans slips in and out of overdrive [Re: pinkduster] #1448565 06/06/13 08:19 PM 06/06/13 08:19 PM
Joined: Nov 2004 Posts: 6,653 Near Reading PA USA pinkduster master
pinkduster master Joined: Nov 2004 Posts: 6,653 Near Reading PA USA	Quote: Simply unplug it and plug it back in again. This might be a quick "on the road" fix for you and has worked for me MANY times. I assume the slightest bit of green stuff type corrosion can mess up the signal. Sometimes just striking a new connection can clear it up. Sometimes you have to use spray electric parts cleaner and dielectric grease to get it working properly again. By "it" I mean the TPS.

Re: 93 Cummins trans slips in and out of overdrive [Re: pinkduster] #1448566 06/06/13 08:28 PM 06/06/13 08:28 PM
Joined: Jan 2003 Posts: 43,547 Round Lake Beach, Illinoisy Rhinodart OP Rhinotruck
Rhinodart OP Rhinotruck Joined: Jan 2003 Posts: 43,547 Round Lake Beach, Illinoisy	I just googled tps and will disconnect it at the next stop and clean the connectors, thanks! I have a Chivvy electric pump now and it works flawlessly and only cost $90 and you can get one at any parts store, so no more Dodge pumps for me... The funny thing about science is that if you change one miniscule parameter you change the entire outcome to the way you want it. JB Rhinehart, Realist A-Body's RULE!

Re: 93 Cummins trans slips in and out of overdrive [Re: Rhinodart] #1448567 06/06/13 10:27 PM 06/06/13 10:27 PM
Joined: Jan 2006 Posts: 452 Coeur d Alene, Idaho J jimbob101 mopar
jimbob101 mopar J Joined: Jan 2006 Posts: 452 Coeur d Alene, Idaho	Does your speedo work? Sometimes unplugging and checking out the two wire connector on the trans or transfer case has a bad connection. THe speedo is part of the OD shift, and also the trans temp sending unit on the front trans line coming out of the trans. Could be a worn out TPS unit that sits on the top of the injector pump. All the auto trucks I've had, have had to replace them sooner or later. But kinda weird that it happened in a middle of a trip!

Re: 93 Cummins trans slips in and out of overdrive [Re: jimbob101] #1448568 06/07/13 06:55 PM 06/07/13 06:55 PM
Joined: Jan 2003 Posts: 43,547 Round Lake Beach, Illinoisy Rhinodart OP Rhinotruck
Rhinodart OP Rhinotruck Joined: Jan 2003 Posts: 43,547 Round Lake Beach, Illinoisy	Stopped for dinner at the Crackhead Barrel and unhooked the connector to the TPS three times. Just got back from the last 1,000 miles and the overdrive worked flawlessly! If only I would have checked here for the first 2,000 miles... My right foot was cramped-up good trying to get 65 MPH out of the truck with no OD. The funny thing about science is that if you change one miniscule parameter you change the entire outcome to the way you want it. JB Rhinehart, Realist A-Body's RULE!

Re: 93 Cummins trans slips in and out of overdrive [Re: Rhinodart] #1448569 06/07/13 09:03 PM 06/07/13 09:03 PM
Joined: Nov 2004 Posts: 6,653 Near Reading PA USA pinkduster master
pinkduster master Joined: Nov 2004 Posts: 6,653 Near Reading PA USA	Quote: Stopped for dinner at the Crackhead Barrel and unhooked the connector to the TPS three times. Just got back from the last 1,000 miles and the overdrive worked flawlessly! If only I would have checked here for the first 2,000 miles... My right foot was cramped-up good trying to get 65 MPH out of the truck with no OD. Nice! 65 mph out of one of these trucks without OD is nuts! It must have been screamin'. Your nerves must be shot! I can't stand driving mine without OD. If it starts to act up, I pull over IMMEDIATELY and unplug it and plug it back in.

Re: 93 Cummins trans slips in and out of overdrive [Re: pinkduster] #1448570 06/07/13 09:34 PM 06/07/13 09:34 PM
Joined: Oct 2003 Posts: 2,537 PORT ALBERNI , BC., CANADA superwrench master
superwrench master Joined: Oct 2003 Posts: 2,537 PORT ALBERNI , BC., CANADA	Yep...I got 4.10's in my 92....55 MPH is MAX without OD.....changed that TPS a few times along with the speed sensor on the trans. I keep spares now if on a long trip. Only bad thing is that the TPS is STUPID expensive (500.00) up here.I've tried the connection thing at the plug, but it was only a bandaid fix...screwed up a week later.My vote is put a NEW TPS in there...and NOT one from an auto parts store....get the Chrysler one.

Re: 93 Cummins trans slips in and out of overdrive [Re: superwrench] #1448571 06/07/13 09:52 PM 06/07/13 09:52 PM
Joined: Nov 2004 Posts: 6,653 Near Reading PA USA pinkduster master
pinkduster master Joined: Nov 2004 Posts: 6,653 Near Reading PA USA	I had my TPS replaced back in 2002. It wasn't anywhere near $500 (from the Dodge dealer). For the past 11 years, I've had to do the unplug thing maybe twice a year. The last time it happened, I sprayed both connections out with electric cleaner and I absolutely loaded the inside and outside of the plug with dielectric grease and it has not happened since. I think , for me, it has all been about keeping moisture out of the connection. Last summer, the speed sensor did crap-out again. I've replaced that twice in the 12 years I've owned the truck. Keeping a spare in the glove box is probably a good idea.

Re: 93 Cummins trans slips in and out of overdrive [Re: pinkduster] #1448572 06/07/13 10:32 PM 06/07/13 10:32 PM
Joined: Jan 2003 Posts: 43,547 Round Lake Beach, Illinoisy Rhinodart OP Rhinotruck
Rhinodart OP Rhinotruck Joined: Jan 2003 Posts: 43,547 Round Lake Beach, Illinoisy	I read all about replacing the TPS with a potentiometer, but there are equal yes's and no's, what have you guys heard? The funny thing about science is that if you change one miniscule parameter you change the entire outcome to the way you want it. JB Rhinehart, Realist A-Body's RULE!

Re: 93 Cummins trans slips in and out of overdrive [Re: Rhinodart] #1448573 06/08/13 02:01 AM 06/08/13 02:01 AM
Joined: Jan 2003 Posts: 12,043 State of Confusion hp383 Just a normal tag again
hp383 Just a normal tag again Joined: Jan 2003 Posts: 12,043 State of Confusion	My 93 had the potentiometer conversion done. I liked it, never had any trouble with it. I also liked having the ability to sdjust when the OD would engage. If you do the swap, just remember a tiny adjustment on the know is all you need to move the OD engage speed. No need to do any real cranking of the dial. Also as mentioned keep an eye on the VSS, and the plug in connector. These too will cause you to lose OD, but usually the speedo will either not register, or will bounce around if this is the problem. My 93 went through 2 new VSS units in as many years. Join the Penguin Liberation Front!! Stop the Hippo Occupation!

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