700r4 Transmission Issues

[iamscgmeatric]

I have a 1981 Monte Carlo.. 350 Engine/ 700r4 Trans.. When I start my car it goes in all gears just fine but once I get 1-2 minutes up the street it stops moving & sounds like I’m in neutral.. I’ve added fluid etc.. Do I have to replace the whole trans or is it a fixable issue..?


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[TexasT]

Everything is fixable, though the costs can get steep on bigger probs.
Sounds like a pump prob. As it warms the fluid thins and cant apply the clutches.
Do you have the correct amount of fluid in it? Checked when warmed up and idling?

 

[JayInLA]

Same issue on my 81 Regal V6 231 with a THM 200 3spd. I checked the fluid, warm, idling in park on level ground and the level was literally off the chart. As in not within the hash marks of the dip stick. It was somewhere way way way above on the dip stick itself. I just got the car so I’m thinking the previous owner filled it way too much. Could this be causing the clutches to not engage?

 

[blk7gxn]

I hope you both have easy fixes, but from my own personal experience, when those wonderful GM transmissions are to this chapter in their life, they are done. Its truly amazing how long they WILL last with proper maintenance and fluid and filter changes ANNUALLY. As far as "overfilling" a transmission, it does more harm than good. When you overfill a transmission, the fluid tends to get air molecules embedded into the fluid, making the fluid "frothy" and your clutches like pure fluid, not air and fluid, hence causing premature wear on all the internals not getting the proper lubrication because of the air mixed in with the fluid. Good luck to both of you, hope its a cheap and easy fix !