Transfer Case performance

[Stkelsey]

I'm still learning my way around my M715 and I'm unsure of what to expect from the High and Low range of the transfer case. I've correctly adjusted the travel on the lever arms for both Hi-Lo and 2W-4W drive so that I can shift between selections. I've verified that I can switch between 2W and 4W, but it seems like I'm in low range all the time. I top out at about 40MPH in 4th, transfer case whining hard. If I back off to 35, it seems that I've reached the safe and safe sounding top end. I have yet to tear into the transfer case but wanted to know if the posted top end of 60 in Hi Range is downhill with a wind behind my back? I thought that it should be possible to reach 50MPH and at least travel some 'main' roads, 35MPH kind of precludes that. Thanks in Advance.

[Barrman]

Low range is only 1.98:1 or so. Which means it isn't that noticable at lower speeds that you are in low. Sure, it is half as fast, but unless you drive the truck a bunch, you won't notice the difference right off. The max speed for low/4th gear on the dash data plate is 35 mph. So, it is possible to go that fast and not blow things up.

If you still have the stock t-case shifters, you can not be in low 2wd. Therefore, if you were in 2wd, you were in hi gear.

The best way to check besides nosing the truck up to something un moveable and seeing which tires spin, is to have somebody move the shifters while you look at the t-case underneath. You could also mark out 100 yards or so, put the levers in what you think is hi or low, put the transmission in 1st, let the clutch out and keep both feet flat on the floor. Time your run. turn around, but the lever in the other t-case position and repeat. One or the other should take almost twice as long to travel. If not, then you are correct about being stuck in one of the two choices.

Now, the NP200 t-case is very noisy. If you can still hear the engine at 50 mph over the whine, you have a quiet one matter of fact or no muffler.

[Binford]

Welcome aboard, Stkelsey! We've got a member in Scappoose, Canby and another even closer to you I think (Kevins).

Be sure to check in on the "Pacific Northwet Regional FE" board. Some of us locals are going to be getting together at the Tillamook State Forest September 14-16.

As for your t'case performance questions, my guess is that the low gearing is getting things spinning faster for you than you're used to, and with the noisy t'case our trucks have adding to the confusion. They get howling pretty good at about 50, but should get up to 50 without really sounding like it's about to explode!

First make sure your t'case control levers are like this:




See how the forward lever cannot be moved back unless the rearward one is first moved back (because of the bend in the forward one)? The rearward one is the 2WD-4WD lever. Once that is moved back (to 4WD), then the forward lever (Hi-Lo) can come back (to Lo).

[Binford]

And here's a shot of the levers in 4WD/Low (in my truck this time).



The levers are back quite a bit more than above.

Hope this helps!

[Stkelsey]

Thanks! I'll try your suggestion! I appreciate the quick comments from both Barrman and Binford. It would appear from the very clear pictures posted that I am indeed in 2W HI range. I didn't think it was possible to be in 2W Lo, and now it's confirmed. The truck is VERY stock, engine, T case, etc, in fact I think the only non stock item is a 12V fuel pump. I'll take it out tonight and try to wind it up to 50MPH, after doing the 100 yard dash test. Thanks again! I'm sure I'll have more "newbie" questions as things roll forward.

[Loope]

Another thought... The stock tires are about 35" diameter. If yours are much smaller, that will obviously contribute to lower speeds. 3000 RPM should be about 53 mph in a stock truck.

[MarknessMonster]

And here's a shot of the levers in 4WD/Low (in my truck this time).

Hey Binford...why don't you use that truck a little and get some dirt on it for a change...JC.

[Binford]

Heh, heh, heh... That was the interior shot I took for my insurance company. That's why it was so purty.

[MarknessMonster]

That was the interior shot I took for my insurance company. That's why it was so purty.

Yeah, sure...I'm thinking that you got yourself a trailer queen once Fisherman put a coat of O.D. on it.

[fisherman]

No Tim uses his truck, Mine will be a trailer queen.