Toyota Previa (1995) vibration on deceleration. Have already changed the front drive shaft couplings, but the vehicle still vibrates when slowing for a stop.

Yes indeed.

You want to get the vehicle drive shaft (torque tube) checked for any loose end play... paying particular attention to the "U-joint" area.

As bad as you are describing it it sounds like you are really close to dropping your drive shaft...

DO NOT work on this yourself if you are not TOTALLY familiar with good jacks... jack stands... wheel chocks and have a level work area available... also keep in mind that while your TRUCK may be in PARK... that is only as stable as your drive-shaft.

Don't get between your truck and a hard place until you get that DRIVE-SHAFT fixed...

Another hot tip... if you are going to the trouble of removing the drive shaft... replacing both "U-joints" would save money and time in the long run.

Be safe... work safe!

http://www.rangerforum.com/threads/u-joint-replacement.6756/

UN-Edited response via comment line:
Oh yes indeed.

It appears that the Ranger can come in many different configurations... but the rules of home trouble shooting are to go after the cheap and obvious probabilities FIRST, (loose lug nuts) then on to the rear-end... CV-joints (if you have them)... wheel bearings... finally back up into the transmission.

Seriously... look that drive-shaft over:

Have an assistant hold one wheel while you move your rear wheel... while you are watching the drive-line... the offending u-joint should reveal itself by showing some free-play.

These should be very tight...

Perhaps then when you look more closely you will see the HORRIBLE (chocolate) brown color of oxidized iron... ALWAYS an imminent sign of DANGER anywhere on your vehicle.

The u-joints can be pretty bad... and the vehicle still run... but once that drive-shaft drops your parts costs will escalate vigorously (assuming everybody survives (my drive-shaft didn't... but mine did NOT warn me (silent failure)).

Please do have a look at the URL I posted with my first reply.

Be safe!

check the front tie rods jack car up and see if front tire moves from side to side or feels loose

I replaced my drive shafts on my 96 Previa LE SC, so I know it can be done. If you don't know the difference between the auxiliary drive shaft and the front or rear drive shafts, then you probably want to have someone do it for you. The auxiliary drive shaft coupling replacement is a difficult job. It is covered in manuals available in auto parts stores. $20 for the manual is worth it if you decide to do it yourself.

You should check tires for uneven wear,wheel bolts. Also loose parts in suspension.

check front brake rotors sounds like there warped..or it might be in your drive shafts check for looseness

u mean is knocking noise?
i think it came from the shaft in front of engine that drives the accesories pully in front. when the a/c is running or the rpm rise up a bit, the noise is gone. try go under the vehicle and spot where the noise come from. as i know is come from the shaft in front of the engine. the coupling need to be replace.

check the drive shaft between the intermediate transmission and the front transmission for miss alignement and defectivness of the telescopics system of this shaft. we had about the same problem on our 1996 same model...

remove the rear drive shaft and redrive it. it could be the drive shaft or the angle gear (the front of the drive shaft bolts to the angle gear).

My 96 low rumble was caused by the U joints on the drive shaft. The front drive shaft starts near the rear of the vehicle, transfer case. The U joints are non-replaceable, so I had to buy a new one from Toyota. The parts guy said it was the only one they could find in the US. Around $650. Alternative was to ship the drive shaft to an outfit in Texas that cuts of the old U joints and welds on replaceable types, cost around $500. I changed the center drive shaft support bearing too. No more rumble.

Did you have to remove front drive shaft to replace stabilzer link bars?