transmission smooth, but clunks when first accelerates

[xirdneh]

The connection between the differential and the automatic tranny is a strange looking part that the FSM calls a Governor
if that thing is going bad due to its splines being worn it could cause the clunk
the diff shaft and tranny shaft are both splined steel and they are almost butted together
the governor slides over both shafts connecting them together
if i remember correctly the governor is aluminum
if that is your problem it will eventually strip it splines
you will be able to drive the car but only while in 4wd

i hope that is not your problem

[Mark]

The connection between the differential and the automatic tranny is a strange looking part that the FSM calls a Governor
if that thing is going bad due to its splines being worn it could cause the clunk
the diff shaft and tranny shaft are both splined steel and they are almost butted together
the governor slides over both shafts connecting them together
if i remember correctly the governor is aluminum
if that is your problem it will eventually strip it splines
you will be able to drive the car but only while in 4wd

i hope that is not your problem

That's what happened to mine. It failed when I was driving and I got home in 4wd. I replaced the governor with one from another old transmission. The splines on the "new" one were slightly worn, but I couldn't feel any play when I installed it and rotated it by hand. I was hoping the clunk would go away, but it sounds just the same. I wonder if the shock from the clunking accelerates wear on the splines? The governor on mine was steel, but it must be softer than the shafts since the shaft splines weren't worn at all.

[zachh]

It's is probably too much backlash in the front differential, I'm having that same issue and upon taking my front diff off, there was soon much play between all the diff gears.
Fluid also ran low though and now I'm going to try rexplaining the carrier and pinion bearings.
And getting the backlash within the right amount.

[Mark]

Before I removed my transmission, I pulled the front cover of the differential to check if that was the problem. I rotated the wheels and didn't feel any backlash in the differential and everything looked good. I was actually surprised since I expected there to be some wear. When the transmission was back together I checked for play and it seemed like it was coming from further in the transmission. I don't know how normal that is. One thing I didn't check visually is for wear in the splines of the driveshafts where they go into the differential.

[Petros]

usually the splines do not get much wear, if you have an internal "clunk", something within the trans (likely on the mainshaft) is really wearing out. eventually it will fail and trash the transmission, so best to see if it can be fixed now. or start looking for a replacement trans from a wrecker, or a private party parting out a tercel.

check that the clunk is not coming from: worn front suspension bushings, worn and sloppy CV joints, bad engine mounts. These are actually more common source of a clunk than the trans itself.

[Jonymoto]

Also grab the inner tie rod on the passenger side and move it up and down. If there's play, it means that the steering rack internal bush is worn. I had clunking noise whenever I pushed the clutch in a hurry to change gear (manual trans of course). I replaced the bush and the noise disappeared.

[Jonymoto]

I forgot to mention that my Tercel has manual steering. That's the only version that Toyota sold here. So, I'm not sure what the setup is with power steering. But I imagine it would still have a bush on the passenger side to support the steering rack.

[dlb]

just so everyone's clear, this is an old thread. the OP probably sorted this out quite a while ago.