1320

I was told once, dont know by who, that it wasnt good dea to tow in 6th. That 6th gear in the nv5600 has a history of failure while towing in 6th. Any foundation to this? I run amsoil, two pto cover coolers, but the truck makes good power. With 3.54 gears (12 valver ,converted) I can pull in 6th at pretty high speeds, pretty easy. Even slight grades can be pulled at 75 mph with gcvw in the 25k+ area. 6% grades are 5th gear at 66 mph.

Any history of nv5600 failure towing heavy in 6th?

I could/have thought about going to 19.5's and then I could tow in 5th all the time due to the taller tire, and just use 6th on the flats at lower rpm. The miliege might go up and its not bad now at all.

RAMRODD

I pull up to 42K in 6th all the time with 22.5's. And about the only time I unhook the trailer is to grease.
Everyone I know pulls in 6th

radshooter

I pull our 17k fiver in 6th if it is flat or slightly downhill. I watch my RPMs. If they start to drop below 1800, I go to 5th gear. If I am in hilly country, I just leave it in 5th and run 2500-2600 RPMs all day long. I only run 60-65 MPH though. Still running the stock 17" tires too.

1320

your sig.....says proud member of the broke nv5600 club? LOL...how did that happen?

Casey Balvert

You are probably thinking of the old NV4500 that used to lose fifth gear from lugging at low speeds. I have towed thousands of miles in sixth without a problem.

RAMRODD

Foot slipped off the clutch in 1st gear I had a goosenect trailer hooked up with 450 bushels of corn. Cracked the case which caused a bearing to spin.

Mr. Big Ram

... if you remember, when I broke my "first" 5600, I was in 6th, not sure if that was the actual problem or not at the time. Did you hurt yours or something?

12PACK

That's what I was thinking. The 5th gear nut issue affected for than one truck.

1320

No I just dont want to. The dam thing cost $3000 so I dont want to do anything hat might be more harmful then something else I could do. Since I coated the housing , installed the ported and coated ats mainifold, its pulling incredible. I hate to say it, but its easy to go too fast. It wll pull at 75-85 easy.

Cool, I guess I wont think about it anymore, now I can just worry about melting tires when the heat comes.

Bark

I always tow in 6th unless (as radshooter said) the rpms drop.

Equalizer 2

I just finished a 600 mile trip today. The speed limit determined whether I used 5th or 6th gear. Anything over 55 mph I used 6th unless I hit a hill then I dropped to 5th to keep the RPM up and the EGTs down. I am still running the OEM tires and wheels.

I don't know if you could call 19,000 GCVW heavy but that is what I am running.

biglar

I think mine's an unusual case, but at about 97,000 miles my 2nd clutch (SB) started slipping, and when the shop pulled the trans found that the input was badly galled. Fine, fix it, but when they opened the tranny found that 6th gear had about ½ tooth broken off. OK, fix that, too, since it's out of the truck. I don't remember grinding or clanging or crunching, but it was surely broke.

About 10,000 miles later I was towing a light (2,500 lb) trailer across flat desert in SoCal at 65 mph in 6th and was kicked back with cruise control on. Suddenly the engine rev'ed, cruise control kicked out and I started slowing down. Long story short, all gears worked fine except 6th. Towed it the rest of the way to Santa Fe, NM at 60 mph in 5th, then had a shop tear it down. The large diameter spot welded gear on 6th had broken loose from the rest and was just spinning.

That was about 15,000 miles ago, and I'm uneasy with heavy loads in 6th now.

Worth what ya paid fer it. Lar.

oilfield-trash

Took one to Oklahoma City in 6th gear and brought one back in 6th gear. Thats was 50,000 miles ago. Motor was a tad over 15,000 lbs.

Tow how you like.

NavyChief

Look in my photos and you will see the load I pulled from Va to Oh when I retired from the service. The trailer and two tractors was close to 21K and unless I hit a good grade, I stayed in sixth. The truck towed awesome and no issues to report!!!

Regards

Eric

Valv

Is that your engine replacement or what ? You won't be driving a Cummins anymore....

I towed in 6th all the times but I still think it's safer to do it in 5th when rpms are 1400 or below