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View Full Version : Notes on manual transmission and TV 4x4 High low transfer transplant into 94 Previa



mountainhick
10-16-2013, 11:06 AM
It's almost done! In addition to the suspension lift pretty much like Tim did it, my 94 is now a 5 speed with 4x4 high low!!!

What a project. Took a lot of brain work to figure out all the adaptations and mods necessary to get it working well. For anyone considering this, here are my notes. I will add some pics of some of this stuff i took along the way.

In addition to swapping the transmission, transfer, clutch and flywheel themselves:


-Locate, cut out body and install the 5 speed shifter (pics post #2 below)

-Locate and install the transfer case shifter. (pics of transfer case shift mods in post #3 below) I used the floor shifter from the TV van the tranfer case came from. Had to cut off parts of old transfer case shifter bracket, modded it and had a plate welded to it so I was able to mount it in a good location, then had to create reinforcing plates for underneath the body's sheet metal where the bracket is attached. Also had to hammer a dent in the body to allow for the cup where the shift lever ball sits in the mount.

-Transfer case shifter cable was a PITA: cable from TV had to be shortened, and routing the distal end to the transfer case shift linkage took a major mod to the transmission mount hanger bracket. Difficult. To shorten, I cut the cable, drilled out the cable sheath from the housing that it was crimped into, and drove a pin into the crimp to re-expand it so it could be crimped again onto the trimmed sheath. The first test drive this connection failed, and I had to re crimp. I ended up using a coax cable hex crimper tightened in a vise.


The rod/eye cable end that attaches to the shift lever I cut off and had a piece of 1/4" brake line welded back on to become the crimp tube for reattaching the shortened cable. This was crimped with a wire crimp connector plier. Then drilled the housing barrel where this inserts since the fit was just slightly too tight.


The whole cable assembly had to be cut to correct length and final crimped into place in the installed location to ensure proper shift level adjustment/freeplay of 1mm. I measured and tested about ten times before cutting and crimping. A bit tricky, but worked out great.


-On the distal end of the cable, the transmission mount hanger bracket was directly in the way for cable to access the shift linkage arm on the T case. My solution was to modify the bracket by welding on reinforcing plates so the bracket is still strong enough to hang the tranny, then cut holes so the cable can run through and add a bracket arm for the cable housing barrel to be secured. The only path through the bracket misaligned the cable end too high to attach to the linkage arm, so it also needed to be offset. I measured an eyeballed angles for all this and had it welded up. It all looked great before hanging the tranny and driving, but on the first test drive the trans settled on its rubber mounts a bit lower. This made the offset catch in the bracket I had to remove the cable/bracket assembly and tweak it, grinding down the distal cable offset and opened up the bracket hole. Now there is needed clearance, and shifts wonderfully.

-To make clearance for this modded bracket and cable, the clutch line to slave cylinder had to be bent/re-countoured.


-At the Clutch housing/slave cylinder location, There was a bracket welded to the underside of the floor/body that secures a section of flexible clutch hydraulic hose. I cut this bracket out of the donor van's floor and custom fit it in its new location, It also had to be modded/lengthened for the added clearance mentioned above. This was pulled into the floor with carriage bolts from above and sealed into the body with RTV to silence any rattles.


-Had to drop the gas tanks to remove and re-install the rear part of the clutch hydraulic line from slave cylinder to clutch accumulator.

-front clutch line from master cylinder to clutch accumulator was not removeable intact due to a tight passageway obstructed by engine air intake tube which I could not figure out how to remove. So I cut the line into two pieces to remove. It also took dismantling a bunch of stuff under the hood; battery mount platform, air cleaner canister, a section of the engine air intake pipe and line brackets on the chassis to relocate this line. Cutting this line, it needed repair coupling and double flares added for the coupling. I botched several flares with a crappy tool before I got my hands on a good one, so also had to add a repair section of brake line tubing to repair the repair. Note: Toyota uses 12mm (flare wrench size) fittings for the clutch line. The tubing size is 1/4" and my repair was done with 1/4" SAE brake flare fittings.

-Brake pedal pad on an auto is wider side to side than brake pedals for manual transmission. To replace the pedal/brake pedal arm, meant removing the entire brake pedal bracket assembly. Another PITA! The also meant disassembling almost everything in drivers side under the dash, loosening steering column etc.

-located, cut out firewall and installed clutch pedal and clutch master cylinder, had to modify/re-locate wiring connector locations and a couple black boxes under dash that interfered with clutch pedal location, (I think they were the wiper control and seatbelt warning boxes).


-brake master cylinder reservoir supplies clutch master cylinder with fluid, The one for the auto trans doesn’t have the port for this, so I swapped the master cylinder, but its line ports are different so used one hydraulic line from the donor and had to re-bend the other line to attach lines to master cylinder. tube connecting fluid supply line to clutch master cylinder broke during the work. I had to make another fitting (Posted this in another thread)


-Clutch bleeding was nightmarish until I bought a vacuum bleeder system. Did the trick.

-Needed new clutch pilot bearing. Otherwise clutch and throw our bearing were replaced about 10K miles ago, so in great shape.


-drained and capped ends of the lines going to the transmission cooler after they dripped/drained for days!


-Replaced several other parts while I had the trans out. Distributor O-ring which was leaking oil onto the exhaust, a rubber boot on the transmission lever/linkage, rubber transmission mount.


Speedometer driven gear that was in the TV transfer case didn't work. I ended up using the speedo driven gear from the auto trans, and voila...


Rewiring:


-Clutch pedal: safety start switch, and cruise control release switch
-Transmission harness: MT and AT have different connectors, used MT harness slightly modified but re-pinned to connector from AT harness removed from vehicle to connect to its mate still on the vehicle. had to rewire/re-pin for backup light, speedo and hooked up 4WD switch in transfer to AT oil temp light in instrument panel. Wires for other AT functions disabled.


Added aftermarket tach, mounted on cowling over


Added keyless remote entry

mountainhick
10-16-2013, 12:24 PM
-Locate, cut out body and install the 5 speed shifter

Three of the four nuts were in place welded under the body to receive the shifter, I had to remove some of the sound deadening adhered to sheet metal, locate nut locations with caliper, drill to access the nuts, use a template rubbed from the donor vehicle to mark the cut out:


1132 (http://www.mountainserver.net/previa/transplant-1.jpg)

1133

1134

1135

1136

mountainhick
10-16-2013, 01:19 PM
Transfer case shifter and cable

placement of shifter:

1139



Shifter details, note:
-braket welded to base plate for mounting
-extra tabs added for boot (I'll have to make the boot cover)
-how cable housing barrel enters engine compartment (this will be sealed with RTV)
-brake line tubing used as new rod for cable end, welded to eyelet crimped onto cable
-dent hammered in body under ball cup

1140



modified transmission mount hanger bracket, reinforced then extra bracket arm added for securing cable housing/barrel, and 3/8 rod welded to cable end with added offset

1141



same bracket in place mounted under vehicle with clutch line re-located, and modded clutch line bracket where flex hose mounts

1142
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timsrv
10-17-2013, 12:47 AM
Wow! Thanks for the detailed write-up. You do nice work. Great job! I can see you're no stranger to fabrication and lay-out work. I like projects like this but I think I need to retire before starting this one (too many other projects piled up, not enough time). Very refreshing to see it done by a pro. Your documentation will save the next guy tons of time. This is exactly the type of write ups we want to see here :thmbup:. Please keep them coming :yes:. Tim

mountainhick
10-17-2013, 02:54 PM
Thanks Tim. Seriously, I'm no pro, just have liked working with my hands (and head) since I was a kid. This is my first serious auto mechanic project since the 70s.

Indeed, I posted exactly because it is the kind of info I would have liked to have getting into this. The challenge of figuring things out offers some of the spice of life, but having more info up front would have really helped. Bottom line for this project, swapping the transmission and transfer themselves is the easy part. All the rest is the challenge.

I'll add a few more photos when I get the chance