Adventures in 4Runner'ing

[DouglasVB]

From Marlin's site:
In our opinion, the Ultimate setup is when a dual transfercase is built with one set of stock gears (2.28:1), and one set of Marlin Crawler's 4.70:1 gear sets. This is known as the Dual Ultimate Crawler. In a 21-spline application, due to the excess torque generated by the 4.70:1 gears, we will only build a 21-spline Ultimate Crawler with the 4.70:1 gears in the back case. But in a 23-spline application, the factory 23-spline input is much stronger, and therefore, the 4.70:1 gears can be placed in either the front case or in the rear, the choice is yours. In any of the available applications, two sets of 4.70:1 can be used to achieve a low range crawl ratio of nearly 500:1! More than 9 times lower than stock! We call this a Dual Ultimate Overkill Crawler since such a low crawl ratio is merely for bragging rights.

The transmission, unless it's been modified, has a 21 spline output. It's the W56 transmission. There could be a 23 spline coupler between the two cases though. I don't think there's any way to tell without dropping the T-cases and counting splines.

 

[DouglasVB]

Make sure your hood is not pushing down on the radiator cap. My aftermarket radiator was too tall and doing the same thing.

Ah interesting! I'll check that tonight. The hood doesn't pop up when I release the latch in the cab. Could that be part of it?

There's pretty clear evidence that the truck was in some sort of a front end low speed collision at some point in its life (some broken sheet metal, apparently replaced radiator, minor dimpling in the hood) so I wouldn't be surprised if everything isn't quite lined up in the front.

 

[BDGIII]

I have some friends early in 2000 that would put f150 radiators in their minis. They all said their trucks got real hot when crawl gears used. I dont think it really takes much for an f150 rad they are just thicker. I'm not sure tho.

 

[DouglasVB]

I have some friends early in 2000 that would put f150 radiators in their minis. They all said their trucks got real hot when crawl gears used. I dont think it really takes much for an f150 rad they are just thicker. I'm not sure tho.

Clearly this means I should run without a hood. That's legal, right?

 

[DaveInDenver]

I have some friends early in 2000 that would put f150 radiators in their minis. They all said their trucks got real hot when crawl gears used. I dont think it really takes much for an f150 rad they are just thicker. I'm not sure tho.

I dunno, it sure looks like a Toyota OEM upper tank in his photo. With the leaking issue he's having I wonder if someone brazed on a different neck or something. The overflow tube is even in the right place.

 

[DouglasVB]

I guess I should do a pressure test on my coolant system to see if I have leaks.

 

[AxleIke]

The transmission, unless it's been modified, has a 21 spline output. It's the W56 transmission. There could be a 23 spline coupler between the two cases though. I don't think there's any way to tell without dropping the T-cases and counting splines.

You almost certainly have 21 spline in both. Yes, it is possible the trans was modified, but I doubt it. There is almost zero chance someone bought a 2.28 set with 23 spline shaft, and a 4.7 gear set, and installed it with the 4.7's in the middle. Possible, but I doubt it. If they did, you will not be able to swap the gears.

Having had some time to think about this:

I would not change the gears around. You have an 80 horse motor on 35's. If you don't throttle it hard when you are really geared low, you won't break anything in the drive train.

You should be able to pop out the shift fork without pulling the case apart. Then you can cut it down, and fix the issue you are having. You will need a magnet to fish the roll pin out (magnet on a stick, very thin), or you can try turning the case upside down and knock it out. I would wad some paper towels or shop towels under neath the shift fork, so it doesn't fall all the way down.

That way, you save a lot of time. Up to you of course.

 

[DouglasVB]

I'm pretty sure the engine has been modified to produce more... something. Horsepower? Torque? The truck gets up and moves on the freeway unlike my old gold truck. Not sure if this really matters in the context of crawling low and slow though since the whole point is to move very slowly over an obstacle most likely at idle.

Would I still need to drop the T-cases out to pop out the shift fork? There seems to be decent access through the floor to the top of the T-cases.

 

[ToyodaTocco]

I think this is what Issac is talking about but I could be wrong.

If my memory serves me, the guy that Alex got the truck from said he installed the twin sticks but that the rest of the truck had already been built. He may of just thrown the sticks on and didn't do the rest or did it wrong.


http://www.lcengineering.com/LCInstructions/Trail Gear/2054059.pdf

 

[DaveInDenver]

You won't be at idle much with the Ultimate crawler. ;-)

 

[DouglasVB]

I think this is what Issac is talking about but I could be wrong.

If my memory serves me, the guy that Alex got the truck from said he installed the twin sticks but that the rest of the truck had already been built. He may of just thrown the sticks on and didn't do the rest or did it wrong.


http://www.lcengineering.com/LCInstructions/Trail Gear/2054059.pdf

Yup those are the sticks. They sure could have installed the shift knobs on the shifters backwards. Although I am fairly convinced that I have 2.28:1 gears in the rear case. Until I get the shift rail problem fixed, I'll have a difficult time telling for sure without cracking open both T-cases what's inside.

Here is a video I took yesterday of the truck (in 2nd gear because I'm dumb) in the various low range modes that I can get it into: https://www.youtube.com/watch?v=GYZC6VS96e8

I found a little bit of paperwork from the PO before Townsend with a receipt for the ARB air locker installs. Haven't found anything about any of the other modifications on the truck.

 

[AxleIke]

I'm pretty sure the engine has been modified to produce more... something. Horsepower? Torque? The truck gets up and moves on the freeway unlike my old gold truck. Not sure if this really matters in the context of crawling low and slow though since the whole point is to move very slowly over an obstacle most likely at idle.

Would I still need to drop the T-cases out to pop out the shift fork? There seems to be decent access through the floor to the top of the T-cases.

Yes. You need to remove the shift rail out the front of the case.

You need to do exactly What the link Bill posted has. Except instead of popping out the interlock, you need to cut that rail down on the end by 1/2 inch or so (grinder and cut off wheel work well, its hardened steel so sawzalls and other blades tend to just dull and not cut).

The crawl box and the tcase shift rails are exactly in line, and because the tcase is designed so the shift rail can move in and out of the tcase (as they show in the link Bill posted), if you don't cut the shift rail down, they hit each other when you try to put the crawl box in low and the tcase in high. Make sense?

 

[DouglasVB]

Yeah that makes sense. Looks fairly straight forward. I still need to decide if I want to crack open the T-cases to move the 4.7 gears (assuming that's what's in the front) to the rear T-case.

 

[AxleIke]

Just watched your video. Hard to tell since you are in 2nd. But I'm not sure about the 4.7s in the middle.

Do you have any other co-workers with any type of toyota 4x4? Or meet a club member?

If you can meet up, have both of you put the truck in low range: so ONLY put your rear case in low. Both in first. Then drive next to each other at idle. If they are leaving you behind, you have 4.7's in the rear. If you are only slightly behind or ahead even, then you have 2.28's. Even with tire size differences, the 4.7's are WAAAAYYY slower than 2.28, so you will know immediately.

Or, if you can, put the rear case in low, put the truck in first, and instead of idle, rev it up. If you are barely moving along, and the engine is screaming, you have 4.7s in the rear.

If you want to come up to Broomfield, I can hop in and tell you for sure, but that is quite a drive.

 

[DouglasVB]

I don't know of anyone in Golden with a similar setup. This evening I'll do the one-person test as you describe and take some video. My recollection is that the engine doesn't scream when the rear T-case is engaged in low to make it move somewhat quickly. Could be that I have 2.28 all the way around? I do have a set of 4.7:1 gearing sitting in my garage that I could put in if that were the case.

Tonight I'll make another video and will share it. We'll see how that looks and then if it appears that it would be useful for me to come up to Broomfield, I will. I could do that Friday afternoon/early evening.

 

[AxleIke]

No, no, I think you have 4.7's somewhere. Its just harder to tell in 2nd gear. Probably you have as you describe. 2.28 in the back, and 4.7's in the middle. If you can push the accelerator and the truck feels like its speeding up pretty good, thats a pretty good sign that you have 2.28 in the back.

I don't have time on Friday evening, but could do it saturday. But its probably not needed.

If you try driving next to another truck, you don't need anyone with a similar set up. A stock truck is fine. Toyota 4x4's in the US all have roughly the same low range gearing, enough that you will be able to tell, even with 35's against a stock truck. if you have 4.7's in the rear, you will get left behind by a stock truck, side by side.

 

[ScaldedDog]

Douglas, if you want to come down to Littleton, we can use my 2.28/4.70 runner as a point of comparison. I'll be I the garage evenings this week and over the weekend.

Mark

 

[AxleIke]

Oh, and you may just have deep gears in the diffs, rather than engine mods. 5.29's? 4.88's is actually about the stock gearing ratio for 35's on that truck, so with 5.29's (if that is what you have) you are geared deeper, and have better "seat of the pants" acceleration. I ran my first gen with 4.88's and 35's and it was about the same as stock.

 

[DouglasVB]

Townsend was told it was 5.29:1 in the diffs when he bought it. The speedo reads about 5mph fast at GPS-reported 65MPH (so at real 60 MPH, the speedo reads 65 MPH). At real 50 MPH, the speedo reads 55 MPH. I do have 5.29:1 gears in my garage that could be dropped in

I'll see if there's someone with a Toyota pickup nearby who will "drag race me" in 1st low. And I'll also re-do the video.

 

[DaveInDenver]

You can do this analytically.

MPH = RPM x Tire Dia. x reduction / axle ratio x 336

Transfer in high:
1500 RPM, 1st gear (W56 is 3.95) is 0.2532, t-case is 1.0, 5.29 final and 35" tires is 7.5 MPH
2.28 (0.4386)Transfer would be 3.3 MPH
4.70 (0.2128) Transfer would be 1.6 MPH
2.28 * 4.7 (0.0933) Transfer would be 0.7 MPH

Obviously doing the low range will be easier in higher transmission gears. W56 3rd is 1.38 (0.7246), same tire and RPM.
2.28 Transfer is 9.4 MPH
4.7 Transfer is 4.6 MPH
2.28 * 4.7 Transfer is 2.0 MPH