24v Cummins Towing Custom 2nd Gear Lockup on 7% Grade

[@zachmazur4553]

Nice job on the trans build. Such an awesome video. I have a 47re in an early 3rd gen. Really would like lockup in at least 2nd for towing and Pacbrake.

[@tittledieselperformance]

3rd gen’s all had 48RE’s which look nearly identical to the 47’s. The 48 valve body already has the M2 passage blocked so you should be able to achieve 2nd gear lockup already you just need the switch to override the computer and force it on. A way to tell is go to M2 and run it to about 30-35mph area and you should notice lockup occur on its own. That’ll tell you if the switch will even work. Couple of notes though, exhaust brakes and automatics aren’t a very good mix. Your creating a negative torque state with the engine which is what slows you down but the problem is the throttle valve on the trans isn’t being rotated under this conditions which can and will slip the transmission because line pressure is at “idle” and not intended to have any real load put on it. Most exhaust brakes depending on adjustments and other factors can cause about a 200-250ft lbs drag on the transmission that it’s not setup to deal with. Some custom setups have installed solenoids to alleviate this problem. Be warned you can damage the 2nd gear band, Rear Clutch (one engaged for all forward gears at all times) or 3rd gear direct pack on decel. Pay very close attention to the tach and any vibrations you may feel in the floor.

[@zachmazur4553]

I really appreciate the thought in the reply. Truck is a late ‘02 build and vin also says it’s not the 48. Currently does not lock in 2nd. Any idea how to get line pressure while at idle in D or M mode? I did not even think about that issue. I saw on a mopar forum that folks measured this pressure after your reply. Trans was rebuild by previous owner but not sure what was done. Replaced TC when I got it. Was going to do a valve body next (I think it’s oem). And add the pac and figure out 2nd lockup. I have a dump body on the truck and pull trailer.

[@tittledieselperformance]

@@zachmazur4553 interesting yours must have a 47 left over. I haven’t come across one like that before. You’ll want to do some valve body work before using the brake then. The stock valve body is most of the reason people have issues with the 47/48’s to begin with because they setup the pressure curve so low for emissions and fuel economy compliance. Do you have any tuning or anything done to it engine wise and will you in the future? To get 2nd gear lockup requires a passage on the overdrive separator plate of the valve body to be brazed closed. It’s a pretty involved process to do. Another easier way would be find an actual 48RE valve body and swap it in since that passage is already blocked anyways. This will also help bring line pressure up a little bit. I mainly use Transgo shift kits on them with some small other modifications. Biggest things you’ll want is minimum a shift kit in the VB, if your gonna tune it beyond like a 40-60hp tow tune you’ll need a triple disc converter and with that probably a billet input shaft. Those 3 items alone are kind of a bare minimum to get these transmissions rock solid to be able to handle towing and power stress without failures. As for the line pressure thing for the exhaust brake you can design a solenoid to pull the TV level on the trans back about 60% and hold there to get the line pressure rise needed for the brake to work right. I don’t know of any kits to do this off the shelf since no one really does it to an automatic.

[@zachmazur4553]

@@tittledieselperformance it has a Smardy on the lowest setting. Which actually helps lol trans was rebuilt but not sure what was done with it - pan is still oem which makes me think not much. But feels good for what I’ve been doing. I had a low stall triple disc TC installed. Not sure if input or flex plate is billet. I’m debating ordering a revmax VB. once I drop the pan I’ll see if anything has been done and maybe I’ll get to send it back. I think I could then add a switch for 2nd gear lockup. The Pacbrake should kick it into lockup if I wire it like a 48 (unless it’s the same way). The TV level seems like a real issue and I don’t see Pacbrake mentioning it, wonder if anyone has measured it

[@mc-mk9oj]

Could you do a video on your air ride system ? Its something I've been looking at but theres not much information around I can find

[@tittledieselperformance]

That specific truck isn’t around now but my new one has the same system. I can do a video on that one. It’s just a Airlift 5000 system with the onboard compressor and gauge. Make sure you get the one WITHOUT the bump stop in the center. It’ll show a white bump stop inside the bag on the website. Make sure you don’t have that one or it’ll limit suspension travel and ride like crap

[@mattk252]

Even Jesus won't take that wheel 2nd gen life!

[@tittledieselperformance]

No play in it I've got bump steer currently

[@twinturbo327]

Grab the bottom of your steering column and shake it. There is a centering cone the has a spring that losses tension and causes wondering. I replaced the gear box, shaft track bar etc and the steering column fixed it.

[@tittledieselperformance]

Mines actually from bump steer, I’ve got a heim joint track bar currently but haven’t done the drop pitman arm so it moves around in my hand as I’m climbing the hill. I use image stabilization so the bumps don’t appear in the video. I’ve got a drop pitman and low reduction box to swap out that’s shimmed better anyways.

[@Snekkens]

The round ignition key is bugging my ocd lol

[@Rx7man]

Looks like a pretty long hill! Like any 2nd gen, you seem to have to herd it down the road a bit

[@tittledieselperformance]

Unfortunately she's actually got some bump steer currently till I get around to doing my drop pitman arm to match the trackbar angle. It pushes the wheel around a good bit. The 24v trucks with a factory Mopar steering box also have more steering reduction so you gotta move it a little more then pre 98's

[@Rx7man]

@@tittledieselperformance I heard it was all the dually trucks that had a 20:1? reduction and the SRW trucks had a 16:1?... can't remember the real numbers on it but the dually trucks were a slower box... I plan on putting a SRW box in my dually I drive a lot of winding roads, I was wearing my tires on the outside edge a lot, I put a 1/2* camber bushing in and gave it a bit more caster, really smartened up the truck on the road and my tire wear has been more even

[@adrianchapa7706]

Whats the gearing ratio?

[@tittledieselperformance]

3.54's....its getting 4.10s and a trutrac soon

[@bigmurph1447]

To low of a stall converter? Why is that

[@tittledieselperformance]

I ordered this converter with a very low stall for my 12valve, it works fine for stock/pump only daily drivers who don't tow heavy but I bought this to make my 12valve a race rig, 24v heads don't have swirl ramps and the cam has a much higher LSA for more upper rpm focus so at the 1400-1600 stall where this converter was, it bogs the engine down too hard making it sluggish do to the lack of torque multiplication. I've since changed to a 2000-2200 stall (stock) and its much happier. It allows more response with the throttle allowing more rpm to grunt against the input shaft and get the load moving and build boost easier keeping the bog down. Torque multiplication is a key factor.

[@bigmurph1447]

@@tittledieselperformance i have a goerend 15ss low stall.in my 96 with 3.55 gears and it works great for towing. Have a 97 with a dpc stock stall with 4.10 gears and it sucks. My 96 will out run it pulling my 25ft gooseneck with a 9000lb skid steer on it.

[@tittledieselperformance]

@@bigmurph1447 Whats done to the pump on both trucks? Most people complain about the stock stall speed on a stock-ish truck because it seems like its revving too high but there is fuel economy reasons for it. Lower stall feels better driving but for actual efficiency around a 1700-2100 stall is perfect. 12v trucks can handle a lower stall speed a little better. Typically 1700-1900 area is best with just pump work.

[@bigmurph1447]

@@tittledieselperformance my 96 has no fuel plate 7x11 injectors 024dv 4k govsprings afc mods 18 degrees of timing and compound turbos. 97 was set up the same way. Before I added compounds

[@tittledieselperformance]

@@bigmurph1447 interesting. What Compound setup? With governor springs you shouldn't have issues with the stock stall 2000-2200 area with the DPC converter. Most people think it revving that high doesn't feel right and visually looking at the tach it seems really high but in reality its fine for pulling, it may not seem like the torque is being applied but that's how multiplication works, it takes more rpm to achieve the stall effect inside. Its essentially an illusion. 12v heads have swirl ramps and the factory cam is very bottom end focused (below 2200rpm) , since it stalls high above peak torque (1600-1800 area) it seems like it doesn't work right but if you took 2 identical engines (stock with exhaust, governor spring and no fuel plate) with 3.54 gears on 35's and drag raced towing a trailer the stock stall would get off the line faster. If you had a first gen non lockup then a low stall really helps a ton but there intentionally left loose to get the load moving with the tall gearing in the transmission/axles then when lockup engages it physically pulls harder. Low stall units transfer power more efficiently unlocked at lower rpm with most loads but it will have a harder time getting a load moving with the same amount of fuel injected. I know the feeling your talking about though, I've run 1400-3000 stall converters with 12 and 24v blocks with various turbos and agree the lower stall units do feel good but there's some situations such as mine in the video where its loading the engine at such a low rpm that it cant slip the converter enough to get moving but once moving it feels fine. That's kind of why I switched back to stock. It literally felt like I removed 2000 lbs off the truck, yes it shows more rpm but the actual engine load (fuel injection calc) is lower to accelerate at the same rate becuase it can create boost easier at a higher rpm but also the HP at higher rpm can fight the load a little better and get moving. I could go on for hours about it lol. The 15SS you've got should be a 1700-1800 stall unit which is the most popular stall and best driving stall speed but in very slow moving heavy load situations where fuel consumption per rated HP output is a factor then a looser converter can help. My build theme currently is to show you can have 4th gen performance with the 2nd gen trucks without breaking the bank, and it really does do everything a 4th gen can except initial acceleration loaded due to gearing. I can post my build sheet if your curious.

[@mattvanatti4628]

My 7.tree would pull that truck and trailer up any hill...no problem

[@Ryskyguy]

First off you’re wrong, second no one cares