Engine/Transmission (1994 - 1998) Gear Vendors under/overdrive question.

[KOwens]

I've been trying to understand the limitations of my 1995 Ram Cummins with the 47RH automatic transmission... with my 3. 54 rear end ratio. The 0. 69 overdrive is "very tall" and I am now beginning to slip... again... while trying to tow my 28 foot trailer in overdrive... even on small hills or on flat highway in strong head winds.



At any rate, I have read all I could find on the TDR concerning the 47RH's limitations and why the "stock" friction surfaces break down and fail. Seems low engine RPM... like in overdrive... lead to low transmission line pressure, equals heat, equals burned out friction surfaces, equals transmission overhaul.



My frustration is that even with the 3. 54 rear end, it is painfully slow to tow without the overdrive. :{



Can anyone out there in TDR-land using the Gear Vendors 0. 78 ratio under/overdrive tell me what they think of this setup. Based on what I have read and calculated, I could tow using the GV unit at 65 MPH at about 2000 RPM without using my stock overdrive. That sounds a lot better than my current 54 MPH at the same RPM without any overdrive.



Please tell me what you know about the problem and possible solutions... especially experience with the Gear Vendors product.



Thanks Kevin

 

[TGaines]

I believe there was a member on this list by the name of turbo thom that had the gv overdrive. I believe he had a 4. 10 rear end though. I too have thought about going this route as I have a 4. 10 rear. I have been told good and bad things about the unit. Some say it lasts forever, others say it's junk and can't handle the power. I top out at 70 in od with my rear end and would love to get a few more mph out of my rig. I just can't see spending the money at this time though. I have often wondered if a 3. 73 would be the ultimate way to go, but have heard you need to change the carrier to switch to the new ratio. I guess I'm just stuck. Wish I could be more help.



Travis

 

[jtwcummins]

You should be able to top out at about 85MPH w/4. 10s. Mine from day one cruises at 75 w/o any strain and hits between 85 and 90 before the guv starts cutting back fuel. About 2 yrs ago it wouldn't go above 2500 rpm. Checked and found the throttle cable wasn't opening the rack completely. Replaced cable and back to where I was.

4. 10 gears make towing nice but you pay for them everyday. I ordered those gears because it was the only way to get Limited Slip, not available in 96 or 97 3. 54 gears.

 

[Doubleclutch]

I got my GV in 2000. Apparently the GV folks made quite a few improvements in 1999 to answer the weaknesses of the previous designs. With a 5 speed, 4th over is very close to 5th... but won't toss off the fifth gear nut! I've been happy with my GV. 93 mph at ~2000 rpm (gps speed).

 

[TGaines]

How do you get to 85 before the rpms run out. I have 235's on my truck which are way taller than the stock 215's and at 70 I'm at 2350 on the rpms. I don't want to rev much higher than that to prevent engine wear. Maybe I'm paranoid but I didn't think high revs were good for these engines. I had the throttle cable replaced under the recall but it didn't increase my revs any.



Travis

 

[JNailor]

Kevin,

I may be all wet here as I don't have a slush box, but I think the overdrive clutches are applied by a large spring, not hydraulic pressure. Regardless, if it were mine i'd spend the money on a quality transmission and converter rather than an add-on overdrive. From what i've read they really enhance the total driving experience as well as the reliability. Just my two cents. Dana

 

[Howard Durand]

I have a 94 with the 47RH and 3. 54 gears and understand the challenge you are faced with.



The only thing I have done for the transmission is change out the TC with an aftermarket, low stall TC and replaced the valve body with an enhanced one from BD.

I also use a switch to control the TC, mostly for braking, but it does come in handy at other times as well.



Once you have a transmission that will hold, then power enhancements will help you overcome the problem with the high gear ratio and big jump into OD.

I considered the GV at first but with it you still need to upgrade the 47RH and I have found what I have done to be sufficient.



I'll have to say that the last modification I did to the engine produced the most dramatic change of all and that is replacing the governor springs with the 3000 GSK .



Even before the GSK replacement, I pulled our 30 foot TT over most of the hills between central Washington and eastern Wyoming in OD.

Now I may even be able to make it over Lookout Pass in OD.

 

[KOwens]

Howard, et. al. , ... thanks for the info.



I've also been trying to do my homework on aftermarket torque converters, valve bodies, and complete transmissions in an effort to determine the best path to "customer satisfaction. "



What I didn't want to do is spend as much as $3500 for a full-blown transmission/valve body replacement... only to find I experience the same problem when towing in overdrive. And trust me, I've considered throwing down the money so I can smile again while towing my trailer.



Not being an automatic transmission expert, however, I am having trouble following the TDR discussions that describe "all" the different friction clutch surfaces within the 47RH transmission. If I buy a "triple-lok" torque converter, for example, and beef up that clutch surface, does the problem simply migrate to the next weakest clutch and fry it? There's the TC clutch, front clutch, overdrive clutch... etc. But you've only upgraded the TC clutch... is it the valve body that is making the other clutch surfaces last longer? Is it increased line pressure or what?



For whatever reason, it seems I can tow anything I want when I don't use the overdrive... it's when I drop the RPM in overdrive that things start going way wrong in a hurry! Thus the new interest in a 0. 78 overdrive unit from GV versus the stock 0. 69 overdrive found in the 47RH. In a perfect world, perhaps both upgrades would be a good idea. But money will get in the way... so that's not going to happen.



I too want to increase my Cummins torque and horsepower output for towing, but want to make sure I've got a gear box that can take the abuse... especially considering the cost of these enhanced transmissions or aftermarket GV overdrive units... and what I'm hearing from you is the upgraded torque converter clutch/valve body will do the trick, and no add-on overdrive is necessary. Please let me know if I'm reading you right.



Thanks everyone... Kevin

 

[jcarey]

Just for whatever - my . 02 ... I would think either a ATS or a DDT replacement would allow you to tow without slipping, but so would the GV because you, in effect, have more gears available. I'm leaning toward a GV because I would also expect better mileage, since (and this is only opinion) you have more chances og being in the most efficient gear. The ideal situation to me... a combo. Jim

 

[Howard Durand]

It is my understanding that the weak link in the 47RH/RE transmissions is the TC clutch. The upgraded TC improves the fluid coupling and beefs up the clutch surfaces.



The valve body is upgraded to provide positive shifting and added pressure to hold the TC clutch engagement under heavier loads. I don't think the OD assembly is part of the problem.



I have talked to Bill Kondolay at DTT about mine a couple of times and though I have never bought anything from him, he answered my questions and didn't try to sell me something that I didn't need.

You will probably find the same with most of the experts that are talked about on the forum.



In my experience, the dramatic drop in rpm doesn't occur following the shift into OD but when the TC locks up right afterward.

The stock truck couldn't handle that but now it does quite well.



If a hill proves to be too much for the truck in OD with the TC locked, I use the TC "mystery switch" to unlock and stay in OD.

If the hill proves to be too tall it will eventually shift down to 3rd which won't be too bad now with the 3K GSK in place.

 

[KOwens]

Hello again Howard... and thanks for keeping the dialog going,



I appreciate your insight on the "weak link" in the 47RH... and I'm glad to hear you have found a good solution for the towing problem and slipping we have both experienced.



I have read the complete write-up on ATS Diesel Performance's "ATS University," and I'm impressed with the detail they went into describing the problems with the stock transmission and what they have done to improve towing capability... even in overdrive. Their TripleLok torque converter, improved stator design, valve body, and TC clutch controller also sound like decent products. There have been times when I would like to lock the TC in lower gears... and not have it unlock each time I let my foot off the pedal. Do you have any issues with the ATS products?



By the way, when my truck was about 3-1/2 years old (yes out of warranty :-{} ) my 47RH was overhauled at about 60,000 miles due to major slippage, but was not rebuilt using any of the upgraded parts I am just now learning about. I regret my decision in choosing the particular shop I went to... and I let my wallet make the decision... instead of educating myself first and getting the job done right. My son and I pulled the transmission out again about a year and a half ago to replace a broken kick-down band lever... so I got a good look at the torque converter when we pulled it to get the lever reaction pin out. The TC is the stamped steel type with welded nuts on the perimeter.



I've now got about 182,000 on the truck, which means the overhaul lasted about twice as long as the factory build, but then I haven't been towing in overdrive much either. So I have been suffering at slow driving speeds for many years... so that my transmission could last a bit longer while towing.



The driving slower part is mainly because my motor sounds like it is really laboring at anything above about 2400 RPM. Is this because the governor is limiting fuel from the injector pump? Can you tell me about the 3K GSK spring kit and what is involved with this installation? I would like to know what the benefits are before considering this upgrade... and what else I must do to make it an effective modification. As an example, I am still running the original "factory" injectors (160hp ???)... they have never been removed from the motor. Do I need to upgrade the injectors... or should I leave them alone? I see a lot of chatter about Peirs injectors on the TDR... I just have no experience with the pros and cons of making an injector modification.



I do have an "aftermarket" fuel plate installed (not sure about the number) that a workmate installed for me. He simply told me it would increase power... and it has, along with the wastegate adjustment that has increase my max boost to 25 PSI. Is the GSK the next step in my performance upgrade evolution?



Thanks again for you comments... I do appreciate your time.



Kevin

 

[jimk]

Originally posted by KOwens

I've been trying to understand the limitations of my 1995 Ram Cummins with the 47RH automatic transmission... with my 3. 54 rear end ratio. The 0. 69 overdrive is "very tall" and I am now beginning to slip... again... while trying to tow my 28 foot trailer in overdrive... even on small hills or on flat highway in strong head winds.



At any rate, I have read all I could find on the TDR concerning the 47RH's limitations and why the "stock" friction surfaces break down and fail. Seems low engine RPM... like in overdrive... lead to low transmission line pressure, equals heat, equals burned out friction surfaces, equals transmission overhaul.



My frustration is that even with the 3. 54 rear end, it is painfully slow to tow without the overdrive. :{



Can anyone out there in TDR-land using the Gear Vendors 0. 78 ratio under/overdrive tell me what they think of this setup. Based on what I have read and calculated, I could tow using the GV unit at 65 MPH at about 2000 RPM without using my stock overdrive. That sounds a lot better than my current 54 MPH at the same RPM without any overdrive.



Please tell me what you know about the problem and possible solutions... especially experience with the Gear Vendors product.



Thanks Kevin

I bought a used gear vendor and never used it because I would have to buy a kit to install it and then pay 3. 5 to 4k dollors to install a automatic. Easer for me to get rid of the 95 or install a 6 speed. The truck is payed for but I am not married to it. I have looked at the ratios and the 6 speed looks right for towing with the 3. 54 gears. The rpm drop is to high for my uses between the 3 and 4 gear. I have a governor kit lol also. jimk

 

[Howard Durand]

Kevin,



I certainly have no problem with the ATS transmission. I considered going that way at one time but the cost couldn't be justified since I already have an early BD low stall TC and valve body. They have served me well even though the older BD convertors were nothing more than reworked stock covertors.

I tow a 30 foot Holiday Rambler Free Spirit travel trailer which makes the total weight of the combination about 15,000 lb.

This is not near the weight some people tow but is near rated capacity for my truck.

It pulls it well and in OD most of the time thanks to the mods I have done.

When the truck was stock, the small hills kept me shifting in and out of OD, not anymore.

I am not sure but I think your 95 auto has a 180 hp pump. Mine is a 160.

I put in a set of 215 injectors that I bought from Piers but couldn't see that they made all that much difference.

The 3K GSK was my last upgrade and has produced the most dramatic improvement in the performance of the engine.

They cost $125 plus shipping from Piers and are quite easy to install.



There is some great information on the GSK installation at Relentless Diesel Performance's web site at the following address: http://www.flex.net/~triplem/new/govspring.htm



To install mine, I completely removed the fuel shutdown solenoid and the bracket. That gives a good view and access to the plug and to the springs.

I haven't been able to take the trailer out since I put them in and can hardly wait.

If you want to drive a new truck, just install the GSK.



In my opinion, if you want to tow heavy loads at highway speed, you will need to upgrade the TC and valve body no matter whose product you choose.



Early on, I installed a switching scheme commonly called the "mystery switch".

I use it mostly when towing. It's primary purpose is to allow me to lock up the TC when using the exhaust brake but it also allows me to unlock the TC and stay in OD when pulling hills. It allows me to keep the rpm up and hold the exhaust temperatures down.

Quite often, that is all it takes to get on over the top, if not then it is time to drop back to 3rd and let the TC work as it should.

I see no reason why you need to do all of your towing in 3rd.



Hope this makes sense,



Howard

 

[KOwens]

Hi Howard,



Thanks for the continued input... I appreciate your help!



The Relentless Diesel Performance website you directed me to really helped in understanding what I would have to do to install the 3K GSK. Doesn't look that bad to me from what I saw on the website! Any tricks I should know about in making the final adjustment? By the way, did the Pier's GSK come with any instructions or pictures or diagrams... to step you through the process? I know it's always comforting the first time through a mechanical procedure to have a guide of some kind.



Also, I concur with your assessment on the need for a transmission upgrade... and that will probably be early this summer for me. With the mileage I have on my rig (182K), I am leaning toward the complete ATS built transmission swap, which comes with upgraded "hard" parts and gears, low-stall-speed stator, their advanced valve body design... and add the TripleLok TC with the TC-clutch controller. I feel the modifications I have done on the engine currently "out perform" the capability of the transmission to keep up and remain reliable. And like yourself, I want to feel confident while towing... knowing that it will hang together and not slip using the overdrive when appropriate.



By the way, have you ever upgraded you transmission cooler lines? I've heard the "quick disconnect" connections can break or separate and leave you stranded. I'm not sure what model years this affects... I'll have to try and find those old TDR posts. If you have performed any upgrades in this area, I like to hear about these as well.



Again, thanks for all the advice, I do appreciate your time, Howard.



v/r Kevin

 

[Howard Durand]

Kevin,



The GSK kit does come with instructions but I found those from Relentless Diesel Performance to be superior.



I don't think I would want to try to install the springs from the top. The side method was quite easy once all of the obstructions had been removed. Also, there is no danger of dropping something into the pump.

You have to be careful when removing the bellcrank from the fuel shutoff valve shaft that you don't lose the little woodruff key. It is small and lightweight and easy to drop. Having the solenoid and bracket completely removed improves visibility and access to the site. A drop of STP on the key helped hold it in place in the shaft when reinstalling the bellcrank.



The measurements of the stud protrusions is critical and you need to figure out a way to do it accurately. It takes a little practice but it is not real difficult. I used a vernier caliper and feeler gauges.



As to the transmission cooler lines, I made the mistake of replacing the push on connectors with brass compression type connectors. They are not a good idea. One of them started leaking very bad and I didn't have time to deal with it so had the truck towed to the dealer and they replaced all of the lines with the new steel lines. It was costly but much better and more reliable. They use flared fittings which are much better.



I am not sure but I think yours has the quick disconnect fittings with the plastic bushings. It would be a good thing to replace them.



Hope this helps,



Howard

 

[KOwens]

Thanks Howard for the advice,



I will take it slow when performing the 3K GSK R&R. I own a good dial caliper... so I'll figure out how to take a good measurement. Do you remember the setting you ended up with (0. 030 or 0. 040) after the GSK install? Which setting is better with the low-stall-speed TC? Unfortunately, I have a few pressing matters to attend to this month and next, but I plan to jump on this in early May. Long before summer vacation and our next big towing trip.



Also, next time I'm under the truck doing an oil change, I'll take a closer look at the transmission cooler lines. Do you know if an aftermarket, TDR-endorsed replacement line kit is available? Or is it only available through Dodge? It would be nice if I didn't have to purchase them from the "stealership" ... unless of course, they are better or cheaper for some reason (ha!).



At some point I'd also like to add a transmission temperature gauge in the cab. I currently have boost and EGT only. Do these new cooler lines help incorporate a transmission-temp sending unit... or do you somehow share the threaded boss in the current transmission line used by the PCM (bird brain) sending unit? Hopefully this makes sense to you... if not, no worries.



Anyway, thanks for all the good advice... I do appreciate your time.



v/r Kevin

 

[Howard Durand]

Kevin,



I don't know of any after market lines to replace the ones from Mopar. At the time mine were replaced, 1998, they were about $365. 00 just for the parts.

They are probably worth it as they fit the truck but they only have a sender port for the temperature sensor that the PCM requires.

I modified my transmission pan and installed both a drain plug and a temperature sender port.

There are pros and cons about where the temperature should be monitored, pan or TC outlet, and I think it is mostly a matter of preference.

If you want to know how hot the fluid is coming from the TC, I think you could incorporate a port at the TC outlet for the sender.

I have considered installing one and just switching the gauge between the two.



As to the GSK stud protrusion:



The stock settings in mine were as follows, one side had 0. 040" protrusion and the other had 0. 046".



Wnen I installed the new springs I set them both at 0. 036"



Once they have been set, any changes can be made by tightening or loosening them a click at a time.



The nuts and associated washers are made with meshing teeth on their mating surfaces and there is a definite click when the nut is turned either way. The washer is keyed to the shaft so it can't turn.



I am pleased enough with the way my truck runs that I didn't make any changes from the settings I chose.



Good luck,



Howard

 

[KOwens]

Hey Howard,



$365 :--) YOUCH! Do they rub your feet while you're making out the check? Oh well, I guess that's better than being stranded along the side of the road with your trailer, laying in a puddle of transmission fluid in the hot sun with your family yelling at you... why didn't you fix those lines when Howard told you to?



I too have installed a drain plug in my transmission pan... and man-o-man does that help with filter changes and adjusting the rear band... making that job a lot cleaner. I'll give some thought to the TC versus pan sending unit location issue when I get the bug to replace the cooler lines. Thanks for the advice.



But now you have me really confused. Did you say two sides to the GSK stud protrusion? Having never seen these parts before... removed or otherwise, I'm not sure what you mean when you say one side was different than the other. I didn't glean this from the images from the Relentless Diesel Performance website. I guess I figured it was adjusted from one side only. I'm sure I've worn out my welcome by now... but if you can tolerate another question, could you explain what these parts look like once removed from the P7100 pump... or at the time I am supposed to take this measurement? If you want to pass, I fully understand... and it will probably make sense to me as soon as I get that far in the process, but my engineering brain is begging for answers. Help me O-B-One!



OK, Howard, have a good one and I'll talk to you later.



v/r Kevin

 

[Howard Durand]

Kevin,



There are two sets of springs mounted on separate studs opposite each other in the pump. They work like a flyball governor.



After you remove the access plug in the side of the pump you rotate the engine until the first set appears and is centered in the hole like they are shown in the pictures.

When you get the first set replaced, mark the washer with a felt tip marker, then rotate the engine unil the second set appears and repeat the process.

The reason for marking the washer is to make sure you don't rotate past the second set and change the first ones again.



Three of the pictures at Relentless Diesel Performance's web page show the assembly as it appears when removed from the pump. Another picture shows what you will be seeing when it is in the pump with the plug removed. This is the situation you will have to work with. The measurment you need is how much the stud protrudes from face of the nut.

Once you have that you can remove the nut with a narrow screwdriver in the slot on either side of the stud. It turns easily but you will be able to feel it click as you rotate it. When you get it off, turn it over and you will see the teeth that mate with the teeth in the washer.



What you get in the 3K GSK is a total of 4 springs and 2 spacers.

The instructions give good directions on which components are replaced.



Howard

 

[KOwens]

Hi Howard,



Thanks again. It makes sense that there would be two "opposing" spring sets on the governor. The photos on the Relentless web page caused some of my confusion... by showing the springs extending out of the access hole... in a position they clearly could not rotate in.



With the help you have provided, I feel I have a better understanding of what is going on, and I should have no problem with the spring set replacement.



When I get this done, I'll try to send you a private message with the results. Again, thank you for taking the time to explain this process in detail. I appreciate it!



v/r Kevin