Towing in 5th Gear

[DThiel]

I have a '99 3/4 ton, 4x4, 5 spd. with 3. 54 gears. I tow a 28 ft. fifth wheel that weighs approximately 7,000 lb. s loaded (I haven't wieghed the truck and trailer yet).



I am wondering if my truck's performance while towing is typical or if I need to get it checked out.



If I am towing in 5th gear at anything less than 2000 rpm, I cannot maintain speed with even the most moderate hills. I live in Minnesota - we don't have much for mountains around here! If I keep it above 2100 rpm, the rpm's won't drop and it will pull like there isn't a trailer behind it.



I realize that 3. 54 gears aren't the best for towing and that upgrading to 265/75 tires didn't help the gearing, but is this normal performance? A 7000 lb. trailer doesn't seem near as heavy as what a lot of you are pulling. Is part of the problem wind resistance? The front of the camper isn't as high as new units, but it isn't sloped back like newer models.



I've done a quick check of the clamps on the intercooler hoses and they seem tight. Would a bad lift pump cause poor performance below 2000 rpm? Am I just expecting too much when pulling in 5th gear?



Any input would be appreciated.

 

[JAK]

The 24 valve likes to run at or above 2000. Mine doesn't really come alive in a hard acceleration until the tach passes 2k then it goes like mad. I don't tow in 5th gear unless I'm driving fast enough to keep it around 2000 rpm. (I also don't want to loose the 5th gear nut)

 

[klenger]

I noticed the same thing pulling my 10,000 5er with a 2001. 5 5 speed 3. 54. Traded for a new truck (see sig).



I would recommend keeping it in 4th and run it at about 65 MPH. I think that your RPM's will be around 2400.



Ken

 

[JohnB]

I really have no problem pulling my 9000lb trailer in 5th gear at anything above 1700 rpm. Without the EZ it would still pull, just not as hard. Normal grades were fine at anything above 60 mph which is about 1850 rpm. The larger tires will make your situation worse.

 

[time1]

I have a similar truck. A 99 quad cab with 3. 54 gears, 5 speed, and 265 tires. The truck is total stock except for the rims and tires. Also have a 28 foot 5th wheel that weighs about 7000 loaded for short trips. No problems pulling in 5th gear. I try to never let it get below about 1750 rpm in 5th(two marks above 1500). Mine runs real nice at 1900 rpm which is about 65 mph (14 to 16 mpg).



You know, DC could change the Tach markings. Each mark seems to be 125 rmp. So when you start at 1000 rmp the marks are 1125, 1250, 1375, 1500, 1625, 170, 1875, 2000. I wonder just how hard it could be for DC to remark the dial and make 10 divisions between the thousand marks?

 

[DHatfield]

My truck pulls my 6000 lbs of trailer up hills in 6th gear without any problems even when stock as long as I keep the RPM's about 1700 - 1800.

 

[Fast 1]

Hi D Thiel, Here's my imput. Is this performance typical for a 99 3/4 ton 4x4, 5-speed, with 3. 54's and 265/75 tires. Yes this is somewhat typical for a stock truck with that set up. The gears and the tires combined bog it down a little. I'm not sure if your truck is stock or not ?



Are you expecting too much when pulling in fifth gear. Maybe with a stock truck. Add some gauges, then add a fueling box like a EZ Edge or injectors. And then add Fast Coolers for your 5 speed. The EZ edge will give it grunt to pull in 5th. And the Fast Coolers will keep 5th cool when towing. Forth stays cool when towing because of a 1 to 1 ratio ( direct) . But 5th gear will heat up within 30 minutes when towing because of a 1 to . 76 ratio change and the torque that is being applied to it from the mighty cummins turbo diesel. This is just what your truck may need.



I hope I have accurately addresed the questions you had.



www.fastcoolers.com



Verlyn R. Fast

 

[BigMike]

See my signature. I pull my 10500lb fiver in 5th gear all the time. Drop to 4th when she gets under 1750 RPM's. Drives like a dream!

 

[FFutch]

don't drop a nut

From what I've read on here you don't want to run under 1800-1900r. p. m. s in 5th. Something about strain on 5th gear nut. Any more I don't chance it,when I get to 2000 I start looking to shift. Would rather pay a little more for fuel vs. fixing a gearbox. Of course alittle BOMBing always helps Doug.

 

[SClegg]

I have a 27' 5vr wieghs about 8000 and I pull in 5th most of the time. I live in Colorado and when I pull in the mountains I pull most of the time in 4th. I use the cruise most of the time, but if the pedal is to the floor on cruise, I down shift into 4th until it starts excelerating on the hill. I read somewhere that when pulling a hill you should be in a gear that would allow you to accelerate on it. I do that and could not be any happier. I especially liked last week end when I was running up I-70 above 10,000 ft. and was passing every other vehicle on the road. Finally had to slow down at the tunnel for other traffic. I usually run at 2000 rpm when in 5th. If I am in 4th I still try to maintain about 65 MPH, which in my truck is about 2400 rpm.

 

[JJW_ND]

Dthiel:



If your truck has never had any computer flash updates, you might want to consider it. We have several 99s, 2000 and now 4 new HO 6sp. All 3. 54. should be able to run in 5th all day here on our flat country. Our trucks are all stock. Broke in pulling hard.



jjw

ND

 

[nopowerforme]

I have a 95 2500 with the 5 spd and tow a 33ft 5er 12,600 lbs 3:54 I have added The TST upgrade and tow even up grades in 5th gear.



Have more than enough towing power . Am now in Intl MN and have towed to FL. Mass. MS MN ID and through many other states. I have the Jacobs exhaust brake and tubo and boost gauges. Like he said a little bombing goes a long way

 

[Wiredawg]

I Tow in 6th Gear

Hey Y'all:



I tow my 15K Lb 5th wheel in 6th gear most of the time and no problems. Just came back from TX towing and ran great on the hills. I even shut off TST PM-3 (level-6) to see how she pulled with just the 275 RV injectors and she pulled pretty darned good. Still, it pulls way better with PM-3 turned on.



Wiredawg