Author Topic: Do's and dont's with duals.. (Read 4879 times)

phatim · « **on:** Dec 11, 2011, 06:58:12 PM »

Just installed my duals in my 85. I am new to the dual tcase thing. Is there any combo that will damage the tcases ? ie: front case low / rear case high ? Any info would be great. thanks Tim

Quick Draw · « **Reply #1 on:** Dec 11, 2011, 07:11:00 PM »

No. High/Low, Low/High, Low/Low, High/High... Doesn't matter.

Yota87Truck · « **Reply #2 on:** Dec 12, 2011, 07:38:27 AM »

They are 2 separate units. Its like the difference between the transmission and the stock t case. Dosen't matter 1-5/R or 2wd/4wd or hi/low. Now you just have 3 separate units instead of 2...

Volcom · « **Reply #3 on:** Dec 12, 2011, 09:10:27 AM »

Never coast while in double low, you'll blow up the clutch disc.

possume22 · « **Reply #4 on:** Dec 12, 2011, 09:22:05 AM »

Never coast while in double low, you'll blow up the clutch disc.

??what

Sparkplug · « **Reply #5 on:** Dec 12, 2011, 09:24:52 AM »

crusing down hill coating in gear, spins the clutch at a crazy speed. I was doing it yesterday though.

If it can be avoided, and you arent using both cases, you should only use the rear case. If you use the front and no the rear, your putting the reductuion through 2 cases when it only needs to got hroyugh 1. Make sense?

Volcom · « **Reply #6 on:** Dec 12, 2011, 11:57:18 AM »

Quote from: possume22 on Dec 12, 2011, 09:22:05 AM

??what

On my rig with 39" tall tires, dual cases with 4.7's in the rear case, 1st gear at 5000rpm, total speed is 2.59 mph. Take that figure and think about coasting down a hill at 10mph. Your engine speed would be 19300 rpm at 10mph. That's way too much for the clutch disc to handle. At half that speed (5mph), the disc makes a crazy zipping noise.

phatim · « **Reply #7 on:** Dec 12, 2011, 12:09:29 PM »

Thanks for the info ! Got my duals in this weekend. Waiting on driveshafts. Really appreciate it..

phatim · « **Reply #8 on:** Dec 12, 2011, 12:15:15 PM »

So. im running 4.7s in the rear case. Not a good idea to use just the front case. As in coasting you mean, rolling in nuetral? I would be using double low strictly for crawling, or descending ? No need to use for anything else correct ? Im sorry if I sound ignorant... just trying to get as much info as possible.. Thanks in advance..

yotatough · « **Reply #9 on:** Dec 12, 2011, 04:33:37 PM »

what they mean is if you are gonna coast, pull the tranny into neutral and then coast, dont just step on the clutch, doing so will cause the clutch to get over spun and fail.

79coyotefrg · « **Reply #10 on:** Dec 12, 2011, 06:53:26 PM »

never coast down hill, your brakes wont hold near as well as your gears.

Rocksurfer · « **Reply #11 on:** Dec 13, 2011, 01:17:48 AM »

Quote from: yotatough on Dec 12, 2011, 04:33:37 PM

what they mean is if you are gonna coast, pull the tranny into neutral and then coast, dont just step on the clutch, doing so will cause the clutch to get over spun and fail.

Negative!!! Never ever put it in neutral downhill and rely on the brakes, just don't coast give it some gas you can't go fast anyways even if you floored it. Also even though you've already installed them never put the 4.7 ahead of the 2.28 always put the 4.7 at the back or you will break or twist the 2.28's shaft.

phatim · « **Reply #12 on:** Dec 13, 2011, 12:21:36 PM »

I did install the 4.7s in the rear case...

yotatough · « **Reply #13 on:** Dec 13, 2011, 01:45:50 PM »

You obviously didn't understand my post. I'm not saying to coast down hills, I said if yor going to coast, not to just step on the clutch, but to put it in neutral. Reread my post.

4RunnerChevy · « **Reply #14 on:** Dec 13, 2011, 05:17:06 PM »

Quote from: yotatough on Dec 13, 2011, 01:45:50 PM

You obviously didn't understand my post. I'm not saying to coast down hills, I said if yor going to coast, not to just step on the clutch, but to put it in neutral. Reread my post.

I think what RS is saying, is that you never rely on brakes when your wheeling, that is why you invested in all those gear possibilities. Its also good advice.

phatim · « **Reply #15 on:** Dec 13, 2011, 08:44:00 PM »

No I understood it. Thanks for the information. Really appreciate it...

Rocksurfer · « **Reply #16 on:** Dec 13, 2011, 10:38:06 PM »

As did I, and 4RunnerChevy is correct. What else would you expect to happen if you depress the clutch under the torque load doubles generate. BOOM! And who needs a clutch at that speed anyways?

yotatough · « **Reply #17 on:** Dec 14, 2011, 11:34:26 AM »

Quote from: Rocksurfer on Dec 13, 2011, 10:38:06 PM

As did I, and 4RunnerChevy is correct. What else would you expect to happen if you depress the clutch under the torque load doubles generate. BOOM! And who needs a clutch at that speed anyways?

OK. I was just trying to clarify that I was not suggesting a driving style to him, just that if he was going to coast, to do it the proper way to avoid clutch damage.

just clarifying

Quick Draw · « **Reply #18 on:** Dec 14, 2011, 04:59:47 PM »

I had a pilot and throwout bearing fail with only a few thousand miles on them. Come to think of it, it was probably because I coasted down a hill in double low. I know that I had done that a couple of times in the months between the new clutch and new clutch #2.

tyes · « **Reply #19 on:** Dec 20, 2011, 09:40:50 PM »

so whats the trick to going down a rocky steep hill without using brakes? 1st gear + Nuetral (case1) + 4Lo (case2)... please help clarify??

Rocksurfer · « **Reply #20 on:** Dec 20, 2011, 09:57:40 PM »

Never put anything in neutral, I think what everyone is saying is that if you are in double low and have a load on the drivetrain do not depress the clutch it will go boom. Pick a gear and speed you are comfortable with and just crawl it if that's what is needed. Out of all the things that you do, don't take a chance on putting anything in neutral. I have an auto and that is scary enough at times going downhill since the perfect speed to descend puts my torque converter in stall which is almost as bad as neutral. The one thing I've always said though is when wheeling and you have a concern don't hesitate to ask someone that has either just done it, has done it before or has done that type of technical trail before. Once you get a feel for your truck and its capabilities someone may lean on you for that type of info. Let the gears do their job.

tyes · « **Reply #21 on:** Dec 21, 2011, 05:04:18 PM »

can u post some example when there are do's and don't?? i thought going duals is to go slow. so, going slow down a hill at DOUBLE low would be best, i think... or shall i go DOUBLE high? im confuse.

Sparkplug · « **Reply #22 on:** Dec 21, 2011, 05:34:38 PM »

if the tranny is in 1st, clutch out, and you go down hill, your coasting, rpms at like 3k, your moving slow, all of a sudden you push in clutch, truck rolls to 10mph, but the dline is still spinning your trans in 1st gear dbl low, which at 10 mph is prob 20k rpms, make sense? Its fine to coast downhill in gear if the clutch is out. Its not safe, but its ok on the drivetrain, to coast downhill with the transmission in neutral.

79coyotefrg · « **Reply #23 on:** Dec 21, 2011, 06:53:15 PM »

Quote from: tyes on Dec 20, 2011, 09:40:50 PM

so whats the trick to going down a rocky steep hill without using brakes? 1st gear + Nuetral (case1) + 4Lo (case2)... please help clarify??

trans in 1st, crawl box in low, tcase in low, foot on the floor not the pedals.

OldGold3VZE · « **Reply #24 on:** Jan 24, 2012, 08:45:00 PM »

Just don't drop clutch in double low 1st gear and you'll be fine. There is no right or wrong, just don't want to blow up a clutch. I've seen it happen once on the trail, and it was a worn out clutch from running 35s with 4.10 gears around town too much. And remember, the clutch pedal should either be in or out, no half way. Being in gear is always the best. I love dual stock cases, but some feel they need lower, so throw in a 4.7 rear case gearset.

AX10TOY · « **Reply #25 on:** Feb 13, 2012, 06:40:31 PM »

This is great info nobody new to rock crawling or to dual case ever gets this much good advice.
My duals are on the way and can't wait to feel the way my rig crawl's over everything

phatim [OP]

phatim [OP]

phatim [OP]

phatim [OP]

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