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- 2,627
- Location
- Dekalb, IL 60115
Well, I got the rc4me center diff trans. On my bench, I'm not sure how other guys have installed it. A few things differ that I need to deal with before moving forward with it. I got it for the sole purpose of trying to help my diffs last longer. Even running 4S, I still have busted 3 or 4 diffs on bad rear or front end landings. Hopefully this will help in those situations.
The first issue, the input shaft isn't keyed to the hex washer like the stock input shaft. So, if the slipper slips, an unkey'd washer is going to be likely to spin with the spur and not the shaft which will be prone to cause the slipper to adjust itself on the fly if/when it slips. I used the original flux shaft in it's place.
The second, the gear ratio is different. I'm not smart enough to figure out which way it's different, just that it's different.
The stock flux hp trans I have has the following:
2 gear input, 18/23. The smaller of the two being used. 18 -> 44, the 44 is on the same shaft as the next gear, 33 which spins the output 29.
RC4Me trans:
1 gear input, 21. Spins gear 41 which is on the same shaft as the next gear, 31, which spins the output gear/diff 30.
I'm not sure if this math is right:
stock
18-44 32-29
18/44=.409
32/29=1.103
.409*1.103= .45
rc4me
21-41 31-30
21/41=.512
31/30=1.033
.512*1.033= .53
If that's the case... I'm not sure which is higher geared and by how much so I know what pinion I might want to use to be close to what I have now. I suck at this stuff. If anyone could help, I'd appreciate it. I changed my pinion from a 21T to a 20T just to be safe since I had one on hand. I was intending on changing it anyway since the ESC does run a bit warm as I had the 21T in there when I had tires smaller than the trenchers and never changed the pinion back. In doing so, I'm not sure I can make the pinion any smaller to deal with the new gear ratio if I have to. If I do, I may not be able to tighten the outside screws on the motor plate as the TVP will be in the way. Suppose I could dremel grooves in it...
Here are the RC4ME gears with tooth counts for anyone wondering:
The center diff was missing a shim in the gear side of the diff. The thing uses a weird bearing combination on the cup side. It has one bearing on the cup like a normal diff and another bearing on the shaft itself that goes on from outside the trans case vs inside. The front dog bone cup keeps it in place. The bearing on the gear side of the cup towards the rear of the truck was metal shielded. I replaced it with a rubber shielded one.
The diff cup "cap" in case anyone wanted to see it:
The inside of the diff was nearly dry with only a little bit of grease. Probably makes sense since most people would clean it out and put silicone oil in it anyway.
It didn't have locktite on any of the screws either. One of the output shafts is longer than the other. I didn't realize that until I had already take it apart and cleaned off the grease. I think the longer one goes on the front cup side... now I can't recall.
I used associated 500k in the diff before dropping the spider gears in. I put enough in so that it was nearly to the top of the x bars once they were installed and seated. I put a blob of 200k on top as I wasn't sure which way to go, so figured once the oil mixes, I'll be less than 500 and more than 200. lol
The final issue was when I installed the rear output shaft cup, the plastic grub screw retainer and a hair of the cup rubs slightly on the trans case. I dremeled a bevel in the retainer for a bit more clearance. It's barely rubbing. Guessing after a few minutes of driving, it will remove a bit of material and not rub anymore.
Will post up how it does hopefully tomorrow. It's supposed to be mid-90's here with high humidity... not sure I want to go outside, but I really want to see how this thing does.
The first issue, the input shaft isn't keyed to the hex washer like the stock input shaft. So, if the slipper slips, an unkey'd washer is going to be likely to spin with the spur and not the shaft which will be prone to cause the slipper to adjust itself on the fly if/when it slips. I used the original flux shaft in it's place.
The second, the gear ratio is different. I'm not smart enough to figure out which way it's different, just that it's different.
The stock flux hp trans I have has the following:
2 gear input, 18/23. The smaller of the two being used. 18 -> 44, the 44 is on the same shaft as the next gear, 33 which spins the output 29.
RC4Me trans:
1 gear input, 21. Spins gear 41 which is on the same shaft as the next gear, 31, which spins the output gear/diff 30.
I'm not sure if this math is right:
stock
18-44 32-29
18/44=.409
32/29=1.103
.409*1.103= .45
rc4me
21-41 31-30
21/41=.512
31/30=1.033
.512*1.033= .53
If that's the case... I'm not sure which is higher geared and by how much so I know what pinion I might want to use to be close to what I have now. I suck at this stuff. If anyone could help, I'd appreciate it. I changed my pinion from a 21T to a 20T just to be safe since I had one on hand. I was intending on changing it anyway since the ESC does run a bit warm as I had the 21T in there when I had tires smaller than the trenchers and never changed the pinion back. In doing so, I'm not sure I can make the pinion any smaller to deal with the new gear ratio if I have to. If I do, I may not be able to tighten the outside screws on the motor plate as the TVP will be in the way. Suppose I could dremel grooves in it...
Here are the RC4ME gears with tooth counts for anyone wondering:
The center diff was missing a shim in the gear side of the diff. The thing uses a weird bearing combination on the cup side. It has one bearing on the cup like a normal diff and another bearing on the shaft itself that goes on from outside the trans case vs inside. The front dog bone cup keeps it in place. The bearing on the gear side of the cup towards the rear of the truck was metal shielded. I replaced it with a rubber shielded one.
The diff cup "cap" in case anyone wanted to see it:
The inside of the diff was nearly dry with only a little bit of grease. Probably makes sense since most people would clean it out and put silicone oil in it anyway.
It didn't have locktite on any of the screws either. One of the output shafts is longer than the other. I didn't realize that until I had already take it apart and cleaned off the grease. I think the longer one goes on the front cup side... now I can't recall.
I used associated 500k in the diff before dropping the spider gears in. I put enough in so that it was nearly to the top of the x bars once they were installed and seated. I put a blob of 200k on top as I wasn't sure which way to go, so figured once the oil mixes, I'll be less than 500 and more than 200. lol
The final issue was when I installed the rear output shaft cup, the plastic grub screw retainer and a hair of the cup rubs slightly on the trans case. I dremeled a bevel in the retainer for a bit more clearance. It's barely rubbing. Guessing after a few minutes of driving, it will remove a bit of material and not rub anymore.
Will post up how it does hopefully tomorrow. It's supposed to be mid-90's here with high humidity... not sure I want to go outside, but I really want to see how this thing does.