Transmission Skip/clunk at 50mph

[laredo dude]

I put in a used Transmission in my 96' Laredo,has v-8,quadrac,auto.

Everytime like clockwork when passing about 50mph my tranny will kind of miss or clunk. Seems to be happening when its shifting into OD. BUt when I take the OD off, it will do it around 45mph so it seems to be more of an RPM problem. BUT when accelerate harder, it won't do this at all. It will shift fine and smooth, so I'm assuming this is a vacuum or fluid related issue or electronic? Any thoughts?

[dksob81]

yea I would start with a tranny flush, this will prolly help your problem.

[laredo dude]

Originally Posted by dksob81

yea I would start with a tranny flush, this will prolly help your problem.

When I installed it 2 months ago, I put new fluid and filter in it.

[dksob81]

it may have some gunk built up in the tranny, check the condition of the tranny fluid - should be RED.

[vee-ate]

I'm no expert, but if you read up on the transfer case in your grand, you will find that while it is always in four wheel drive, the trans-case has a front to rear lock up that occurs automatically above 45(est)mph. which engages the frond and rear drive shafts so they move at the same velocity. below 45mph, or under hard acceleration, it dissengages to allow the front, or the rear drive-train to act independantly of one another, allowing better traction at take off or when turning, 4-wheeling, etc.. I am fairly certain that the "clunk" you hear is the trans-case front/rear diff lock-up as you accelerate past 45 mph. as this also happens in my 93 w/ the same drive-train.hope this helps.

[laredo dude]

yeah, that makes sense,,,question is now what to do about it. Seems I need to make an adjustment.

[vee-ate]

you will have to be the judge of that. I don't even know if there is an adjustment. but I wouldnt worry unless the sound or"shift" feels really bad or loud. mine is barely detectable most times. more pronounced under light throttle through 40-50 range.

[msrjeep]

i think what you mean is the tcc lockup. it's the torque converter clutch lockup. it locks your engine rpm to transmission rpm to improve fuel economy. on hard acceleration it won't lock up allowing the engine to rev more. assuming your recent fluid change was chrysler ATF+3 fluid, the next step would be a transmission diagnostic at a reputable dealer or transmission shop.