Thunk (not the past tense of Think!)

[Whoru465]

OK, here's the scenario- ususally between 0 and 20mph:


From a stop (or even rolling) accelerate.
Lift off of gas to coast.
Transmission shifts with a thunk/shudder.
Then continue driving with no problems...

Now this happens a lot I've noticed recently. It's annoying in traffic where I accelerate to move 20ft and I'm already off the gas for a moment when the tranny clunks into the next gear. As this happens on the 1-2 as well as the 2-3, I'm thinking there might be some play in the driveline and not necessarily a transmission issue. I was wondering if this is a common thing. Theres never any thunk/shudder on shifts during acceleration, only once you get into the stop/go situation. Thanks

[Mr. Pockets]

I'd check the tranny mounts. The rubber parts can crack and separate from the metal parts, which means the tranny can move around a little.

Of course, even if it is bad, the rear mount may not look any worse for the wear until you take it off and it comes out in a couple pieces.

My tranny at times, looks for a gear. The TPS changes things electrically, while brake band adj. tightens or loosens mechanically. These are the easiest adj. you get. Altho the brake band isn't that easy. Anyway, it's a start.

[Whoru465]

Thanks fellas. Good point Peach. I have had an underlying suspicion that my TPS is on its way out anyhow. Ive been having odd acceleration issues as well. I can't locate any of that contact cleaner to dissasemble the damn thing and clean it. I'm going to take a look at the mounts and scratch my head as I contemplate removing and cleaning the TPS

[svx_commuter]

My SVX has always had a clunk when shifting from 1st to 2nd for the past 130k miles. My 91 Legacy has done the samething for the past ah 140k miles also. I think it's not a problem as long as the car keeps on moving. I also think Lucas transmission treatment is worth the cost. Both cars shift smoothly between all other gears.

[rmjjensen]

I've noticed the same thing - low RPM shifts from 1-2 are extremely quick and makes the thunk

But - I think it's just because my tranny resistor is unplugged ....I noticed the trans shifts are longer 1-2 with it plugged in but no thunk.

Is your resistor plugged in or not? ....I really hope i don't need a mount

[Whoru465]

Its worse with the resistor unplugged (thats why I plugged it back in ) I hope I don't need a new mount either, I just fixed the exhaust and have not want to take it out again...I still think the TPS is causing the issue. At low stop and go speeds it seems to give an erratic signal...I really must get around to cleaning it, or hitting it with a large hammer...

[Earthworm]

Not only will the worn tranny mount cause this clunk but so will the mounts for the rear diff if they are worn.

I know mine are worn and I can induce a clunk if I let the clutch out too quick.

[LarryIII]

Whoru,

The "thunk" that you hear is the Red Sox falling down again. It usually happens in October when the weather turns cold.

Seriously, try the easiest things first.

1) Check the reisitor ohms.
2) Check & tighten the bands (if req'd.)
3) Check the tranny and rear diffy mounts. When checking the mounts, please be safe. use good jack stands or ramps before you get under the car. Good Luck.