I have a problem I have a 2001 Dodge Ram 2500 24v three-quarter ton long bed 5 speed 4 wheel drive and the RPMs and everything worked perfectly fine until about 5th gear it starts surging between 65 and 70 miles an hour and I'm trying to find out why

Edited July 8, 20187 yr by Nathans24v

Time to test for alternator noise problems. Manuals are not excluded from this issue. 

 

 

Welcome. The above is a great place to start.

Any codes?  how about your fuel pressure, do you have a way to monitor this in the cab?

 

Are there any mods done to your truck?

No codes. Havent bought any gauges yet. Plan on getting some boost, fuel don't know about the third one yet.

Only thing I've done is change the hx 35 for a hx 40. But I'm about to change that cause the exhaust housing is too big and laggy on shifts.

Edited July 10, 20187 yr by JAG1

I would be interested to know what your fuel pressure is doing.  Do you have a stock lift pump?

 

Are you checking codes with the key trick or using a type of code reader?  If it is the key trick, I would look into a code reader to verify that there are no codes. 

 

Testing for AC noise like suggested above is quick and easy.

Key trick. I don't have the bosh lift pump. I have a spectra lift pump

I am going to a friend's shop that has a coder reader

Are you confusing a Bosch injection pump with the lift pump? They are two separate parts on the fuel system. The lift pump keeps the injection pump fed. Sometimes called the fuel transfer pump, it can go out, but the truck still runs because the injection pump can pull enough fuel on its own, This eventually kills the injection pump by starvation, not having enough fuel pressure to lube and keep it cool. Any fuel pressure under 14 p.s.i causes an accelerated wear or damage to the injection pump. 

 

First item is to get a fuel pressure gauge and a 1/2 inch fuel line kit with a good lift pump.  

 

BTW, Welcome to the forum.... all great folks around these parts 

Edited July 10, 20187 yr by JAG1

Fuel pressure gauge is a must in these trucks.  this will help immensely in troubleshooting and prevention of future failures.  Also, how many miles on the truck?