I recently bought a older 5.9 diesel. It pulls okay and not bad miliage. But my problem is while towing a enclosed trailer and the overdrive off I can only reach 55 or 60 mph. Empty I have no problems reaching 75 pmh. Any advive out there or is it just worn out?

Worn out? Unlikely!

what year? all Cummins 5.9 rams have enormous power producing potential but the earliest ones weren't exactly powerhouses, stock(160hp iirc) but the good news is that lots more is available. tell me what you've got and I'll give you some options. this same basic motor went from 160/420 to 325/600 over the years.....

Dave

Its a 94 with auto tranny 208K miles on it in a 1 ton

One of the best websites for Cummins info.

http://www.dieseltruckresource.com/dev/

why would you be towing with the OD off

I seem to remember my old Ramcharger owner's manual stating to not tow with the OD. I think the torque capacity of the OD planetaries is limited (torque multiplication going the wrong way). That was my theory anyway.

I dont have the owners manual for this one.But i know on my gas engine truck it says not to tow with the
OD on. Am i wrong in thinking the same for the diesel?

Check to see if you get full travel on the throttle linkage, also you might want to do a few quick mods to get a little more boost and fuel. Very easy to do with the p-pump engine. I would recommend egt and boost gauges. No worries towing in OD, the 47RH is a good transmission, im putting 550hp and 1350 lb/ft tq through my 47re and im running stock clutches in it.

Also check to make sure the fuel shutdown solenoid is opening fully. The one on my '96 was misadjusted from new and while it would rev to 2,500 RPM, it didn't make any additional power from 2,000 RPM up as it should have.

Robert

hi,

well get under your truck when the engine is warm and idling and see if you are getting any blow by out the breather .

none to a small amount and no problem in that engine !

mine has some blow by and i tow 45 miles one way to the local track with trailer and car 6000 + truck weight 98 ext cab 8' bed 2500 300,000 miles!
up and down steep grades ,and i use od if traffic is moving fast enough as i only have 3.55 gears . you could install a transgo tfod-diesel shift kit to greatly extend trany life !
+4 fluid only .

some simple adjustments and you will be able to pull at any speed .

Thanks for the ideas everyone.Im going to crawl around it today and check it all out. Hopefully ill find something not to difficult.
I will post if i find anything or not.

You can tow in OD, just don't lug it.
In Ohio, there are many diesel shops who can FIX the power problem. But you need to add a Pyrometer and boost gauge before.
I had a 95 touched up and it would run 95 in the quarter mile.
More fuel and more air is what you need.
But you need to make sure the trans can handle the power and it won't in stock condition.

Your truck is fine. There are no problems with it.
The engine governor on the early trucks is set at 2400 rpm. Without OD and using 3.54 gears mine redlines at 60 mph.
With OD off, I run 60 mph in the 1/8 and 62-63 mph in the quarter.
With OD on the truck will run 95 mph. It just doesn't have the rpm to go any faster.

I always tow in OD with mine. 273,000 miles and still going.

Kevin, from his original post, he says he can get to 75 MPH unloaded, 60 MPH loaded, sounds to me like he's running out of power in the upper range, 2,000 ~ 2,500 RPM? He also hasn't mentioned what size tires he's running.

Robert

assuming it's running correctly (which is possible as they weren't exactly powerhouses in 94) I second the recommendation for boost and egt gauges. a set of injectors would help power and there are lots of mods for the P7100 equipped motors. I recommend the TDR for more info www.turbodieselregister.com

the 47re is weak with additional power. www.dieseltrans.com

good luck
Dave

I changed the fuel filter and cleaned out thescreen today. the tires are the factory size.The filter did have some junk in it, But dont think that was thetotal problem. Ill try it out tomorrow and find out. Thanks for all the suggestions. If i cant figure it out there is a shop here in town that races a diesel.Maybe i can get them to look at it without charging a arm and a leg. lol

BTW, it has a 47rh trans.
To wake it up a governor sprink kit needs to be installed with a fuel plate. Depending on what plate is used a turbo change may be needed.