Official Crawlbox BS thread!

yes, 23 spline in and out with marlin comp gears and the R151F sitting there still collecting dust

 

I’m ready when you are...

 

I have a question that perhaps someone on here can answer. I have a 2002 Tacoma, 3.4, auto, dual cases. (D60 / 14B, exo, etc) I bought the truck mostly built but have improved it here and there. The driveline is all as I bought it.

The front case is an Inchworm 2.28. The rear case is the stock Toyota case also 2.28. It has a clockable adapter (Inchworm I assume) so the rear case is clocked up. The adapter has its own fill and drain ports and from what I understand does not share fluids with the front or rear case. This makes sense based on the fluid level in the adapter versus the fluid level in the rear case. The front case has a drain plug in the "adapter" that is bolted to the back of it. (I believe Inchworm refers to this as the front adapter.) But I cannot figure out where to put the gear oil IN. I found some instructions for Inchworm crawl boxes for older Tacoma's and they clearly have a fill plug on the passenger side of the 'adapter' on the rear of the crawl box. But mine has no such plug.

Does anyone know the procedure to drain and fill this Inchworm crawl box? I attached pics of my set up if they help at all.

 

The fill is through the shifter that's the best way, but otherwise there should be a fill plug on the side of the adapter depending on what year and serial # yours is. Some of the older models did not have a side fill plug. I'd say undo the drain plug and measure how much comes out. The crawler/adapter should take around 3 qts of gear oil.

The front crawl box/adapter share fluid and the rear transfer case is separate from them and has it's normal transfer case fill/drain plugs.

 

Thank you!

So just to be clear...…

I attached a picture with numbers and letters.

So are you saying that the crawl box "A", adapter "B" and adapter "C" all share the same fluid? If that is so, then I should be able to open drain "1" and drain A, B and C. Then I should be able to refill A, B and C through port "3". This would put the fluid level in the crawl box all the up to the port "3" level which seems high, but makes sense if the capacity is around 3 quarts. However, in the pictures of Inchworm crawl boxes with a fill port for the crawl box it is located about at the level of my letter "B" in the picture (but on the passenger side), which is considerably lower than port "3". Which is confusing...…….

 

yes, but those you have marked aren't fill plugs. They look more of a level system if you installed a tube to keep an eye on the level. The oil should be about halfway between the top and bottom of the case. Again, some of these older adapters didn't come with a fill plug installed, don't over think it. Just remove the top shifter and fill with 3 qts and drive around and enjoy.

 

Yeah, I have been known to over think things, but I prefer simple over more difficult. If I have to go into thru the top, I have to pull the console out, pull the shifter boots off, thoroughly clean the top off, remove the bolts holding the shifter plate in just to add oil? seems like a PITA to me, but if that is what is needed, then I guess that is what I will do.

Thanks again for your help.

PS whether those are plugs for a site tube or fill plugs, shouldn't really matter. If I can get oil into them, then its in. The top plug has oil right up to it, as would be expected if it is indeed a fill plug for the adapter (assuming the adapter does not share oil with the crawl box, which is what I have read somewhere, that it does not share oil with the front or rear case)

 

FWIW I used to only put 1qt in my crawl box when I was running it in front of my chain drive case. Now with the lefty and crawl box sharing fluid it gets 2, anything over that and it pukes fluid out.

The easiest way to fill them is through the shifter hole like others have said.

 

I agree with u there. I can't see how the adapter wouldn't share the oil with the front box though. Every one I've seen they are shared whether it's inchworm, marlin, or trailgear. Now that only one guy is making the crawlers and merlin is always out of stock, I guess we can call them lowminchlin offroad, unless you go with a trail fail unit.

If you think it's easier to pump fluid through that tiny hole under the truck than to fill it from the shifter hole, i might have to question your sanity. It may take a little more time removing the console but just dumping the quart in through the shifter hole is 100x easier IMO. If you don't think that the low range box and adapter are shared, you could always experiment by removing the top "fill plug" you have and then refill and see when oil comes out of the fill check.

 

I take my shifters off and fill through the console every 30k miles. Removed fill plug and have a buddy check when it starts to dribble out I know I've filled enough


You can see both fill and drain plug here for the merlin

 

The rear adapter gets oil slung out the rear of the box through the bearing. The rear of the trans has a cavity that holds oil if you over fill it. So nothing's really shared so to speak. The only crawl boxes that share oil are the crawl boxes for the gear drive transfer cases.

As for the shifter, just pop the snap ring off the shifter base and pull the shifter out and fill through there, no need to unbolt the shifter housing on top of the box.

 

Ah, that makes more sense. I was expecting to have to remove the damn shifter plate, which would be a huge PITA. But if all I have to do is literally pull the shifter out, after removing the snap ring, well yeah, I can see that being far easier. The shifter plate is sealed with RTV so getting that back on would be a big deal. Thanks!!!

 

trust me, I question my sanity all the time! Especially when working on a rig I didn't build. Its just so much easier when you put it together you know how it comes apart.

And I do plan to experiment with the adapter. I will drain the crawl box first, and see if the oil level in the adapter drops. I am betting it won't. I will post up what I find. Least I can do...………...

 

Just get some 1/4 NPT male to barbed and some clear 5/16th hose. Pull plugs #2 and # 3. Put the barbed fittings in and attached the clear hose with small worm clamps. Then just fill till the levels in the middle of the clear tubing. Now you have a sight window. I should state for the record here I"m only guessing that's what 2 and 3 are for but it makes sense.

 

Sounds good, so is there a separate drain for the crawler box then? How will you drain it? Maybe I missed something

 

Morning all,

Got my install wrapped up with the exception of GL4 gear oil. Should be here tomorrow!

Quick question on the Trail Gear speedometer extension. I ordered it and installed it, but it seems like there is a piece missing on the tcase end. The nut gets tight but the cable still flops around - seems like there is a missing rubber piece in there.

Anyone used this that can comment?

 

Well I think I have run into another difference between the "older" version and the "newer" versions. There is no snap ring (that I can see) where my shifter goes into the crawl box. On top of the crawl box is the shifter plate, which has a raised section. Coming out of the side of that raised section (doghouse) is a horizontal shaft. That shaft has an "L" bracket welded to it. On the top side of the "L" my shifter rod is welded to it. Then across from that "L" bracket, there is an "assembly" that holds the shift linkage for the back case, hi to lo and 2wd to 4wd. So there is a lot going on on the top of that shifter plate.

I wish it were as simple as pulling a shifter shaft out and dumping oil in, but it sure doesn't appear that way. Unless someone can provide another way, I think that plate has to come off.

 

yes, there is a drain plug in the "adapter" at the rear of the crawl box. But there ain't no damn fill port, which to me is really, really stupid!!!

 

Ahhhh looks like you have an aftermarket sealed shifter. Looks like you are filling it from the bottom then, or unbolting that sealed shifter plate and dumping it in through there and resealing it.

 

Filling it from the bottom...………..can you elaborate? I wish I could fill it from the bottom! the only thing I can think of it to shove a tube up the drain plug, seal as best I can around it with a rag, pump 2 quarts of oil into the box and then try to very quickly get the drain plug back in before both quarts come back out. Probably lose at least 1 quart, and probably all but 2 trying that!