Possible Transmission Problem ?

[PrivatePrevia]

What a day :doh: However I have to say , the Previas I have owned have always at least gotten me home . Today at not over 40 mph but hey , I made it :clap: . I'm pretty sure it's transmission related , lost power up hills , bad grinding noise . Don't think it's anything engine related ,not overheating ,and when it's in neutral it revs up and runs smooth. I can do a lot and I am a pretty decent DIY mechanic but I may end up turning this one over to power greater than myself , a paid mechanic .My ego may be a bit bruised over it but I have been having a few health issues ,mainly gout , and until I get back to 95% or better it's just what I need to do . Of course I am open to suggestions and things to check .

[timsrv]

I'm assuming it's an automatic.......right? Here's a couple threads where this is discussed on the "old school" Vanwagon automatic transmission:

http://www.toyotavantech.com/forum/showthread.php?1253-My-transmission-totally-crapped-out-help!!!!

http://www.toyotavantech.com/forum/showthread.php?742-newbie-needs-advice-re-brakes-and-transmission

The major difference in Previa transmissions is they are electronic shift (controlled by the ECU). The ECU uses information provided by a speed sensor and the TPS (Throttle Position Sensor) to determine what gear it should be in, then it will select the appropriate gear. If the transmission is slipping, this is bad & things will deteriorate quickly. If however it's simply not shifting into the appropriate gear, it could be an electronic issue (usually cheaper and easier to fix). Transmission work is usually expensive, so I hope it's electronic. Good luck. Tim

[PrivatePrevia]

Thanks Tim,
The only other thing I can think of is maybe the rear end is going:cnfsd:
Taking it to the shop tomorrow

[timsrv]

Let us know what you find out. I'll keep my fingers crossed for you. Tim

[TheMAN]

he has an S/C... they came with autos only... they have a fairly strong autos that is borrowed off the 4runner IIRC
it's likely that the rear end went... seems to be a common problem now that these vans are old.... toyota only speced them with 7.5" ring gears when they should've put in 8" like the hilux trucks and hiace vans... I had to rebuild mine and I upgraded to an Altezza LSD at the same time... expensive but worth it

[PrivatePrevia]

I had replaced the head gasket and the o ring on the distributor a few months back . After crawling under it and thinking it was the transmission or rear end I noticed the distributor cap was melted on the side. I checked the spark plugs, wires and replaced the cap. The distributor had oil in it so I pulled it out and put a fresh O ring on. To my dismay it still ran rough ,sounded like something was clanking or rattling , and has very little power when I drove it up the street. It only has 170k and I have had 4 of these and never had an engine problem. I guess it's time to go deep or take it to the shop and get busy on my day job. If you have any ideas or thoughts I would really appreciate it.
On a side note it still may be something simple . I used to work on things all the time and have recently over the last 18 months gone into another line of work . If you don't work on things daily you get a bit dull . :doh:
Will be going back in over the weekend if I don't have it towed to the shop . Swallowing pride and ego :rol:

[Burntboot]

I don't really speak Previa but it's been my experience that when the O-ring on a distributor fails, it leaks between the distributor housing and the hole in mounts in. Anytime I have run into oil INSIDE the cap, there has been an internal problem with the distributor and the only fix has been replacing the distributor.
Generally speaking there are bushings inside the distributor that are non-replaceble, when they wear they allow the shaft to wobble affecting the air gap for the rotor and consequently quality of spark among a pile of other things.
I would drop by the local yard and see if you can score a clean replacement and try swapping the assembly.
At least that would eliminate one thing from the list of possibilities.
BB

[Makelo]

X2 - Previas need to have the whole distributor replaced, not just the O ring. I did mine 40k miles ago and no oil burning smell anymore :)

[timsrv]

Since this is a continuation of your last thread I merged into one. Due to the sideways distributor on the Previa they are more prone to oil infiltration. Sometimes you do only need an o-ring. You should however always check the bushing for play before replacing it. If there is slop (shaft moves side to side), then a new o-ring won't solve anything. Based on your description I would also suspect a bad distributor. How did the rotor & inside of the old cap look? If it appeared as though there was any contact between these parts I wouldn't hesitate to replace the distributor. These Previas are very common now at the salvage yards and a good used distributor for a reasonable price should be easy to find.

Aside from the distributor, this could be caused by other things. I would try that 1st though and report back. Might not be a bad idea to do a compression test too. Tim

[PrivatePrevia]

I appreciate all the input . Tomorrow I may be able to go by pull a part and see if I can
snag an extra distributor.I did pull it and see if there was any play in it but found none . Still
want to believe it's something electrical. I have never seen a distributor cap melt like the
other one . Will post a photo of it later.:violn:

[PrivatePrevia]

Oh well, I tried a good distributor and it's the same . Even looks like it's smoking a little . The more I scratch my head the more I think HEAD GASKET .....I don't have a way to test compression so I am taking it to the mechanic tomorrow.If it is that I would rather just replace the engine and start fresh.Thoughts are welcome.:?:

[timsrv]

Check codes just to see if anything is stored. After checking codes pull the EFI fuse from the + battery cable fuse box and crank the engine. By listening to the way it cranks you can tell if there's a compression problem. If the compression is good the rhythm will be uniform. If the pulse of cranking is uneven there's likely a compression problem.

PS: Be sure to check codes prior to pulling the EFI fuse. Once that fuse is pulled, codes are cleared and you will lose the clues they can provide.

[PrivatePrevia]

I hate to tell this on myself but I had a bad catalytic converter :brainfart:
I have no idea why I did not think of this but it came to me when
I was telling a friend stories of my jaded youth and putting a potato
in a tailpipe as a prank. Well what goes around....... I cut out the
cat and it runs great . I may have to just knock the guts out and
run it like that for a while until I can get a new exhaust system shipped
to me .
I will say this , if you don't work on something every day you get dull.
Glad I found the problem and it was not the engine but I sure did take
the loooooong way around to find it . It would explain the distributor cap
as well with the muffler getting too hot and melting it . :rolleyes:

[timsrv]

Okay, I considered that for a brief moment, but the initial description of the problem threw me in a different direction. Glad you found it. Also check your EGR valve and modulator as these parts are also subject to heat damage when a cat plugs up. Tim

Lol on the potato karma! :roflmao:

[PrivatePrevia]

Tim , just a quick question . I have had a weird grinding noise at times /intermittent . It may do it
every 15-16 stops .Seems to go away at 30 mph .It idles fine and the lady I bought it from had just
had the SAD rebuilt when I got it .Any thoughts ???

[timsrv]

Rebuilt SADS doesn't instill a lot of confidence. SADS related noises will typically change or stop when in gear vs neutral (neutral usually makes noises stop). They will also change or stop when accessories are pulling loads (like AC running or alternator pulling a heavy load). You might try experimenting a bit by shifting into neutral or turning on AC when the noise occurs to see what affects it. Not really sure what else to tell you as noises are very hard to describe in writing :?:. Tim

[TheMAN]

idle speed also makes a huge difference in SADS stability and noises from up front... if your idle is low due to carboned up throttle/idle valve, this will cause intermittent issues

[tbkilb01]

idle speed also makes a huge difference in SADS stability and noises from up front... if your idle is low due to carboned up throttle/idle valve, this will cause intermittent issues
What about a chirping sound at idle (in drive) foot on brake? Turn lights on chip, brake.. Chirp, wipers...chirp...
I'm thinking alternator? SADS? Maybe a few degrees off timing?

[TheMAN]

probably loose belts or bad accessory mounts

[zak99b5]

What about a chirping sound at idle (in drive) foot on brake? Turn lights on chip, brake.. Chirp, wipers...chirp...
I'm thinking alternator? SADS? Maybe a few degrees off timing?


probably ... bad accessory mounts

I'm about to test fully this issue and solution. I should get the third mount tomorrow and install it Saturday.

[zak99b5]

Well, all new mounts, and I still get the squeak and chatter.

So I bought new SADS bushings.

What at else could it be?

[Kurtanius21]

Well, all new mounts, and I still get the squeak and chatter.

So I bought new SADS bushings.

What at else could it be?

Maybe try video taping the noise and posting it here via youtube. That would help us help you tremondously. I am still leaning torwards accessory belts.

[zak99b5]

I'll try to do that.

The belts seem to be excessively tight (i think in a previous attempt to quiet the noise?). Alt is at max extension.

I tried to to relax the tension a little yesterday from up top, but the bottom pivot bolt was too tight to move the alt in a little.

Ill do do a before and after video.

[timsrv]

Whenever belt noise is suspected, it can quickly be confirmed or ruled out with a can of silicone spray or belt dressing. While it's running, carefully spray the business side of the belts one at a time. If the noise changes or goes away, then it's a belt. If it stays the same, then it's not. Tim

[TheMAN]

wrong belts can also cause you to adjust the tensioner bolts to the max and it still won't be tight enough