Over Drive issues

[Dan G]

First I want to thank you all for the priceless info. I have got from this forum. I've fixed everything from a/c issues to egr , O2 sensors and a few things in between!
now for the current problem....
When my 1996 Previa is in OD, it jerks like crazy if I try to accelerate at anything faster than a snails pace between 50-60 mph.Once I am cruzing at 65+ mph, it's fine ( unless I floor it going up a steep hill ect) then it jerks a bit
No problems in any other gear than OD. Any suggestions??

[Makelo]

Hmm, maybe your SADS is going out?


WIth the overdrive on mine, I think I might have an electrical problem because when I press the button to de-activate and have the van shiftdown to 3rd gear, it does not desengage. Even the light on the dash does not turn on

[pdgizwiz]

I had an issue with the OD on one of my vans that may or may not be of a similar nature:
When it shifted in or out of OD on the highway, there would be a shudder that felt exactly like I was going over a rumble strip. At first I thought that's what it was, but soon realized that there were no road features that corresponded with the noise, and figured out that it happened when the trans shifted.
I drained the transmission (about 3 of the 6 qts drained out) and replaced it with new fluid. The problem vanished.
Moral: Automatic transmission fluid loses its magic properties in time. If it hasn't been replaced recently, or - more likely - you don't know when it was changed, do so.
I also changed the filter and replaced the pan gasket, but there were no shavings or anything so I don't regard this as having been part of the fix. Just refreshing the fluid did the job.

I figure that I have 50% new fluid now. If drained and refilled it again, I'd be up to 75%. I sold that van, though....

[Dan G]

I had an issue with the OD on one of my vans that may or may not be of a similar nature:
When it shifted in or out of OD on the highway, there would be a shudder that felt exactly like I was going over a rumble strip. At first I thought that's what it was, but soon realized that there were no road features that corresponded with the noise, and figured out that it happened when the trans shifted.
I drained the transmission (about 3 of the 6 qts drained out) and replaced it with new fluid. The problem vanished.
Moral: Automatic transmission fluid loses its magic properties in time. If it hasn't been replaced recently, or - more likely - you don't know when it was changed, do so.
I also changed the filter and replaced the pan gasket, but there were no shavings or anything so I don't regard this as having been part of the fix. Just refreshing the fluid did the job.

I figure that I have 50% new fluid now. If drained and refilled it again, I'd be up to 75%. I sold that van, though....

I dropped the transmission pan and replaced the oil that was in it. I used castrol import oil that claims it meets Toyota specs. Do you think that may be part of the problem? I had no issues before the partial transmission oil change. Levels are where they should be on the dip stick...

[pdgizwiz]

I would expect any Dexron equivalent ATF to play nicely in your transmission. FWIW, I used Valvoline MaxLife, but any new ATF should be better than any old ATF.

I'm no oil expert, and even if I was I wouldn't admit to it in an online forum. Oil is a flammable subject.

[cvtroger]

Wonder if there is an electrical component that might need replacing. I am not sure, but I also would think a code would be thrown if it did.

A month back when my transmission started to fail horribly (my issue was the lower gear clutches going out and the front drum was burning).

I had a the shop that rebuild my motor test drive it, but then I had a transmission shop drive it shortly after. They both had the same conclusion.

While my transmission was being rebuilt, the OD planetary gear was changed as well because it was contaminated and damaged.


Anyways, doesn't hear to get a specialist to test drive it IMO.

[Dan G]

So I finally figured out what was causing the banging noise and jerking at around 50-60 mph. It is my S/C. I disconnected the S/C relay and problem has gone away. Aside from removing it, does anyone know how to change the electromagnetic clutch on a S/C?
she has less than 175000 miles on her and is in near mint shape, no rust and sunroof/ moonroof.
but if I can't fix fairly cheap, my wife will be ready to get a diff. Ride
Any ideas will be greatly appreciated!!!

[James]

So I finally figured out what was causing the banging noise and jerking at around 50-60 mph. It is my S/C. I disconnected the S/C relay and problem has gone away. Aside from removing it, does anyone know how to change the electromagnetic clutch on a S/C?
she has less than 175000 miles on her and is in near mint shape, no rust and sunroof/ moonroof.
but if I can't fix fairly cheap, my wife will be ready to get a diff. Ride
Any ideas will be greatly appreciated!!!

Hello Dan and Dan's wife. First of all, I think you would be making a huge mistake parting with your Previa. The Sunroof/Moonroof design only was available on the 2WD model. That rear sunroof clears heat in the van fast. As for fixing the Super Charger, I have a 1991 Previa LE 2WD with the Sunroof/Moonroof and I love it! The supercharge didn't come out until 1993. Mine kicks butt! Thanks to the kind people that share these websites with us, maintaining your Previa is easy! Parts are parts, just like an old antique airplane, keep putting parts on it it will run forever... Sun Roof Previa's are cool. James