Gear drive transfer case onto 3vz-e manual tranny
 

Anybody got personal experience with this mod???

I'm gonna put a single RF1A into my manual tranny 3vz-e 1995 4Runner using a Trail Gear adaptor.

Just wondering what driveshaft and t-case mount to cross-member mods may be required so that I can decide how much downtime to expect for the case installation. Thanks for input.

I've studied the same thing, but got a good deal on dual cases and decided to go that route instead. Here's what I figured out for a single case RF1A swap.
- The tcase will move back by about 3/4-1 inch (the thickness of the adaptor). That may make the rear drive shaft too long - in my case the rear drive shaft is already compressed almost all the way, so doesn't have much room to take up that extra inch. My front drive shaft is also compressed fully, so would likely stretch enough to not need lengthening.
- With the tcase moving back, I suspect the crossmember mount wouldn't line up any more, and would have to be modified. Budbuilt sells a couple of different crossmember mounts to handle a single RF1 case with V6 adaptor, or a dual case setup behind the same V6 adaptor. Their mounts are expensive at ~$300, but they do provide significantly better ground clearance under the tcase and better protection for the case than the stock setup. (I see you are already using their crossmembers).

Are you going with a 4.7 low-range in the RF1A? I considered doing that but felt the 4.7 would be too slow for a lot of my offroad driving, so decided to go with duals instead for more flexibility. I'll post up later this winter when I get around to making the swap. I'll be interested in your experiences as well.

Yes, That is the reason for changing out the T-case.

The 4.7 gears are in the mail. I already have a single 4.7 case in my first gen 4Runner, and I like it. 5th gear low range is about the same as 1st gear high range.

Although there would be a little more flexibility with dual cases, I don't think that I really need them for the conditions I operate in, although I did buy a dual case crossmember, just in case, and I'm using it in single case configuration in my '87.

I'll post up when I get anything done. I have to build up the 4.7 case first.

I did seriously consider going with a single 4.7 case, but I do a lot of driving on backroads where I'm going up and down steep hills, running 5-20 mph. That's perfect with a 2.5 ratio, but the 4.7 would mean 4000 rpm at 20mph, and high range (1:1) is often too fast on the steep hills. I'm excited to try the dual cases.

I measured the distance from the front mounting surface of the VF1A case back to the first mounting bolt, and that distance is almost exactly the same as the RF1A with the V6 adaptor bolted on the front. So, it looks like the VF1A crossmember might fit the RF1A with V6 adaptor and no mods.

Great news, thanks.

I am more optimistic that the swap can be done without major changes to other components. The trail gear rep I talked to was not very knowledgeable.

Well, here's my RF1A case, newly built by me with mostly new bearings and 4.7 gears. V6 adaptor bolted up and ready to go.

It should be in my '95 Runner by this time next week.

https://cimg1.ibsrv.net/gimg/www.yot...e9903c549a.jpg

Looks great. How much of a job was it to swap in the 4.7 gears? I've read the Trail Gear instructions, and seems like a lot of steps. Was it tricky at all?

I'm going to install my dual case this fall after wheeling season is over, and I'm debating whether to change to the 4.7 gears in the rear case while I've got everything out on the bench.

Keep us posted about the install.

Ron

This is the second 4.7 case I have built, so it went quicker than the first one. The actual disassembly, and re-assembly of the gearbox is a piece of cake using the Trail Gear instructions.

The grinding of case and parts to make the new gears fit is a bit tricky, but really not so bad as I feared when first starting.

I had some trepidation about grinding the case to clear the larger gear, so I'd grind a bit, try to fit it, and then grind some more and after it'd clear, I ground it a little bit more to be sure.

The Hi-low shift fork, and the shifting piece on the 2-4 shift rail must also be ground to clear the new gear, so some fit and try is needed to get it right without removing too much material.

As for the TrailGear V-6 adaptor, it's pretty straightforward except NOWHERE!! do their instructions say that both shift rails MUST be shortened to where they do not stand proud of the adaptor flange when they are in their most forward positions.

There is no proper clearance in the rear void of the V-6 tranny for the RF1-A shift rails, so if they are not shortened, the case will not shift when bolted up to the tranny.

I was fortunate to learn of this looking at this thread::
https://www.yotatech.com/forums/f116...estion-293062/

After further consultation with a TrailGear tech rep who thought I wanted to talk about clearancing for 4.7 gears, he said that the hooked end of the 2-4 shift rail did indeed have to be cut completely off in order for the t-case to shift properly when bolted up to the V-6 tranny.

I did go for the Marlin strong detent springs, and the t-case clicks very strongly and positively into its different positions.

I got the VF chain drive case out of my '95 today and I made some measurements based on distances between the TrailGear adaptor face and the faces of the driveshaft flanges on the RF case, versis the measurements of the VF case face and its driveshaft flanges.

The pertinent data is that the RF1A case with V6 adaptor throws the transfer rear drive flange just about 3/4 inch further towards the rear than the stock VF case does.

My rear driveshaft was already very compressed, so I'm having it shortened 1 inch for safety.

The RF1A case and V6 adaptor throws the front drive flange just 1/8 inch or slightly more forward, compressing the front shaft just a smidge more than stock.

Since I am running stock IFS, I'm confident that the front shaft can stand this additional small compression. More to come.

Well, it's in there, just waiting on the driveshaft shop.

Spliced the '95 style plug onto an early RF two wire FWD indicator, so I expect ADD will work same as always.

My '95 has cable type speedo, so good to go there. Will have to see how the speed calibration turns out.

You can see from the Budbuilt skid plate that the RF!A case doesn't drop so low as the VF case did.

I may mod it a bit to take advantage of the increased clearance.

Tranny mount fit up to the original VF mount holes perfectly. Used TrailGear bombproof mount.

The shifter base does sit back a bit farther, but no mods were necessary.


https://cimg9.ibsrv.net/gimg/www.yot...2e10001bca.jpg

Looks good. I like the looks of what I can see of that Bud-built mount. Would you consider posting a few more pictures of it from other angles (directly beneath, front, frame attachment, etc.)? I've been considering ordering one for my dual case install.

If you put the same speedometer gear back into the tailpiece, the speedo cal should be the same, I would think. I think you can swap the actual gear over from your old case, even if the screw-in housing is different.

I'll post up some pics of the BudBuilt crossmember soon as possible. It's just a single case job , but I'd expect the double to be the same , but longer in the rear.

I am running a BudBuilt double one on my '87 runner using just one case. Always prepared you know.....

I'll look into switching the gear if the speedo is off. Thanks for the tip!!

Got my driveshaft back and finished up today. Got to watch the machinist true it and balance it. No weights were needed when he was done. Smooth as glass.

40 miles home in 105' heat @ 70-75 MPH. I expected there might be some felt vibration thru the stiff new tranny mount, but none apparent.

The tachymeter on my chronograph shows the speedo to be accurate to a mile or two, as close as it was before.

No chance to field test lo range yet. Here's a few pics of the budBuilt crossmember and belly pan::::

https://cimg7.ibsrv.net/gimg/www.yot...6e53ecfbc0.jpg
https://cimg8.ibsrv.net/gimg/www.yot...057cf8548a.jpg
https://cimg1.ibsrv.net/gimg/www.yot...2a2f5b72ea.jpg
https://cimg4.ibsrv.net/gimg/www.yot...0fa41bc744.jpg

Got about 600 miles on it now and a couple good low range workouts. No leaks, or vibrations. I'm really likin it!

About time to drain the first gear oil.

I'm using first and second high range a bit more more than I used to on the better parts of trails where I used to use 4th and 5th gear low range; Because low range is now indeed LOW.

But, man, when it's steep, and the rocks are big, there's nothing like lockers and a 4.7 case.:nerd:

Are you still liking the new case? One thing I was wondering is if you noticed any difference in noise and/or ease of shifting in and out of 4wd with the RF1A case vs. the VF1A. The chain drive is supposed to be quieter than the gear drive, but I don't know if it's noticeable. Also, the VF1A has spring loading on the shifter so you can move it into 4wd and let go of the lever, and the actual tcase will shift whenever the drivetrain windup relaxes. I think The RF1A requires you to keep pressure on the lever until it actually shifts. Do you find that annoying at all?

I'm hoping to get started on my dual case swap in the next few weeks now that the snow is flying in the Colorado mountains and the trails are pretty much all closed.

Ron

Yes, I still like it. Lots of steep rocky terrain here that I like the very low gears for.

With the 4.7s; 5th gear low range is about like first gear high range.

It is now too low to use low range 2 wheel drive as often I used to for engine braking on many slightly steep descents, but first gear high range and just a little brake suffices.

You will have the best of both worlds with dual cases. I advise against a 4.7 in your rear double case. Save your money, you will never have use for it.

The 2.7 case compounded with another 2.7 will be plenty low.

As to shifting, I have never found any reason to shift any t- case into 4WD on the fly. I just don't do it.

I do occasionally shift from 4 wheel high into two wheel high on the fly as there can be no issue just disconnecting the front.

High range is just as quiet as ever, but low range growls some, not much different than the RF-1a did with stock gears, or the chain drive case did.

Start a thread when you start work on yours RJR, I'd like to see it!.

Thanks for the update and encouragement. I'm looking forward to getting going. I hope to start the prep work on the dual cases next week, get all the miscellaneous parts ordered, and then get to the actual installation probably after Christmas. My son-in-law who loves 4runners and wrenching on them will be here for a week between Christmas and New Year. Maybe we can spend some "garage bonding" time and do the install then. It'd be great to have some help.

I'll try to post pictures as it goes along.