Gears and transmissions and towing, oh my!

[Archive]

So here I am in Colorado, here on business for three weeks. Being the autocrosser type, I chose to drive out and tow my car. The truck is a 96 RAM 3500 CC 4x2 with automatic and 3. 54 gears. It has the TST #5 (280/680) plate centered, AFC housing all the way forward, and the 16cm2 housing. I also have the BD extra low stall converter and valvebody. Truck recently dynoed 242 hp and 617 lbs-ft at the wheels.

I carry a Lance 1030 camper and tow an '86 Corvette on an open trailer. Total GCWR on the way out was 18,060 lbs as determined by a Flying J truck scale.

My first observation is that I think I need to go to 4. 10 gears. Going up many hills, still at only half throttle in 4th, I had to let it lose speed and eventually drop into third and hold about 50-55 mph, with the RPMs at or above 2000, to keep the EGTs in check. I was still consistently holding at 1300 deg, and as the elevations got higher, it got consistantly worse.

It got to the point that while canyon-carving in eastern Utah on I-70, going DOWNHILL slightly (on the throttle, not on the brakes), the best I could do was 60 mph at 1200-1300 deg. in 4th. I could drop to third and get it a little cooler, but then I was still suck at the same speed. The road was very capable of supporting 70+ (as was the speed limit of 70-75). I just couldn't do it.

The tires are 225/70-19. 5's, so they're quite a bit taller than my stock 215/85-16's. This is part of the problem, since it's made my 3. 54 an effective 3. 23 or something like that.

Add to that the fact that the transmission is a POS. Once high enough, and with the hot weather (90+ deg), the thing didn't want to downshift below 3rd gear without flooring it or shifting manually (during stop and go traffic in Salt Lake City). Also, leaving from a standstill took absolutely forever.

I've come to the conclusion that I need one or more of the following:

- 4. 10 gears
- a conversion to a 5 or 6 speed transmission
- a Gear Vendors splitter
- a new truck

So I'm thinking... the quick and easy solution is to do 4. 10's, maybe even before I head home at the end of the month. Still, I could end up with a dead transmission by the time I get home, dunno.

If I keep the truck, I'd want to add to the 4. 10 setup a GV box, but that's like $3000 installed.

So then I wonder if that $3k (plus the $500 or so installation of the new gears) wouldn' be better spent as down payment on a 2001 ETH 6sp RAM (or, dare I suggest it, an Allison-equipped Duramax Chevy with a CREW CAB).

Thoughts?

Rob

 

[Archive]

Ok Rob... just my $. 02 -- sell the wheels to help pay for a 4:10 and a US Gear overdrive. I do feel that anyone pulling anything bigger than a lawn tractor should have bought a manual! As for the Dura-puke, none of us should care what gearbox they mate it to, the motor is a V8. During your road-trip, did you happen to see any V8-powered semi's in the truck stops? NO!! They dont work as a diesel! The new truck is a non-choice because of this.
It seems as though the manual trucks should have the 3:54, and the automatics have the 4:10. They just work better.

 

[Archive]

Rob, you asked. I tow a tall 27' 5th wheel. At least 7klbs, 3:54, 5 speed & 235's. My OD doesn't drop the RPM as much as yours & I tow just fine in 5th. The only reason to shift is real tight corners, other 5th wheels towed by 24valvers & EGT.

I'd ante up for the 4:10 gears because of your real tall tires & auto transmission. Put in the gears & take a look @ where you're at from there. I'll bet all will be tons better. I don't remember exactly how it works, but you'll sure get more torque multiplication with the 4:10's. Something like rear end torque multiplied by 3. 54 as compared to the same torque multiplied by 4:10. A bunch, anyway.

Don't forget, a freebe is sliding the plate forward. A non-stock plate in the stock position? What is BOMBing for. #ad
#ad
#ad


------------------
Money Sink - 96, 5 speed, Injectors, 280/685 & AFC housing slid.
4" CAT back & CATless, 4" chrome turn down straight out back.
ISSPRO Pillar, Delvac 1 & Amsiol, K&N, Monicas silencer ring removed, Exhaust brake, Mag-Hytec, 3:54, 235s.
HX35s days are numbered, HX40-16 is here.
Un-Bombed = Boring

[This message has been edited by Forrest (edited 08-14-2000). ]

 

[Archive]

BCFAST says:"sell the wheels to help pay for a 4:10 and a US Gear overdrive. I do feel that anyone pulling anything bigger than a lawn tractor should have bought a manual! As for the Dura-puke, none of us should care what gearbox they mate it to, the motor is a V8. During your road-trip, did you happen to see any V8-powered semi's in the truck stops? NO!! They dont work as a diesel! The new truck is a non-choice because of this.
It seems as though the manual trucks should have the 3:54, and the automatics have the 4:10. They just work better"

As for the wheels, you can simply go to a low profile 19. 5" tire and still have near the same overall diameter as your old 16's. The manual transmission is definately the way to go when pulling a heavy load long and hard. But, since you do have the auto, there are ways to make it work better for you. The 4. 10 gears would definately help. It is a relatively easy and inexpensive swap for your two wheel drive. If you got your 19. 5's from Rickson's, you could have them help you determine the proper speedo correction for your new gear/tire size setup.
You definately need to keep the Cummins, even if its in a new truck. BCGAST is exactly right... . How many big rigs do you see with V-8's on the road??? It is not as good or efficient of a design as an inline six cylinder. Getting one of those would be a step backwards as far as raw pulling durability is concerned.
I would try the gear swap first and if you need new tires, try the low profile 19. 5's. I am very happy with my 4. 10 gears and 265/70R19. 5 setup. I agree with what BCFAST said but would not recommend getting rid of the 19. 5's due to their improved handling and longer wear. Just my $. 02 #ad


------------------
1996 White, Extra-cab, 4X4, 5-speed, 4. 10 Model 80 rear, Laramie Pkg, Rickson 19. 5's w/ with Michelin 265/70 XZT's, 4" turbo-back full-straight pipe exhaust with through the bed stack, Mopar brush guard, "Psychotty Air", no silencer ring, Banks Boost & Pyro Guages 'tweaked' injector pump, 130,000+ miles
Rollin'-S 25-foot, 10 ton flatbed g/n trailer, with Vac/hyd brakes, 16. 5" tandem duals
'92 D350 Cummins, auto/OD, 3. 54, enclosed service body, 45,000 miles. unBOMBed as of now.

[This message has been edited by DieselNut6BT59 (edited 08-15-2000). ]

 

[Archive]

Originally posted by RobG:
So here I am in Colorado, here on business for three weeks. Being the autocrosser type, I chose to drive out and tow my car. The truck is a 96 RAM 3500 CC 4x2 with automatic and 3. 54 gears. It has the TST #5 (280/680) plate centered, AFC housing all the way forward, and the 16cm2 housing. I also have the BD extra low stall converter and valvebody. Truck recently dynoed 242 hp and 617 lbs-ft at the wheels.

I carry a Lance 1030 camper and tow an '86 Corvette on an open trailer. Total GCWR on the way out was 18,060 lbs as determined by a Flying J truck scale.

My first observation is that I think I need to go to 4. 10 gears. Going up many hills, still at only half throttle in 4th, I had to let it lose speed and eventually drop into third and hold about 50-55 mph, with the RPMs at or above 2000, to keep the EGTs in check. I was still consistently holding at 1300 deg, and as the elevations got higher, it got consistantly worse.

It got to the point that while canyon-carving in eastern Utah on I-70, going DOWNHILL slightly (on the throttle, not on the brakes), the best I could do was 60 mph at 1200-1300 deg. in 4th. I could drop to third and get it a little cooler, but then I was still suck at the same speed. The road was very capable of supporting 70+ (as was the speed limit of 70-75). I just couldn't do it.

The tires are 225/70-19. 5's, so they're quite a bit taller than my stock 215/85-16's. This is part of the problem, since it's made my 3. 54 an effective 3. 23 or something like that.

Add to that the fact that the transmission is a POS. Once high enough, and with the hot weather (90+ deg), the thing didn't want to downshift below 3rd gear without flooring it or shifting manually (during stop and go traffic in Salt Lake City). Also, leaving from a standstill took absolutely forever.

I've come to the conclusion that I need one or more of the following:

- 4. 10 gears
- a conversion to a 5 or 6 speed transmission
- a Gear Vendors splitter
- a new truck

So I'm thinking... the quick and easy solution is to do 4. 10's, maybe even before I head home at the end of the month. Still, I could end up with a dead transmission by the time I get home, dunno.

If I keep the truck, I'd want to add to the 4. 10 setup a GV box, but that's like $3000 installed.

So then I wonder if that $3k (plus the $500 or so installation of the new gears) wouldn' be better spent as down payment on a 2001 ETH 6sp RAM (or, dare I suggest it, an Allison-equipped Duramax Chevy with a CREW CAB).

Thoughts?

Rob

Out of curiosity, why do you have a 16CM exhaust housing, but no exhaust mods, like removing the muffler or going to a 4 incher? Next, why are you trying to run the engine so slow with that large housing? It would seem to me that you'd have difficulty getting boost (and that might explain your slow take-offs, too) at the low end, resulting in high temps and poor power. For your gears and running under 2500, you'd be far better off using the 12 (best) or 14CM (somewhat better than 16CM) wastegated housings, it seems to me.

Next, have you had your injection pump timing set to 14-15 degrees (engine) and your TDC pin verified? None of this really sounds right, especially the part about barely being able to go 60 downhill.

Changing gears will do 2 things: Increase your bottom-end torque, and make the speed difference between gears less. I'm not sure that's really going to help all that much. As long as you're in lockup, driving in a gear that doesn't lug the engine makes sense, and the final ratio doesn't have that great of an effect.

Really, I think you need some diagnostics here, not a new truck, or even spending a pile of money.

For what it's worth, that's my free advice and opinions, and it's probably worth a smidgeon less than you paid...

Mark


------------------
ICQ 3807791 (BBSMan)
Please visit Land Speed Record Pages at www.my2kcity.com/lsr
Email powerwagon@my2kcity.com
12 Valve Forum moderator and Procrastinator extraordinaire...
Tow-er '65 Power Wagon Crew Cab, Tow-ee '70 Boles Aero 28

 

[Archive]

Hey Rob are you going to the RamRunners meeting tonight? This can indeed be worked out and what a better place to do it, 30 Diesel nut giving all kinds of confusing advice. Drop me an e mail and I will tell you how to get there.

------------------
1996 4x4 3500 4. 10 5spd, Diesel Dynamics stage 2 injectors, #5 TST plate, Govoner spring kit, 16cm2 housing with 4" exhaust, Cummins exhaust brake, US Gear overdrive, Grover air horns, Mag-Hytec cover, and more.

 

[Archive]

Thanks for all the advice, it's appreciated.

Power Wagon: I agree, I think I need some diagnostics too. Just gotta find a place to do it. I have the 16cm2 housing, the stock exhaust but with the Walker muffler. I still have the cat, but would like to lose it, except I'd prefer to run a pipe through it rather than actually remove it, for the "stealth" look. I do have the #5 plate in the center position. We had it moved all the way forward, and it sent EGT's out of sight, so I moved it back to the center again. I also felt no power difference with it all the way forward. I don't get boost until I see around 1500 RPM, but I do peak around 36 psi at lockup in 4th, but only around 30 at lockup in 3rd.

Blair: Can't do the meeting, because I'm in Colorado, but I'd like to go to the next one. I'll be back in town by September 4th.

Rob