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hex0rz

OD and Tow/haul

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Hey guys, I got a rebuilt tranny job not too long ago. The guy put a tow/haul valve body in for me. It shifts later than stock to get the engine to rev higher. He said something about the OD button, but I can't remember. Would it still be ok to have my OD or should I still turn it off when tow/hauling?

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So if its flat, its ok for OD. But I start running into any grades that lugg the truck down, kick the OD off? Just trying to understand how much hill is too much for the OD.

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you will know when to kick off the od ,do not lug the truck,keep a eye on your egt,s[if you have a guage,if not, if you are going to do alot of towing you should get one]don,t let them climb over 1400*-1500* you will start to melt parts.these truck,s will pull amazing loads just use comon sence

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you will know when to kick off the od ,do not lug the truck,keep a eye on your egt,s[if you have a guage,if not, if you are going to do alot of towing you should get one]don,t let them climb over 1400*-1500* you will start to melt parts. these truck,s will pull amazing loads just use comon sence

Even at 1,200*F EGT's you got to be careful when you hauling weigh and/or trailer the coolant temps will rise very rapidily on you going up grade 6-7% so like THRacing mention I would highly suggest the gauges before towing and keep an eye all your gauges. Like myself I use 1,200*F limit on EGT's and drop a gear if the EGT's rising yet. So when you drop a gear and kick it back up to 2K on the tach it will be more torque but less heat produced so both coolant and EGT's should fall.

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you guys all missed the big part.what quality is his rebuild? is it even a billet torque converter?, billet single? or billet triple?.billet input? valve body? etic.These questions are more important then just what temps are safe to run.Granted the max temp is 1,250F anything over that is asking for trouble.Hauling with a true built trans is way different then what its life to haul with a stock auto.

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I have gauges. Boost, pyro, fuel. I spent the money on my BHAF, so when I can I will be getting some more gauges. One of them will be also a tranny temp gauge.The guy who rebuilt my transmission did not cover specifically what he put in. He asked how much I planned on towing/hauling and I said around 12k lbs. I don't wanna go over that weight as I can easily exceed manufacturers ratings for the truck.He put in a triple-disk torque converter. I wanted the 5-disk he had, but he said that a triple would be fine for how much I want to haul. He put in a tow/haul valve body to help with the shifting and make the engine work more than the trans.Nothing is billet. He did have to replace some hard parts because of the treatment received before I got the truck. I'm not sure about all what they were, but I know he had to replace the OD unit.

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I have gauges. Boost, pyro, fuel. I spent the money on my BHAF, so when I can I will be getting some more gauges. One of them will be also a tranny temp gauge. The guy who rebuilt my transmission did not cover specifically what he put in. He asked how much I planned on towing/hauling and I said around 12k lbs. I don't wanna go over that weight as I can easily exceed manufacturers ratings for the truck. He put in a triple-disk torque converter. I wanted the 5-disk he had, but he said that a triple would be fine for how much I want to haul. He put in a tow/haul valve body to help with the shifting and make the engine work more than the trans. Nothing is billet. He did have to replace some hard parts because of the treatment received before I got the truck. I'm not sure about all what they were, but I know he had to replace the OD unit.

i agree a 5 disk is over kill, and are only made my ATS (POS imo).....:lol: The mfg's ratings go out the window when you start modding the truck, the DOT only cares about axle and tire ratings and don't care much about what dodge says your truck will haul. did you get a billet flex plate installed as well? and im assuming a non billet input? How does it shift, can you feel it when going from neutral to say drive or neutral to reverse?

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What I mean by manufacturer ratings is tongue rating on my hitch and loaded weight in my bed. If I haul a gooseneck or 5th wheel, I cannot exceed what my GAWR for the rear is. Same with a hitch. I'm rated to only tow up to a 10klb trailer. With a maximum of 1k on the tongue.Just because my transmission may be able to handle this much weight now, that does not mean my drivetrain will. We all know the engine can handle a freightload! The guy told me that a 3/4 and a 1/2 ton are not much different from each other drivetrain wise. That was really depressing to hear it from him. :doh:No I did not get anything billet. My truck is stock performance wise. I have no power mods whatsoever. I sold my edge comp chip after getting my rebuilt tranny.Although, I wish I kept it as I could have used it to help me with my MPG fooler.As far as shifting goes, he told me it would shift firm. And that it does! I was definitely not used to how it shifted when I drove it home. He is a 2 1/2 hour drive one way. It was a nerve-racking experience as I could not tell what was supposed to be normal.It does have a jerk feeling when putting it into gear. I thought it was going to disappear when I got my rebuild, but its hard to compare as he changed it to a different valve body.When you drive, you can definitely tell when it shifts. I pulled my in-laws travel trailer (24ft) through various terrain and when I had the weight on it, you could tell it calmed the firmness down. The guy said that when I got a load on that I should not feel the shifting to be as harsh as when it is empty.To compare, before I got my tranny rebuilt I was getting 10-12mpg. Driving style was like a grandma. When I got my rebuild in, I jumped up to a whopping 18mpg! When I pulled the trailer, I got 15 mpg. I probably could have gotten alot better if I knew I could use the OD for certain times. I will definitely be getting myself an exhaust brake when I can come up with the money!

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I not so sure about the 1/2 ton and 3/4 ton drive line being that close to each other. But when abought mine back in 01 they dealer only had 2 dually's on the lot, both with autos. Dodge rated them at 16k truck and trailer. Mine with the 6 speed was rated at 20k, the 5 speed might be the same. At the time i had heard stories of the dodge autos not being up par and that is the main reason i wanted the manual. I had always assumed it was the tranny that made the beiggest differance. Did Dodge put a lesser drive shaft and rear end in the autos also? It just doesn't make sense especially in a dually?

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What I mean by manufacturer ratings is tongue rating on my hitch and loaded weight in my bed. If I haul a gooseneck or 5th wheel, I cannot exceed what my GAWR for the rear is. Same with a hitch. I'm rated to only tow up to a 10klb trailer. With a maximum of 1k on the tongue.

First, that 10,000lbs rating is a federal standard not a dodge one. Any trailer weighing over 10,000lbs must be hitched to the truck using a goose neck or a 5th wheel set up.

My Dana 80 axle is rated at 11,000lbs, even if i subtract the 3,500lbs that still leaves over 7,500lbs (with D rated tires that is what my door sticker says)..which if you do the correct trailer formula leaves me with a maximum trailer weight of +/- 30,000lbs which is about 25% of my Rear axle rating. (and that is being generous using 25%, the avg weight is more like 20%)

Just because my transmission may be able to handle this much weight now, that does not mean my drivetrain will. We all know the engine can handle a freightload! The guy told me that a 3/4 and a 1/2 ton are not much different from each other drivetrain wise. That was really depressing to hear it from him. :doh:

Explain what you mean by drive train, there is not much difference between 2500's and 3500 s my guess, minus the axles, your Dana 70 to my Dana 80.

No I did not get anything billet. My truck is stock performance wise. I have no power mods whatsoever. I sold my edge comp chip after getting my rebuilt tranny.

Should have a billet input and a billet flexplate, reguardless of what your builder says, a triple disk is way to much for a stock flexplate to handle. my flexplate was out of round and that was on a stock truck. added a 60lbs billet triple disk TC (an extra 20-25lbs) to your stock paper think flexplate and you will see why.

The stock flexplate is marginal now if you plan to tow with the truck that flexplate could trans your trans when it goes, and im not saying if.

Although, I wish I kept it as I could have used it to help me with my MPG fooler.

Why did you get rid of it? you trans is much tighter now you will find the extra power will be very beneficial. Especially since your running an HX-35 turbo, not the HY.

As far as shifting goes, he told me it would shift firm. And that it does! I was definitely not used to how it shifted when I drove it home. He is a 2 1/2 hour drive one way. It was a nerve-racking experience as I could not tell what was supposed to be normal.

It does have a jerk feeling when putting it into gear. I thought it was going to disappear when I got my rebuild, but its hard to compare as he changed it to a different valve body.

When you drive, you can definitely tell when it shifts. I pulled my in-laws travel trailer (24ft) through various terrain and when I had the weight on it, you could tell it calmed the firmness down. The guy said that when I got a load on that I should not feel the shifting to be as harsh as when it is empty.

To compare, before I got my tranny rebuilt I was getting 10-12mpg. Driving style was like a grandma. When I got my rebuild in, I jumped up to a whopping 18mpg! When I pulled the trailer, I got 15 mpg. I probably could have gotten alot better if I knew I could use the OD for certain times. I will definitely be getting myself an exhaust brake when I can come up with the money!

If said trans is as built as it sounds like in the last few paragraphs you should have no problem towing in OD

I not so sure about the 1/2 ton and 3/4 ton drive line being that close to each other. But when abought mine back in 01 they dealer only had 2 dually's on the lot, both with autos. Dodge rated them at 16k truck and trailer. Mine with the 6 speed was rated at 20k, the 5 speed might be the same. At the time i had heard stories of the dodge autos not being up par and that is the main reason i wanted the manual. I had always assumed it was the tranny that made the beiggest differance. Did Dodge put a lesser drive shaft and rear end in the autos also? It just doesn't make sense especially in a dually?

they are not close to the same, many people do not realize that the 2500 diesel versions are way different from the 2500 gas versions, i would think this is where his buddy got lost thinking they are the same.

The 2500 dodge trucks with manuals came with Dana 80's, the autos had Dana 70's, but the 3500 models all had Dana 80's regardless of transmission type or rear count.

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Pepsi, I need a little help on how you came with with a trailer weight of +or- 30k#. I can't quite grasp your math.

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Pepsi, I need a little help on how you came with with a trailer weight of +or- 30k#. I can't quite grasp your math.

My Dana 80 axle is rated at 11,000lbs, even if i subtract the 3,500lbs that still leaves over 7,500lbs (with D rated tires that is what my door sticker says)..which if you do the correct trailer formula leaves me with a maximum trailer weight of +/- 30,000lbs which is about 25% of my Rear axle rating. (and that is being generous using 25%, the avg weight is more like 20%)

The Dana 80's axle rating is 11,000lbs. Dodge subtracts 3,500lbs out of the mix to get 7,500lbs.

With load series E tires i can haul a 5th wheel trailer with a maximum pin weight of 7,500lbs.

Most 5th wheel trailers should maintain 20% of their trailers weight on the pin. but dodge makes the assumption of 25% or 1:4 ratio.

For example; I took a ~13,800lbs 5th wheel camper down to Florida, i rolled across the CAT scale at ~ 6,400lbs on the rear wheels, which is withing the weight limit of the rear axle. the pin weight was only 2,800lbs which is ~20%.

Same trailer came back up from Key West about 5 months later, rolled across CAT scale trailer this time was up to almost 21,000lbs, and yet when i subtracted the tare weight of the truck i got 4,200lbs for a pin weight (total was about i think 7,700 now)

With E tires i had a Goose neck trailer with a Formula 400 series on it, total load was 42,200 across scale. trailer + boat weight about 35,000lbs total. (tare of 7,200 for truck), yet my pin weight on the scale went to about 10,500lbs (or if you subtract 3,500 for the weight of the truck that leaves you at 7,000lbs which was roughly 20%. Now i was still legal but barely, talk withing 500lbs of legal.

All of my loads have been in the average of 18-23% of the total weight. most trailers are withing that range, any more then 25% and you have a trailer that is to front heavy, any less then 15-18% they are to but heavy. Unlike ball and hitch trailers which are between 10-15%, goose neck and 5th wheels should be between 15-25%. Dodge uses 25% in their "Safety Margin", thus why the total weight is lower.

This is how i got my numbers

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The most important thing I caught from all that is that my flexplate is gonna blow on me for not being billet?

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The most important thing I caught from all that is that my flexplate is gonna blow on me for not being billet?

i have spoke to several builders DTT and Goerend and they both stated that billet flexplates are more or less required(term used is heavily suggested) due to the stresses put into the flexplate by the weight and the torque put through it. The flexplate holds the weight of the triple disk torque converter, the weight of the TC is so much you run the risk of destroying the pump in the trans if the TC were to rest on the input shaft. the stock flexplate is more or less 1/8" steel, and when we put the trans up it was already warped, and this was a OEM trans coming out. (but then again this truck was a towing rig, so the flexplate saw use.

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I just scanned this thread and I come up with 2 issues, there can be No OD/Tow haul mode in the 2nd gens which brings me to the second point that the builder either misrepresented what he was doing or it is a simple miswording.The 3rd gens have a tow haul mode which does as you state it holds the converter in lockup mode longer so it doesn't lock and unlock as often this was how it worked through 05, 06 is when they offered OD/Tow haul which if you hit the OD button once it goes into tow haul mode if you hit the od button twice it turns od off.This is programmed in the pcm, 2nd gens do not have this and are not capabler of this. you have od on off and that is all. With a modified valve body they up the pressures and can change shift points but there is no tow haul mode.The early 3rd gens up to 04.5 could be reprogrammed to gain both tow haul and od off but the 05 year could not be programmed to get both but there are aftermarket shift control boxes that will turn off OD.

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I just scanned this thread and I come up with 2 issues, there can be No OD/Tow haul mode in the 2nd gens which brings me to the second point that the builder either misrepresented what he was doing or it is a simple miswording. The 3rd gens have a tow haul mode which does as you state it holds the converter in lockup mode longer so it doesn't lock and unlock as often this was how it worked through 05, 06 is when they offered OD/Tow haul which if you hit the OD button once it goes into tow haul mode if you hit the od button twice it turns od off. This is programmed in the pcm, 2nd gens do not have this and are not capabler of this. you have od on off and that is all. With a modified valve body they up the pressures and can change shift points but there is no tow haul mode. The early 3rd gens up to 04.5 could be reprogrammed to gain both tow haul and od off but the 05 year could not be programmed to get both but there are aftermarket shift control boxes that will turn off OD.

Actually the dodge manual says that tow haul mode is O/D off, it prevents the trans from going into OD which according to my book is only suggested for light towing. But you are correct there is no official tow haul mode that changes the shift points because the shift points are controlled by the TV cable, so regardless of the O/D on and off switch putting a heavy load will drag every gear farther back except the OD which is controlled electronically regardless of TV settings.

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Actually the dodge manual says that tow haul mode is O/D off, it prevents the trans from going into OD which according to my book is only suggested for light towing. But you are correct there is no official tow haul mode that changes the shift points because the shift points are controlled by the TV cable, so regardless of the O/D on and off switch putting a heavy load will drag every gear farther back except the OD which is controlled electronically regardless of TV settings.

Yes this info refers to 2nd gens only, i WAS NOT AWARE THE 2ND GEN MANUAL CALLED OD OFF "TOW HAUL" oops hit the cap lock. The 3rd gens have both functions "except for 05" they have or can have an actual tow haul and OD off function.

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Okay, I went with this guy cause he has owned his own transmission rebuild shop for about 30 some odd years. He deals with alot of guys who pull some weight. He never mentioned anything to me about needing a billet flexplate. I would assume he would say it is something I should get done if it needed it? I just spent almost $4,500 on this rebuild! :mad:Moparman, I don't get what you mean by grabbing a gear lower in an auto? Like manually moving the gear selector down to 2nd or 1st?Pespi, so you are saying that I should only have the OD button ON when I'm only towing lightly?I'm not sure what to do now... I feel like I just bought a $4500 transmission rebuild that I can't even use for work...

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you did not spend 4,500 for nothing . tow in od ,when you come too a grade ,or get into heavy hill,s turn off your od you will be fine. just keep your eye on your get,s ,don,t lug your motor down you will be ok.drop a gear =shut off the od

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Well, seems like from the sounds of the way pepsi makes it sound, I'm just once again a ticking time bomb waiting to happen. Even if I do not pull a load. But just from the sheer weight and torque that can be applied to the flex-plate from the TC.I'm gonna call my transmission guy when he opens and run it by him and see what he has to say on the matter. Other then that, besides my potential flex-plate issue, just make sure to kick off the OD when I'm not on flat ground.I'm gonna look into an auxillary transmission cooler as well. I thought these trucks had a core in the front, but it looks like the fluid is cooled by a heat exchange with the coolant?

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Okay, I went with this guy cause he has owned his own transmission rebuild shop for about 30 some odd years. He deals with alot of guys who pull some weight. He never mentioned anything to me about needing a billet flexplate. I would assume he would say it is something I should get done if it needed it? I just spent almost $4,500 on this rebuild! :mad:

Moparman, I don't get what you mean by grabbing a gear lower in an auto? Like manually moving the gear selector down to 2nd or 1st?

Pespi, so you are saying that I should only have the OD button ON when I'm only towing lightly?

I'm not sure what to do now... I feel like I just bought a $4500 transmission rebuild that I can't even use for work...

I spent not much more and got a fully built DTT trans:cookoo: (with billet input and flexplate.

There is alot of difference between the two, and im not sure what your guy would say, but both DTT and Goerend recommended billet flexplates to me mainly because they stock ones can barely hold the stock power level, let alone the harsh shifting of trans.

(If your adding a pac brake down the road i would also suggest a flexplate because your fighting gravity with that thing.

As for towing/downshifting this is what i follow. and DTT told me that with my trans i should be fine to haul what i need in 4th. Basically i have always hauled in O/D to get what i need where i need it, IF your truck cannot make its mind up as to what gear to select (either 4th or 3rd), or keeps shifting then slow down and go to 3rd gear. This is what i have always done, its better to drop into 3rd which is 1:1) and then let the truck work from there, then have it struggle to hold.

Basically you start by hitting the O/D off button, then that kicks it into 3rd gear, once you climb down to about 1,300rpms(+/- 40mph) you can then downshift to the "2", or to the "1" selector as i have found that my truck will not downshift into first until the PCM reads 25mph.

--- Update to the previous post...

Well, seems like from the sounds of the way pepsi makes it sound, I'm just once again a ticking time bomb waiting to happen. Even if I do not pull a load. But just from the sheer weight and torque that can be applied to the flex-plate from the TC.

I'm gonna call my transmission guy when he opens and run it by him and see what he has to say on the matter. Other then that, besides my potential flex-plate issue, just make sure to kick off the OD when I'm not on flat ground.

I'm gonna look into an auxillary transmission cooler as well. I thought these trucks had a core in the front, but it looks like the fluid is cooled by a heat exchange with the coolant?

the 2500's have a built in trans cooler with the radiator (I believe, says haynes manual i have)

Im not saying your trans is worth less, for 4,500 you better have one that can pull a mountain, i just feel that you should have a flexplate at the least, because everyone i have talked to seems to be in agreement about running flexplates and triple disk TC's.

You can stay in OD when not in flat ground, just understand that without the added power your engine will be bogged down more easily, and i should also add put more load on the engine. as long as your not constantly shifting from 3-4-3-4-3-4 your good. If so then kick it out of OD and slow down and then kepe going.

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I was torn between too many transmissions online. If I was able to make a decision I would have had to DIY it. Which is not a big problem for me. But then there is always the possibility of the transmission being bad on arrival and them placing blame on me. I would have had also had to send mine in for the core.Chances are, I would of had to pay more for the core when I sent it in as I had some hard part damage. Choosing someone I can go to in person and speak with them 1-on-1 was better IMO. I paid someone to deal with the headache I would of had. As I know nothing to little about rebuild transmissions. Not only did they redo the transmission, but they check the cooler lines, and the electronics involved with the operation of the transmission. If had gotten an input or flexplate, it would have been nearly $5k for the job, and I was already breaking the bank with $4.5k.I called my transmission guy today, and he told me that he has only replaced 10 flexplates in the last 5 years. But thats what only comes through his door. He said most of the time they are diesels. The reasoning behind broken flywheels for him is not what you describe. Mainly due to a bad starter or cracks developed from vibrations. Nothing from the transmission is going to cause the flywheel to go out because it is not the cause for broken flywheels. According to him...He quoted me about $400-500 to do a flexplate job with a stock flexplate. So add that to however much it would cost me for a billet.In reality, I have to take what I read online with a grain of salt. As most of it can be hearsay. I also have to take the transmission guys info for what its worth as well. I will continue on a stock flywheel until it goes out, if it does go out. Then I will fork the money over for a billet when the time comes. Although, I will heed all advice on how to be easy on the transmission when hauling/towing.

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I would like to ask? Has anybody ever trashed a flex plate due to to much load. I mean real seen it not just heard of it. Maybe with a over abundance of power adders and foolish driving. I have personally done some stupid things with my trucks and drag racing for years and never broke a flex plate. Unless your running more than 500 hp, just drive it, enjoy it. The engineers that designed these trucks did take into consideration our ability to do dumb things with them. There is always room for improvement, some things are just overkill. Scare tactics sell parts. Just my 2 cents MEH

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