1981 Auto Tranny slippage
Thread Starter
Heel & Toe
Joined: May 2013
Posts: 16
Likes: 0
1981 Auto Tranny slippage
Hi everyone,
The car is new to me (purchased 3/13) I drove it all Summer with no issues. I had no slippage when I put my '81 away for the Winter (upstate NY) in November. Last few times I backed it out of the garage the tranny would stop and then catch. Is this a cold weather thing or a sign of things to come? Should I replace the fluid and filter? The fluid is full and not burnt at all. Any ideas? Thanks.
The car is new to me (purchased 3/13) I drove it all Summer with no issues. I had no slippage when I put my '81 away for the Winter (upstate NY) in November. Last few times I backed it out of the garage the tranny would stop and then catch. Is this a cold weather thing or a sign of things to come? Should I replace the fluid and filter? The fluid is full and not burnt at all. Any ideas? Thanks.
Melting Slicks
Joined: Nov 2013
Posts: 3,451
Likes: 336
From: Greater Cincinnati Area.
As an opener, I'd change the fluid and filter.. Mainly because I'd have the pan off anyway, to make sure the filter is tight and it is sealing up good.. (So you're not sucking air over it and getting cavitation)
I'd replace the modulator and the clean the modulator valve.. Make sure it moves without restriction.
Let it run and reach full operating temperature before testing again.
I'd replace the modulator and the clean the modulator valve.. Make sure it moves without restriction.
Let it run and reach full operating temperature before testing again.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Its more likely a 32 year old car thing.
Checking the pan for the remnants of the clutches may or may not net you any new info, PO probably had a new filter in there so might not be much clutch material left.
Tranny conditioner might get you a little more down the road, the seals get hard and don't seal on the clutch pistons, so they slip.
Be ready for a rebuild or replacement.
If you can do it yourself, a 200R4 is a way better tranny, 4 speeds with Overdrive and a better overall gear ratio. I built mine for around $1k with all the fancy parts inside, new cables and shifter adaptor/indicater. Got a CD with step by step, it was actually pretty easy.
Checking the pan for the remnants of the clutches may or may not net you any new info, PO probably had a new filter in there so might not be much clutch material left.
Tranny conditioner might get you a little more down the road, the seals get hard and don't seal on the clutch pistons, so they slip.
Be ready for a rebuild or replacement.
If you can do it yourself, a 200R4 is a way better tranny, 4 speeds with Overdrive and a better overall gear ratio. I built mine for around $1k with all the fancy parts inside, new cables and shifter adaptor/indicater. Got a CD with step by step, it was actually pretty easy.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
I suspect the fluid is low in the transmission. It should be set when the engine is up to temp AND the tranny temp is up to temp (you have to drive it some to get that done!). It also needs to be checked with the transmission in DRIVE range [parking brake ON and/or chocked tires].
When the fluid gets cold, it shrinks in volume, so it could be LOW when cold and cause the slipping condition. But, as it warms and increases volume, it might function fine.
When the fluid gets cold, it shrinks in volume, so it could be LOW when cold and cause the slipping condition. But, as it warms and increases volume, it might function fine.
