Probably a grenaded transfer case

[DouglasVB]

Talked to a gentleman at Advance Adapter. He's heard of this problem before. The issue is the Marlin Crawler 4.7:1 full length splines are too short versus the Advance Adapter dual bearing coupler expected spline depth. And the old Advance Adapter single bearing coupler is a different length and thus incompatible.

So the guy at Advance Adapter said I can either grind material off of their coupler splines or off of the Marlin Crawler gear input shaft splines. Or get different 4.7:1 gears. Or switch back to 2.28:1 gears.

I'm thinking grinding is the answer and I think that probably the input shaft coupler would be cheaper to replace if I screw up. I could gingerly attack it with a Dremel tool. I need to gain somewhere between 1/8" and 1/4" of extra room.

Does that sound reasonable/logical/safe?

 

[J Kimmel]

Yep grind away try not to go deeper than the splines

 

[DouglasVB]

If I go the Dremel route, I'll see about getting some cut-off wheels for metal and just take my time slowly grinding material away.

I'm tempted to do it right where it is rather than removing it from the housing so that I can test-fit and also because it's a pretty good way to hold the input shaft steady. I would cover all the openings on the t-case with some blue painters tape to keep ground up bits of steel from getting in the case.

 

[DouglasVB]

I've been poking around online to see what other people have done in similar situations in the past with the rear t-case input shaft being not quite right for the adapter coupler.

Someone in the local-to-me 4x4 FB group had the same problem a few years ago and just took an angle grinder to his input shaft. He said the issue was not the spline length but instead the part directly behind the splines wasn't cut far enough back. He's been running four years with the ground down input shaft with no problems.

I found an older post on the Marlin Crawler forums from Big Mike that said to grind for a similar scenario: https://board.marlincrawler.com/index.php?topic=94577.0;message=1057274

Here's another similar post from the same time period on Yota Tech: https://www.yotatech.com/forums/f31/dual-t-case-install-276358/

And on the Advance Adapters transfer case page, they talk about input shaft grinding for older gear sets: https://www.advanceadapters.com/tech-vault/3-transfer-cases--adapters-toyota-trucks/

So I think that this indicates it's not too big of a deal and I shouldn't be too scared of the modifications that need to be made...

 

[DouglasVB]

Well the t-cases are back together and ready to go back into the truck.

I ended up using a Dremel with a grinding wheel to clearance the end of the input shaft spines enough to work with the new coupler. It's not the prettiest job but based on the old forum posts that all talked about using angle grinders to do the same thing, I think I ended up with an okay product. Or I just created a ticking time bomb. 🤷🏻‍♂️ But considering the donor t-case had most of its oil slinger in chunks in the bottom of the case and it was otherwise just fine, I don't think throwing off the balance a tiny bit is a big deal in this application. I may have created some stress concentrators though by taking the Dremel route rather than finding a machine shop that would do the work or making the long drive to a friend's house who has a metal lathe. Or maybe not.

I was surprised at how soft this steel is. It makes sense that there are plenty of pictures of these input shafts twisted around or snapped in half. Good thing I'm running the stock 22RE with small power

As long as the weather holds, I'll hoist this back into the truck this evening after work. Then the major piece of remaining work is to figure out a new e-brake setup since I've decided to ditch the driveline e-brake. I'm looking at using 1980 Supra rear calipers like what Roger Brown has been trying recently. I corresponded with him about those calipers and he said he just bought a "full loaded" set from Rock Auto so I'm thinking about doing that once I have verified that everything else is working well.

 

[rover67]

Nice! did the rest of the assembly go together OK? is it all nice and clean??

 

[DouglasVB]

Everything went flawlessly with reassembly after I did that grinding. Nice and smooth shifting on the bench.

I tell ya... I look at all this aftermarket stuff (the gears, the t-case adapter, etc...) and it makes me wonder if an engineer was actually involved in the design of this stuff. I can see the design intent in all of the Toyota OEM parts but I really wonder about the aftermarket components.

 

[DouglasVB]

Got the t-cases back up in the truck today. It's almost back together except the new rear drive shaft flange is drilled for 10mm bolts and the bolts I have are 11mm bolts. So I'll pick up some 10mm bolts tomorrow.

I also found out once I had the t-cases in the truck that the front output shaft flange doesn't match the front driveshaft flange. So I had to harvest the one off of the old rear t-case and put it onto the new one.

I still need to order up some 1980 Supra rear brakes to see if those will work to give me an e-brake at the rear axle. I ditched the driveline e-brake finally.

Tomorrow I'll grab the smaller bolts at one of the local parts shops and get the rear drive shaft attached. Slowly but surely...

 

[DouglasVB]

I ended up having to order drive shaft bolts. None of the local parts shops actually had them in stock even though their websites said they had them. Talked with the driveline company and they said to go ahead and drill out the bolt holes to whatever I need, and that their flanges are meant to be drilled as needed. So I've got the right size drill bits on order, too.

Now I'm puzzling over how to get an e-brake again. It looks like supra rear brakes are really rare anymore.

I really don't want to go back to a driveline e-brake.

The drotor kits from FROR look great but I don't want an extra 3.25" on my axle width at this point. I don't have any plans to upgrade my front axle and it already has spacers to match the rear axle width.

I see some people have used Cadillac El Dorado 1976-1977 rear calipers that you can get new: https://www.ruffstuffspecialties.com/R2262-A.html but I also see people complaining they're really challenging to get adjusted properly.

Then I see a lot of old forum posts across the various Toyota and 4x4 forums that talk about a wide array of different potential options (Montero disks with Mustang GT calipers, for instance) but don't provide enough info to know what parts to buy.

I could do a hydraulic line lock but I'm not sure that would pass the spirit of tech inspection at Cruise Moab and other 4x4 events.

 

[DaveInDenver]

TLCA's requirement is for the emergency/parking brake to stall the engine in 3rd gear. I don't think there's an explicit rule against a line lock but I believe various DOTDMVFHWAgov regulations require that the emergency brake is supposed to be mechanically independent of the hydraulic service brake system so some things are probably assumed.

 

[DouglasVB]

Going with the Droter kit does seem the best way to get a mechanically independent e-brake. Considering that when I had a failed axle half shaft spline in the past, I lost the ability of the driveline e-brake to do anything without the locker engaged (and of course I didn't think about the locker at the time), it's not like driveline e-brakes do much better than a hydraulic line lock anyway.

But that extra axle width... kinda seems like I should have both axles be the same width.

 

[DouglasVB]

I've been looking at combined brake caliper and e-brake options beyond the unobtanium supra calipers. There are a variety of calipers that have integrated mechanically actuated e-brakes. And there are a lot of very old forum postings with people complaining about them.

My truck isn't close at hand so I can't measure the caliper key dimensions and I've been having a heck of a lot of trouble trying to find it on the internet. At least the disk dimensions are available.

(from here)
Brake Rotor Diameter : 289 mm
Height : 64.5 mm
Vented / Solid : Vented
# of Bolt Holes : 6
Brake Rotor Discard Thickness : 18 mm
Brake Rotor Thickness New : 20 mm

The question is what the dimensions are on the Toyota minitruck calipers especially with the mount center distance and bolt size.

Some combined caliper e-brake situations I've found:

• https://www.speedwaymotors.com/shop/speedway-disc-brake-calipers~8207-10191-4434-3-548-14438
• https://leedbrakes.com/i-23439368-replacement-rear-caliper.html
• https://lugnut4x4.com/product/emergency-brake-kit/
• https://www.ruffstuffspecialties.com/R2262-A.html
• https://www.littleshopmfg.com/parking-brake-calipers-with-pads-and-pins-for-dbc-kits/

I suppose another approach would be to do the Drotor upgrade and also do the IFS front hub conversion. At least I *think* I don't already have that considering I've got wheel spacers. I do have 15" rims though. Below is an *old* photo of my front axle but it's still the same setup:

I thought I had more photos from the various times I've had to take apart the front axle but I'm not finding them. If I did do the IFS front hub conversion, it is my understanding I'd gain something like 3" of axle width before adding spacers. So if I kept the spacers and did the IFS front hub conversion, then it would match the rear axle with the Drotor kit.

-------------

EDIT:

I've found a lot of different vehicles that have the integrated mechanical e-brake calipers. For instance, a Datsun 280ZX. And a recent VW Beetle (~2009). Even a Ford Mustang Cobra. So they must no all be hot garbage.

The big problem I'm having is finding dimensions to compare against what's on the truck's rear axle now (I believe it's solid front axle calipers so 1985 and earlier).

So here are some links and notes for later reference:

• https://www.silverminemotors.com/da...kit-individual-parts/rear-stage-4-kit-caliper - appears to be Mustang Cobra brakes
• Nissan Maxima rear calipers
• 3rd and 4th gen Camaro rear calipers

 

[Hulk]

FYI: Line locks are OK for Cruise Moab. We changed this about 5 years ago.

 

[J Kimmel]

Between a line lock and third gear let the clutch out in low low you’re stalling instantly

 

[DouglasVB]

I'm still waiting for the four driveline bolts I need to finish up the truck and get it out of my friend's driveway. They might show up by next Tuesday.

In the meantime I've been continuing to contemplate e-brake options.

Would it be completely stupid to throw a second set of Toyota calipers on the front mounting points on the solid axle knuckles? I could use one of those hydraulic e-brake setups then to actuate those calipers. Or is there a reason that parking brakes are usually on the rear axle?

I was also thinking I could make some sort of adapter plate and have a set of mechanical calipers on the rear axle similar to what these guys appear to be doing: https://www.performancebrakesunlimited.com/bbr345xr.html

I could use something like these Wilwood mechanical calipers then: https://www.wilwood.com/Calipers/CaliperProd?itemno=120-15353-BK or I could go with the hydraulic e-brake setup. Mechanical would be easier from a cab modification standpoint because I really don't have the room for a floor-mounted e-brake handle.

I can't find these on the actual Wilwood website and they'd be the wrong size but they're interesting: https://www.motorsport-tools.com/wi...-caliper-handbrake-cable-attachment-22mm.html

Anyway... still thinking about what to do.

 

[DouglasVB]

Got the rear driveline on. I'm all set to drive the truck again. Still no e-brake solution but I'm mulling over options. The easiest probably would be to throw a second set of Toyota calipers on the front axle and use a hydraulic e-brake setup.

I could build a bracket that attaches to some of the bolts that connect the axle housing to the full floater adapter so I could hang some mechanical calipers.

I could attach another set of Toyota calipers on the front tabs on the front axle knuckles and use a hydraulic e-brake setup.

Still to-do: road test the truck. It's a PITA to get the truck out of the driveway that I have it in so I've been avoiding it.

 

[DouglasVB]

I'm also trying to find the dimensions on Isuzu Trooper rear calipers to see if maybe they'd be a direct swap. Anyone have an extra set kicking around?

 

[DouglasVB]

Of course I'm still thinking about what I'm going to do for a parking brake. Brian over at FROR is making some really good points about installing a taco brake kit on the front to widen the front axle and then install the Drotor on the rear to match (and get that parking brake). I'd have to grind off one of the sets of brake tabs on my knuckles (I have six shooter knuckles) or upgrade to FROR keyed steering knuckles.

So I'd install this on the front axle: https://frontrangeoffroadfab.com/full-tacoma-brake-mounting-kit/
And this on the rear axle: https://frontrangeoffroadfab.com/drotor-backing-plate-kit/

One question I have is if the taco brake mounting kit will work with the 15" rims that I have. The front axle already has v6 pickup brakes that fit just fine.

 

[DouglasVB]

Took the truck on its first drive today since the incident. The t-cases were great. No troubles with them. Everything shifts smoothly. 2wd, 4wd, hi, low, very low, low-very low. Reverse, a variety of forward gears, all good.

Unfortunately there is a vibration between ~45 and ~60 mph.

I put the rear t-case in neutral going downhill on the highway and still had the vibration so that rules out most of the t-cases, transmission, and engine.

The rear hubs and differential were warm when I got back from the test drive (about 30 minute test drive) but not hot. The front hubs and differential were cold.

Here are my thoughts on what could be wrong:

1. Tire under-inflation or out-of-round or thrown wheel weight (almost guaranteed that they're all out of round and under-inflated)
2. Bearing(s) going out in the rear axle hubs (last rebuilt about four years ago with all new bearings, last inspected maybe two years ago when re-packed the grease)
3. Rear differential problem: bearings, gears, something (last inspected and rebuilt about five years ago by Jackson)
4. rear driveshaft (that was just rebuilt and balanced) is not balanced (unlikely since it was just rebuilt and balanced -- this driveline shop has a very good reputation)
5. Bearing(s) associated with the rear output shaft on the t-cases going out (unlikely because I checked all of them and everything associated with that, and it all looked good)

So I'm going to take my inflation gear over to where the truck is parked tomorrow to inflate the tires and try another test drive.

Then after that I guess the next thing would be to take apart the rear axle and inspect everything.

 

[rover67]

what is the frequency of the vibration? does it match tire RPM or driveshaft RPM?