Take off in 4-low when pulling heavy?

[AcIdBuRn02ZTS]

Hey guys..

Well I'm trying to decide on getting an auxiliary underdrive unit or taking off in low range when pulling heavy loads. Truck has 4.10s and 37" rubber and I don't want to have to slip the clutch to get it moving when heavy.

I'd heard several people talk about taking off in 4 low and shifting into 4 high once rolling... is that safe for the t-case?

What other options (besides re-gear or smaller tires) would I have? The most I'd ever have behind this truck would be 15k or so.

 

[chris142]

I often use 4lo when backing a trailer. My 3.55 gearing is too fast.

 

[shawn deere]

I love 4 low. But am also interested in shifting on the fly. I dont. My dad does. It makes a hell of a clunk at times.

 

[79jasper]

Someone here does it, I just don't remember who.

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[Clb]

It'$$$ your money!
Under drive or stock rubber.
I use 4lo in camp and for detailed work all the time.
I doubt Spicer would approve of the shift gate trauma most likely possible with missing the detent.

 

[IDIBRONCO]

I do like Chris does. I even did the same with my Bronco which had 4.10s.

 

[BrianX128]

Do you have manual locking hubs? You definitely wanna make sure you leave them unlocked in case your taking off on a turn.

I've done this in my winter beater f250 with a Mazda 5 speed manual, bw1345 and a 300 straight six [not a power house obviously. I pull out in second gear in low range and rev it to 4k, and quickly jam it into high range or 2 wheel high and leave it second gear or if it's a real steep grade and I'm not gonna lose momentum I'll throw the trans in first.

Problem is anything over 5mph and the transfer case gets real mad. I've tried double clutching it and various things and nothing makes the transfer case much happier.

 

[FarmerFrank]

Must be a regional this Brian.

My beater 300 4 speed truck I'll run it out in 4 low (if I really need it) and jump from 3rd Lo to 2nd Hi and never miss a beat on it.

Have you ever driven a double club Mack? Hi-Lo shifts are ALMOST as fun as driving them.


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[DaveBen]

The transfer case is NOT connected to the clutch. It is driven by the transmission output shaft or the driveshaft, so it will grind no matter how you try to shift it. I never shift faster than walking speed.

 

[hoodshauler]

Not a good idea IMO To use 4 low then shift to high on the fly
You should be able to get 15k rolling without slipping the clutch.
Underdrive would be my choice if I was going to do anything


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[Shadetreemechanic]

I use 4 low to get going when heavy often, but have never tried to shift out of it on the fly. Remember you can roll through all your gears in low range. I just find a spot where it is level or down hill, put it in high range and off you go. I have 3.55s, a zf-42 and have many times had WAAYYY more than legal behind my truck and have never had a problem getting going this way. The 1356 is not designed to go from low to high while moving.

 

[no mufflers]

Heath has an under drive unit. Maybe someone can tag him?

 

[Macrobb]

With stock rubber, I've never had trouble starting in 1st. A little slipping for a second or two, if that, and engage it. Rev it up to redline, and get it into second.
That's what I did when hauling about 14,000lbs. Didn't have any issues with that, except for having to go 45 up hills for the first 20 miles before I realized my emergency brakes were on... And not going over about 55-58 due to it being a bumper-pull trailer with no load-leveler or anti-sway protection.

I'd say just go back to stock(or close) diameter wheels; the extra rubber is more expensive anyway, and it doesn't help when hauling.

'Course, if you need, you can always keep a spare set of wheels and tires. Swap on the smaller ones when you need to haul a massive load, and use your larger ones otherwise.

 

[chris142]

[QUOTE="FarmerFrank,

Have you ever driven a double club Mack? Hi-Lo shifts are ALMOST as fun as driving them.


Sent from my iPhone using Tapatalk[/QUOTE] no but I did own a petetbilt with a 5speed main and 3 speed auxilary...I liked it better than an air shift trans

 

[compressionignitionrules]

I use 4 low to get going when heavy often, but have never tried to shift out of it on the fly. Remember you can roll through all your gears in low range. I just find a spot where it is level or down hill, put it in high range and off you go. I have 3.55s, a zf-42 and have many times had WAAYYY more than legal behind my truck and have never had a problem getting going this way. The 1356 is not designed to go from low to high while moving.

agreed with this 100% Tcase is not "shift on the fly"!