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View Full Version : CV Joints (The Previa Chronicles...Pt#3)



psychedelicode
02-27-2014, 07:09 AM
Been driving for a week with a bad CV joint. I can't replace it untill next week but need to do something now about it. Is it ok to pull the front driveshaft and cv's then just drive around in RWD? I had a bad ujoint in my 87 4runner and drove it around for a month in FWD by removing the rear driveshaft with no problems. However there's that pesky Viscous coupling on the Previa that I do not want to damage.

timsrv
02-27-2014, 11:42 AM
I'm not sure just how acceptable it is to do, but I ran my All-Trac for a couple weeks without a front drive line. I even had to punch it hard a couple times and got a chirp out of the rear wheels (something you can never do with full time 4wd). There didn't appear to be any ill effects from me doing that.

I seem to remember somebody else here trying it and they reported a turbine like sound when they tried to take off, then a sudden & violent engagement of the rear wheels. If I'm recalling the story correctly, they said it only did that once, then seemed okay after that.........so if you do it, do so at your own risk. Tim

psychedelicode
02-27-2014, 04:58 PM
Ok, well I did it. Cut the drives side one out and the passenger just came out. I have to report you cannot drive a previa without the front cv's in place. The front wheels started flopping around like crazy on the hubs as soon as I hit 40mph and you can hear the hub bearings tearing themselves up.. Also, the previa post 95 with the viscous coupling drives terrible in rwd. No power delivery to the rear wheels. Like you said, a turbine like sound coming from the transfer case which I can assume is the VC slipping. Which means that the later previas are FWD until something slips out back and there is no full lock up of the rear, just a torque split which by my buttometer is only 25%. This is probably why the earlier ones are better in the snow.
I guess i'm going to be without my van till next Friday when parts arrive from Rockauto.
I am glad that it was indeed my CV failing as I was beginning to think that it was a bad VC.

psychedelicode
02-27-2014, 06:07 PM
Will an earlier Previa not TV transfer case bolt up to a 97? There is a 94 alltrac with only 120k in one of the local yards it is an auto. Im thinking of pulling the CV's from it as well as the transfer case because it does not have the VC. Not that my van isn't excellent in the snow but it could be better perhaps?

timsrv
02-27-2014, 07:40 PM
My Previa experience stops in 93 as that's the newest one I've owned. I've never had an SC either. I am however fairly confident physical bolting-up would not be an issue. I know the transmissions for the SC previas are different (heavier duty) and I believe the gear ratio is different too. (SC's use different differential gearing to compensate). As for the transfer case, I have no idea as to what internal differences there may be, but I would be very surprised it wouldn't bolt-up.

If I were swapping a transfer case on a Previa, I'd look around for an 87 - 89 transfer case from a manual transmission 4wd van. This way you can get rid of the viscous coupling and you'll gain another speed in 4wd (They're 2 speed cases, high & low). To avoid problems with jerky turns you could just shift it into 2wd until the need for 4wd came around (still no way to disengage the hubs though). Tim

Note: If you did this, you'd also need to get an input shaft from an automatic 87-89 TV transfer case and swap it with the input from the manual transfer case. Toyota uses different splines for auto's and manuals (not sure why).

psychedelicode
02-28-2014, 11:18 PM
Are the TV t-cases 2 speed? I know absolutely zero about TV's. NVM re read your post.


How would I shift that 2 speed? Didn't you attempt this? The threads I have read were unconclusive or I may have not understood the conclusion?

timsrv
03-01-2014, 02:12 AM
87 - 89 4wd TV vans with manual transmissions had 2 speed transfer cases. Same year range with auto transmissions had single speed transfer cases. These earlier generation t-cases are physically interchangeable with each other and with the Previa transfer cases. The only problem with putting a manual transfer case on an auto transmission is the input shaft splines (autos & manuals have different spline counts). A cool upgrade for 87 - 89 4wd automatic van owners is to find a t-case from a manual van & install it on their auto transmission. The only hiccup with this swap is the input spline issue. The good news is the input shafts on these TV transfer cases are interchangeable. Since they're removing a single speed transfer case with the correct splines, they can swap input shafts between the two cases & make this mod possible. The 2 speed case is shifted via a separate shifter and cable that is usually taken from the same donor vehicle as the t-case.

This mod can also be done to the automatic Previa except you probably won't be able to swap input shafts. I say "probably" because I'm not aware of anybody who has tried this & don't know if the Previa T-case input shaft is interchangeable with the van T-case shaft (due to the viscous coupling I'm guessing not). There are at least 3 All-Trac Previa owners I know of who have successfully installed a 2 speed transfer case on their manual transmission Previas (without mods). If you were to attempt this on an automatic I would recommend having each flavor of TV transfer case available before starting the project. This will insure you have enough parts (input shafts) to complete the swap. Tim

TheMAN
03-02-2014, 10:50 PM
it was a bad idea to remove the front axles from the van... like many FWD cars, the bearings requires preload from the axles tightened onto the hubs in order to function properly.... without such preload, the bearings will be damaged

timsrv
03-03-2014, 12:42 AM
it was a bad idea to remove the front axles from the van... like many FWD cars, the bearings requires preload from the axles tightened onto the hubs in order to function properly.... without such preload, the bearings will be damaged

Lol, I'm just glad it was his van used to prove this (and not mine) :wnk: :LOLabv:

psychedelicode
06-11-2014, 06:43 PM
Well its been finished for awhile now. I put in new CV's, Struts, Ball Joints, Bearings and one Knuckle that was wayyy too expensive. The front of the van is very happy now and my wallet isn't.

On with the pics:
http://i97.photobucket.com/albums/l223/thunderchikn/CAM00143_zps6b21eafd.jpg (http://s97.photobucket.com/user/thunderchikn/media/CAM00143_zps6b21eafd.jpg.html)
http://i97.photobucket.com/albums/l223/thunderchikn/CAM00144_zpsd937fbe7.jpg (http://s97.photobucket.com/user/thunderchikn/media/CAM00144_zpsd937fbe7.jpg.html)
http://i97.photobucket.com/albums/l223/thunderchikn/CAM00145_zps8481c888.jpg (http://s97.photobucket.com/user/thunderchikn/media/CAM00145_zps8481c888.jpg.html)
http://i97.photobucket.com/albums/l223/thunderchikn/CAM00239_zps4b4640c7.jpg (http://s97.photobucket.com/user/thunderchikn/media/CAM00239_zps4b4640c7.jpg.html)
http://i97.photobucket.com/albums/l223/thunderchikn/CAM00238_zpsfbec08b3.jpg (http://s97.photobucket.com/user/thunderchikn/media/CAM00238_zpsfbec08b3.jpg.html)
http://i97.photobucket.com/albums/l223/thunderchikn/CAM00259_zps764054e9.jpg (http://s97.photobucket.com/user/thunderchikn/media/CAM00259_zps764054e9.jpg.html)
http://i97.photobucket.com/albums/l223/thunderchikn/CAM00260_zpsa2f26ce1.jpg (http://s97.photobucket.com/user/thunderchikn/media/CAM00260_zpsa2f26ce1.jpg.html)

timsrv
06-11-2014, 11:55 PM
Nice. The Monroe struts on my All-Trac have been failing for some time now. I have a new set of Gabriels to put on it, but thinking about putting those on eBay and getting the KYB's. I've run KYB's on one of my other Previas and was very happy with them. I might keep the Gabriels & experiment by welding on them. I would like to extend them 2" on the bottom so I can run bigger tires. I'm guessing I'll ruin them, but it's worth a try (tricky to weld without letting the pressurized gas out). Tim

mountainhick
06-12-2014, 08:19 AM
Are the TV t-cases 2 speed? I know absolutely zero about TV's. NVM re read your post.


How would I shift that 2 speed? Didn't you attempt this? The threads I have read were unconclusive or I may have not understood the conclusion?


I did the TV hi lo swap. Not simple. http://www.toyotavantech.com/forum/showthread.php?1493-Notes-on-manual-transmission-and-TV-4x4-High-low-transfer-transplant-into-94-Previa

Compared to Previa AWD with viscous coupling, the TV hi lo transfer sucks in snow. I have sourced a rear LSD to compensate, getting ready to rebuild the rear diff.

TV and Previa transfers are indeed bolt on, but the potential glitch is matching transmission output splines to a different transfer case and shifting

And, on auto TV, it is a vacuum system for 2wd-4wd, and on manual hi/lo TV you need a manual shifter.

timsrv
06-12-2014, 11:19 AM
That's interesting about the Hi/Lo sucking in the snow. Any other negative issues with it? Could you elaborate a bit more?

mountainhick
06-12-2014, 12:51 PM
That's interesting about the Hi/Lo sucking in the snow. Any other negative issues with it? Could you elaborate a bit more?

My understanding is without viscous coupling there is no limited slip between front and rear. It is not AWD functionality with the TV TC. With AWD the previa is the best snow car I have ever had. With TV 4wd it comparitively sucks in snow. Don't know what to elaborate upon.

TheMAN
06-13-2014, 01:24 AM
you should've bought the KYB GR-2s (silver struts) instead of the Excel-Gs (black struts)... the Excel-Gs are crap even though KYB says they're the same as the GR-2s... my experience says otherwise

also, why did you tear the dashboard apart?

psychedelicode
06-15-2014, 11:59 PM
Thats interesting about the TV sucking in snow. Although I must say my 4runner with 31" bfg all terrains was worse on ice than the previa, but when roflroflroflrofl got deep it would keep plowing where the previa would get stuck.
Is your van an s/c? Ive been wanting a five speed for ages!


The MAN: I had to tear the dash apart to get to the strut tower bolts.

TheMAN
06-17-2014, 02:52 AM
you had to tear apart the dashboard to take out the strut? HAHAHAH NO! You didn't have to! :no:
if you had just removed the knee panel under the steering column and the braces, you had just enough room to take out the left strut... you didn't even need to take off the steering column trim pieces! The only thing you had to take out was the passenger side airbag for the right strut

you wasted all that time for nothing

psychedelicode
06-17-2014, 07:14 AM
Actually, I tried that way and my ratchet was too big. I ended up doing it with a swivel and crowfoot wrenches. Besides it only takes 5min to take the dash apart. It reminds me of a snap together model car.

originalkwyjibo
06-17-2014, 12:26 PM
FYI on the TV t-case swap. The auto to manual swap requires changing the t-case input due to different lengths not spline count. It is a pretty straight forward disassemble and reassemble per the manual. My van is lifted with coil spacers and torsion bars cranked and the front bumper trimmed by the trails. I have climbed hills that required an angled approach to clear the front bumper with ease. I love my dual range t-case:)

timsrv
06-17-2014, 01:18 PM
This is good to know. Obviously I have not personally done this swap, I assumed it was a spline count issue. Tim

psychedelicode
06-18-2014, 09:52 PM
as an addon to original whatevers post. he did this swap on a TV not a previa, it seems that on the s/c awd previa that the s/c ( and its gizmoze are in the way of any transfercase shifting, and clutch master cylinder. This prevents the 5speed swap into a previa). its not even splines or length,( they are a part of the problem though). but there is NO room for a cluch m/c if you have a s/c previa.

TheMAN
06-22-2014, 02:48 AM
Actually, I tried that way and my ratchet was too big. I ended up doing it with a swivel and crowfoot wrenches. Besides it only takes 5min to take the dash apart. It reminds me of a snap together model car.

with my cheapo craftsman 3/8" ratchet and socket, and a gearwrench, I've been able to do this a couple of times on my van without having to rip apart the dashboard... taking off the lower storage bin/ashtray assembly, then the radio/center bezel, and finally the meter hood takes much longer than 5 minutes