Toyota Van 2-speed Transfer Swap into AWD Previa

[batook]

Success! After a day at the yard today, this is what I was looking at:



Found that plywood in the back of a pickup; best "floor" to cover the dirt that I've ever found at the yard for sure. This van was in really nice shape...it's a real shame the owner gave up on it and sold it to the pick-a-part instead of a TV enthusiast. Here's a picture of some of the frame...there really wasn't any rust on it at all.



Overall the pull went pretty smooth, despite the fact that the idiots who work at the yard tried to put the van on wheels to raise it but failed to actually LIFT the van off the ground (all tires were still in the dirt)...this added complications for removing the rear driveshaft and didn't give me much room under there to work, but I managed. All the u-joints in both driveshafts were totally shot. They weren't sheared, but they were *sloppy* loose...would need new u-joints put in by a driveline shop to be useable I think. A couple observations:

1) It does not appear that the front driveshaft can be removed unless the front diff is removed, or the transmission mounting is dropped to provide enough room to slide the shaft out of the transfer case output shaft; the front diff flange seems to obstruct removal otherwise. Any trick to this, or did Toyota not quite think that one through?

2) The transmission mounting with 4 vertical bolts going directly up into the frame crossbeams is a MILLION times easier to work with than the Previa's horizontal "pinned" mounting with bolts/nuts, at least in the junkyard where they don't allow jacks to support the weight of the transmission to take the weight off the bolts in order to slide them out. On Previa transmissions I've removed at the yard, it's a real pain to do by yourself; I've had to try to push the transmission up with my foot and then try to push the bolts out with my hand after I get the rear of the transmission positioned in the exact right spot. I've always been able to get them out, but it takes a lot of effort and swearing, and a contortionist I am not.

I really like the design of these TVs; it's cool to see how it's all laid out and where Toyota decided to stick everything. This is the first time I've really explored the underside of the TV, and it was a fun experience to see the configuration of the predecessor to the van I know so well. My favorite is the brake fluid reservoir on the side of the dash to the left of the cluster.

Alright, now for the bad news: unfortunately, when I got the transmission removed (and not a moment before), I discovered this bummer:



That's the fill hole. It's totally pulverized. WTF happened to it!??

Here's a close-up:





I pulled the drain plug from the rear diff and tried to thread it...this is as far as I can get it in (only 1-2 threads at best, still a big gaping hole):



I was going to just remove the transfer and ditch this transmission, but I figured I'd see what kind of deal they'd give me on it in this state. The manager agreed to $50 (core rate) for the transmission, and I figured it was worth it for that price, because regular price is over $150 with the core charge and fees. I havn't figured out a good way to fix it yet. If I weld up the hole, drilling it out and re-tapping would surely result in tons of metal filings in the gears, which would not be good. I'm thinking JB Weld might be the answer, but how to keep it from sticking to the plug? I'm hoping your brilliant ingenuity will come up with a solution Tim. Worst case, I could swap the internals with a good housing from a failed transmission. I can also pull another transmission in the future and use this one as the core return and get my money back for it.

I left all 3 shift cables attached, the clutch slave cylinder and clutch line/hose (which are NLA for the Previas so I'm sure it's NLA for TVs too), the 2-speed shifter, the complete speedometer cable all the way from the cluster to the transmission (that is a LONG run!) and a throttle body boot. I didn't get charged for any of that though, just the $50 transmission core and the transfer case. I got out of there with everything for only $160 including tax and fees, so all in all, I think it was a very good haul, and I'm pleased. I think I'll go back and pull the flywheel and see about door handles, just didn't have time to grab anything else today.

Couple more questions for my return visit:

1) Someone had removed the throttle body but it was still in the van, looks like they grabbed the TPS off of it though. Can you please post a pic of the "dash pot" on the TB that is NLA? Thanks.

2) What are the specs for the vane air flow meter so I can check it with my DMM? If it's still within spec, I'd like to grab a spare one of those too.

Now sure when I'll have time to install my new 2-speed transfer, but I will post here with pics when I get it installed and working. Might be a summer project though, so it could be a few months before I get around to it, so stay tuned. Eric

[timsrv]

You did good for 1 day......especially considering conditions. That damaged fill plug looks fresh. I'm guessing they busted it off with the tip of a fork (while picking up the van with a fork-lift). As a spare transmission it's still worth the $50. If I ever busted one it would just be a gear or a syncro, so I could crack the case and rob whatever was needed. It could be welded/repaired, but as you indicated it would need to be disassembled 1st. If you were going to that much effort then swapping guts into a good case would be easier. I guess there's the band-aid stuff like JB weld, but I would never feel comfortable driving around with that.

Here's a couple pics of a dash-pot:





The air flow meter on these seldom fail, but these are getting old, so anything's possible. Here's a couple pages from the manual on how to test.

[batook]

That damaged fill plug looks fresh. I'm guessing they busted it off with the tip of a fork (while picking up the van with a fork-lift).

Aha! Yes, that's surely what happened. Between that and their failure to properly lift the van, I'm not a very big fan of those guys...

Thanks for posting those pics, I'll see if I can find the dash pot when I go back. I havn't had a vane air meter go bad on a Previa either, but the one from my white 91 LE did test out of spec when I was doing a thorough inspection/reconditioning during its JDM engine swap 2 years ago. I replaced it with a good one from the yard, but I'm not sure if it made any difference.

Back on topic, how would you go about fitting the transfer shift cable/shifter into the Previa? I was thinking I'm probably (definitely) going to have to drop the rear of the transmission down to get enough room to run the cable over the engine and get it up to the shifter area. I suppose if I can run it up underneath to where it will reach, then mark that area and cut/drill a small hole large enough to get the cable through, that should work. I grabbed the grommet that lines the hole in the sheetmetal where the shift cable enters the cabin, so I'll try to make a similar sized hole whereever I decide to enter the Previa's cabin and re-use that grommet. I'm not sure if I can drill and tap mounting holes in the sheetmetal or if I'll have to weld some nuts in for mounting. I guess I'll have to see where the shifter ends up because I may have to fabricate some kind of platform to elevate it too. Just trying to brainstorm a bit and get a vision for it.

Also, do you think I can switch over the speedometer sensor to work with the Previa's electrical wiring sender? They look to be about the same size, so hopefully it will just thread in there and work, but I've never taken one out, so I'm not sure what it looks like in there. On the Previa I believe it is just a little gear that is driven by the TC to get the speed reading, so I'm hoping the TV works the same way, and that the gear just has a different tooth count depending on the final drive ratio (which is the case between n/a and s/c Previas, but I havn't confirmed they are swappable). BTW, out of curiosity, what is the FDR of the TVs? Thanks, Eric.

[timsrv]

All good questions. This is unknown territory so all I could offer is guesses and hunches. Considering the other similarities, I'd hope the Previa speedo parts would slide right in??? As for the shifter, I'm thinking the cable length will be sufficient, but who knows. Another option to mounting it on a platform could be extending the length of "stick". This isn't going to be shifted much anyhow, so it shouldn't be a big deal to reach down a bit further during those rare occasions. Tim

[Disco]

Could any of you tell me if the g59 Previa 5 speed manual will fit in a 1985 cargo van w 5 speed g53? I blew my tranny and am trying to find another option.

[timsrv]

Probably not. I'd go measure for you if I had examples of both, but currently the only transmissions I have uninstalled are for vans (none for Previas). I have 5 or 6 loose van trannys but nothing for 2wd. Good luck with your search. In your wanted ad I posted links to a couple of used 2wd g53 units currently listed on eBay. I hope that helps. Tim

[aspenjerista]

Aha! Yes, that's surely what happened. Between that and their failure to properly lift the van, I'm not a very big fan of those guys...

Thanks for posting those pics, I'll see if I can find the dash pot when I go back. I havn't had a vane air meter go bad on a Previa either, but the one from my white 91 LE did test out of spec when I was doing a thorough inspection/reconditioning during its JDM engine swap 2 years ago. I replaced it with a good one from the yard, but I'm not sure if it made any difference.

Back on topic, how would you go about fitting the transfer shift cable/shifter into the Previa? I was thinking I'm probably (definitely) going to have to drop the rear of the transmission down to get enough room to run the cable over the engine and get it up to the shifter area. I suppose if I can run it up underneath to where it will reach, then mark that area and cut/drill a small hole large enough to get the cable through, that should work. I grabbed the grommet that lines the hole in the sheetmetal where the shift cable enters the cabin, so I'll try to make a similar sized hole whereever I decide to enter the Previa's cabin and re-use that grommet. I'm not sure if I can drill and tap mounting holes in the sheetmetal or if I'll have to weld some nuts in for mounting. I guess I'll have to see where the shifter ends up because I may have to fabricate some kind of platform to elevate it too. Just trying to brainstorm a bit and get a vision for it.

Also, do you think I can switch over the speedometer sensor to work with the Previa's electrical wiring sender? They look to be about the same size, so hopefully it will just thread in there and work, but I've never taken one out, so I'm not sure what it looks like in there. On the Previa I believe it is just a little gear that is driven by the TC to get the speed reading, so I'm hoping the TV works the same way, and that the gear just has a different tooth count depending on the final drive ratio (which is the case between n/a and s/c Previas, but I havn't confirmed they are swappable). BTW, out of curiosity, what is the FDR of the TVs? Thanks, Eric.

I'm looking into doing something of this nature myself, I was wondering the outcome?

[Shxtbox]

Always loved the previa. I saw this thread and some others years and years ago.
I finally stopped worrying about my
Friends making fun of me and bought one.
I flew out to Phoenix to pick up Aaron alltrac 5 speed. Drove it home with a locked up
Viscous in the t case. I found a dual range transfer case from a 1987 toyota van and swapped it in.
It's a direct bolt in, besides the cable and shifter. I ground the pin off the shift lever on the t case and
Drilled a hole in it. I bought an aftermarket rock buggy shifter and set that up. Easy peezy.

Thanks for putting this info out there all those years ago, there is very little of it on thes vans

Randall

[92Prev]

Thanks for this inspiration! I, too, am thinking of doing this swap for my lifted '92 manual all-trac. Where did you source your t-case? I'm struggling to find any parts Vans around Teton Valley, Idaho.