Need advice, E-locker conversion into 85'

[Erick Lihme]

Based on your experience, the crawler is on the list. I'm planning on putting all this together in fall.

Might prefer the dual case because the 4.7o gearing alone I was considering is too low for normal trail speeds, lowering the top comfortable speed down to about 10-12 mph with revs near 3000. The dual case 2.28 x 2.28 seems to be the way to go, unfortunately one should be careful not to break the truck.

 

[DaveInDenver]

Based on your experience, the crawler is on the list. I'm planning on putting all this together in fall.

Might prefer the dual case because the 4.7o gearing alone I was considering is too low for normal trail speeds, lowering the top comfortable speed down to about 10-12 mph with revs near 3000. The dual case 2.28 x 2.28 seems to be the way to go, unfortunately one should be careful not to break the truck.

You are going through the same decision process as me. I don't specifically crawl my truck, but having two lockers means I do want to see where I can go. For me an Ultimate seems like overkill when doubled down (both cases engaged). But I can see advantages to having a stock ratio low range and a second super low. I have 5.29 final axle ratios on 33" tires and so my 1st gear is pretty decently low, so I think just put in 4:1 transfer gears and be happy. But the 2.28:1 ratio is not just a coincidence. Toyota seems to have picked that ratio so that the tranny gearing has a relationship. You'll notice that 1-2-3-4-5 under normal acceleration come at pretty even intervals, around 15,25,35,45,55 MPH. When in low range, the shift points move lower, but still at regular intervals, like 5,10,15,20,25 MPH. The ultra low gearing throws a wrench in all that, so you end up going 1->3->5 and that is not a natural shift pattern for you or the tranny. So for most normal 4WD roads, having a stock low range is handy and so I keep coming back to two cases. Whether or not the second gets 2.28, 4.0, 4.7 is the hard decision. I wonder if a double stock ratio has the effect of just changing the interval to 2,4,6,8,10 MPH in low-low or not? Anyway, with both cases in low, I think you are using one particular gear, be that 1st, 2nd, whatever, to crawl and you aren't really shifting anyway. So I figure I'll do 2.28 and 4.70 and when I'm in low-low I'll just find a tranny gear that is appropriate for the task.

 

[Erick Lihme]

Yes, it is a question of how loooow will she go!

Playing with a gear calculator helps and suggests that your choice, a 2.28 x 4.70 is the way to go. With the 2.28 x 2.28 = 5.20 reduction for the most control for safety and success doesn't seem optimal. 33's with 5.29's in 1st yields 1mph at 1,100 rpms, and 2mph at 2,200 rpms.

The 2.28 x 4.70 = 10.70 reduction. With this kind of torque some recommend chaining the motor and trans down to avoid broken mounts. Go sans chains if used infrequently and especially if one is EASY on the throttle it might be useful during self recovery as: 1st yields 1mph at 2, 270 rpm, 1/2 mph at 1,100 rpm, slow enough to help the winch? In 5th, 6 mph can be attained at
2,939 rpm, and keep it out of the sand.

I'd have to agree on paper anyway, that if going with the double case, going extreme might be practical, rather than my conservative approach of 2.28 x 2.28, or 4.70 single case. The stock 2.28 cases rarely wear out, and the expense of going with that single case in lower gears may not be the best money spent. At this point the 2.28 x 4.70 combo wins.

It's good to talk it out. I'll try to read more over at the Marlin Crawler board.

 

[Erick Lihme]

http://www.4crawler.com/4x4/4R_TechInfo.shtml

The user comments on his Ultimate Crawler (2.28x 4.70) with 33's and 4.88 Diffs:

# To put this in perspective, take a typical engine idle speed of 800 RPM and using 33" tires with the above gearing, your speed is about 29 feet/minute, or less than 1/3 MPH!
# FYI: My 22RE engine will stall in lo-lo-2nd gear at idle (121:1) but will not stall in lo-lo-1st (224:1), even up a steep hill w/ brakes applied.


Not only would we have this extreme example, yet many other possible gear choices from the stock 2.28 to every thing in between....Interesting!

 

[Grim Reaper]

It's true, a locked diff (particularly full spool, like the e-locker or Air Locker) means that each wheel on the axle see exactly 50% of the torque. So you are actually /less/ likely to break stuff with a locker than with another differential, as long as you drive reasonably. Bouncing around will still shift weight disproportionally and in a geared down drivetrain that's still a lot of torque. Grim is a smart guy and no disrespect, but that's part of the reason it's bad to use 2WD-low. You will more than double (2.28x in a 4 cylinder Toyota t-case) the amount torque delivered to the driveshaft. So you are putting a lot of torque into the rear axle. There definitely lower risk with the rear locked, but I still feel it's mostly unnecessarily stressing things.

That is a double ended.

Locked both ends and making a tight turn you are putting more strain on the drive lines because you are binding across the full wheelbase and track. In my case I ran 2 low because the lock right acts like a spool and as soon as you apply power to it you have an issue with extreme UNDERSTEER.

If the trail was smooth and non technical I ran 2 low. It allowed me to make tighter turns. It put a LOT less stress on the steering (and I could over heat the powersteeing in that truck). The low range gave me better throttle control. That truck was an auto so running over 2,000 rpm got the converter fully locked. It also made the load on the engine and transmission lower so they generated less heat. My 5speed 4Banger I regularly put around at 1000 RPM and it pulls just fine for most stuff. Just cant do that with most Auto tranny's

Yes it put more stress on the rear axle but in trail conditions it was nowhere near the stress that axle saw on pavement where I didn't drive in 4wd either. With the Detroit as soon as you got on the gas you were a Spool. The only way to unlock it is to basically coast through tight turns. I could steer the truck on the hwy with the gas peddle. The more gas you applied the straighter the truck would go despite the steering input.

After the ill handling issues I had on the street I decided that a selectable locker was mandatory in my next rig (my current 4Runner) and why It now has the e-locker. Max traction off road and great manners on the street. Best of both worlds.

 

[DaveInDenver]

Locked both ends and making a tight turn you are putting more strain on the drive lines because you are binding across the full wheelbase and track.

True point, without a selectable front locker that would be a very valid issue. That's why IMHO the front of most (i.e., non-hard core rock hounds) 4WD vehicles should be left open unless the locker is selectable. An auto front locker would reduce stress on the driveline straight ahead, but be brutal on the steering and like you say, binding would be a problem.