So I read something in a post today that I would like to know the answer to. I read that if you run in 4 wheel high at around 15mph for extended periods of time your tranny will overheat. I know this for a fact, because it has happened to me on the beach twice. I have since added an aux transmission cooler. I thought that may fix the problem, but the post I was reading today stated the cause for this was due to the torque converter not kicking in until you reached 3rd gear in 4 wheel high. The recommendation was to run in 4 wheel lo to avoid this. Is this accurate? Should i be in 4 wheel low when riding at the beach. I always assumed i would only use 4 wheel low if i got in a tough situation. Is it OK to run 15 mph in 4 wheel Low for extended periods of time.

Anybody have any knowledge on this subject.

 

Not 100% sure why you would go to 4 low on the beach or in a tough situation. 4lo adds more torque and pulling power, a.k.a. climbing. For instance, you get into a little mud, 4 lo will not allow you to spin the wheels fast enought to clear the tread on the tires to get grip. This is where I us 4 hi. The reason your trans is over heating is the lack of air flow that is coming through. I don't see how going to 4 low is going to be any different since your trans acts the same, it is your transfer case that shifts into the lower gear.

 

I can tell you from personal experience that your tranny will overheat. First I could smell it then the "HOT OIL" light was flashing and a loud noise following. I have since aired down to 18psi and always run in 4-lo. While in 4-lo it doesnt allow the torque converter to over heat the tranny. You can run at 15mph if the terrain allows just dont push it much beyond that as it could hurt the tranny.

 

I can't agree with this... I run in 4Lo on the beach, mud and throughout the entire obstacle that I frequent. Your wheels spin fast enough in 4Lo to clear mud and it actually seems that it takes a lot less throttle to do so in 4Lo than in 4H... Also, for a manual, your better off in 4Lo while going through mud because of the water. In 4Lo, no clutch is needed to start your vehicle so you don't have to worry about mud or water getting in the clutch...

 

I can see where it would benefit for a manual. IMO I don't use 4lo unless I need the added torque and power. Wheeling in sand or in mud I stick it in 4Hi and it leans the tires alot better.

 

i run mine in 4 lo on trails and also manual shift trans crawl in manual first climb in manual 2 if on beach in 4 high i would be man 2 mostly this applies an extra clutch pack in manual low for more holding power these gears also keep the trans from shuttle shifting {bounceing 2-3-2-3-4-3-2} every time it shifts it creates some heat i rebuild transmissions for a liveing and have been doing it for 25 yrs also a cooler is a great move try to buy one with a stacked plate design such as a tru-cool brand some coolers are no more than a tube with fins on the outside and dont provide enough surface area for the heat to dissapate hope this helps

 

I forget about the Auto/man trans sometimes... It just seems like my tranny struggles to much if I run 4H on the beach.....

 

I run 4lo when wheeling all the time only use 4hi in snow on the pavment. Never have a problem.

 

same here,

It reduces load on the transmission and engine, doesn't matter if you are auto or manual its not good to load up the clutch or torque converter with too much load.

I used to run 4lo and 3rd gear in sand in my old TJ Rubi with 33s and 4.10 always gave me plenty of power and torque.

 

I don't run in 4 low unless I need the extra torque to get over a tough spot. If is an easy trail, I don't even use four wheel drive. If I hit snow or lots of mud, I use four high and only shift to four low when I need it.

If I am running 15 mph or more, most of the time I am not even in four wheel drive.

-John