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Discussion Starter #1
We have a 91 Cummins extra cab, 4 x4, automatic.

The tranny keeps going out. What transmission did this come with? Anything to do to beef it up? Source for a built tranny? Going on our fourth and we would like more than a stock one. We use this rig for towing a lot.

Thanks
 

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An auto trans of any make or type has 2 main enemies: excessive heat and clogged filters. I would guess your truck has a 727 Torqueflite 3spd without overdrive. You should get the biggest tranny cooler you can lay your hands on, like the big B&M unit. Plumb it in correctly too. Change fluid and filters at the very least once a year, twice a year for frequent heavy towing. Always shift the tranny into neutral when stopped, even at a light, to let fluid circulate better. Install a tranny temp gauge to monitor what you're doing to it and let it cool off when temps start getting up there. An aftermarket Hi-po torque converter is strongy suggested for towing.

That may not be unusual to have 4 rebuilds depending on the number of miles and amount of abuse between rebuilds. Could be you need to find a different tranny shop too!?? Sounds excessive. Fella was just complaining to me about the $3,000 rebuild on his Torqueflite A1518 equipped Cummins. Said it was now kicking out of overdrive again. I explained that it was probably the throttle position sensor or the overdrive switch causing the problem. He took it back to the same shop: overdrive switch was replaced. Finally fixed what was his original problem, $3000 later and no refund on the ripoff rebuild!
 

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You might ad the auxiliary transmission water cooler that mounts under the bed but first check your current water cooler for corrosion. If your truck is an early 91 it does not have a factory supplied intercooler it normally comes with the 727 non overdrive transmission. If that is the case and top speed isn't a priority you could swap out the rears to 3.54's which would remove some of the load off the transmission. That would put you around 2100 RPM's at 55 MPH running stock size tires. Then send those 3.07 rears to me ha ha! :D Also If it has the intercooler and an overdrive transmission just don't tow in overdrive.
 

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If you have been taking it to the same builder you need to stop doing that. What exactly has been wrong with it is my next question? Did someone disconnect the water heat exchanger tranny cooler? Did someone put a gasoline engine tranny pan on it (less fluid capacity)? Does it have the underbed air to air auxiliary cooler? And do you have a transmission temperature gauge on the pressure out cooler line? The 727 three spd. from the factory had an inefficient torque converter, 60% ish efficient, they created a lot of heat, heat is the number one factor in killing the transmission, most people have no idea what the gauge importance is. Keep those 3.07's and treat them like a nice old lady only better. Get them serviced ASAP or plan on a pair of axles (front & rear) because they are obsolete now. I would like to hear more on your trans before I ramble anymore...

Best Regards, Ross Marcotte ;)
 

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trannie

I have a 2000 with auto 277.000 miles pull all the time ,Only 1 rebuild I used all dtt trans stuff.I can honestly say that it was the best thing i have done to my truck,shifts great no slipping or any trana problems since i did it.
Pat
 

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First off you need to find out what went wrong or what cause it to go out.

1. Most of the time it's geeting hot ,and burning up the clutches.
2. The cooler has a lot to do with it. * spend the $300.00 and get a remote cooler with a fan and mount it away from any heat.
3. The last thing is stay away from or trans guy if he has touched all 4 trans.


If you want a auto trans to last talk to Dave Goerend AKA Goerand Brothers

He builds the best auto trans !!!!!!
 

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Discussion Starter #7
Thanks for all the info guys.

The truck does have an intercooler and does have overdrive. It started kicking in and out of overdrive. Tends to stay in the morning when its cool, but soon as it warms up it will go in and out. Other than that runs fine.

Any new ideas based on that?

The same shop says new tranny.

Not my rig, but my father in laws.
 

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No more "same shop"... Not for that tranny anyway, they don't know what they're doing with the Dodge Diesel OD at least. My opinion of course.

It could be as simple as a dirty ground. Could be the TPS, it is not supposed to be servicable but many people have taken them apart, cleaned them up and adjusted more voltage and been back in business. I would search the Diesel Truck Resource and the Turbo Diesel Register and do a potentiometer modification rather then fool with the TPS ever again. A new TPS is over $200 and less than $300, I forget the actual amount, Sorry. A potentiometer modification is under $5 bucks, read that five bucks.

There are upgrade parts available to allow more fluid to get to the OD section of the trans. which has been a problem, I would talk to someone about that. And you can have that OD section rebuilt seperate if necessary. Dave Goerand is good people, he specializes in Dodge diesel transmissions and converters. They are very busy I have found, and do not always return calls or email quickly. But they are very knowledgeable.
 
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