Cold 727 slipping. Any ideas?

[413]

If that 727 was in use with no filter that’s really bad and it’s time is limited. How long was it run like that? Too long I can tell you.

What year, engine, and car is this in?

Seal conditioners only work on lightening your wallet. They don’t fix anything. You can usually take apart the trans and find the worn seals or seal surfaces that a conditioner would have zero effect on.
I agree true part throttle kickdown is on 1971 and up.

 

[mopar440]

Try it this morning?

 

[mopar440]

I was gonna say converter drain back. What happens if you put it in nuetral, rev it to 1200 for 5-10 seconds, does it act up?

Also, what state you in? I'm in Minnesota. Heck, I'd rebuild it for 400. That would include a few bushings if needed, I'd even give you a warranty! I'd even let you drive my Charger that I rebuilt the trans in. It shifts so nice, most people can't tell when it shifts!

 

[1970cat]

replace a quart of fluid with this

available at most parts stores. it's cheap and it works.

 

[CBODY67]

From what I've read, the "seal sweller" additive will "swell" things about 5%, if that much. Sometimes, just making them a bit softer helps, I suspect. Getting a reputable brand might be important as I suspect there are still some "mouse milk" additives around.

I'm wondering if the "no filter" was the result to help things along due to other worn internals?

CBODY67

 

[70bigblockdodge]

Rebuild yourself atp kit is like $75 band is $25, low reverse band just reuse if it is not peeling. Make sure you flush cooler and lines.
They are easy to rebuild and you have a whole forum to ask questions.

 

[CBODY67]

Flushing the cooler and lines is imperative for any automataic transmission, for best results. The cooler/lines will have the same contaminated fluid that's in the transmission, which when circulated to the rebuilt item, could damage it very quickly. Cheap insurance!!

Enjoy!
CBODY67

 

[WissaMan]

Flushing the cooler and lines is imperative for any automataic transmission, for best results. The cooler/lines will have the same contaminated fluid that's in the transmission, which when circulated to the rebuilt item, could damage it very quickly. Cheap insurance!!

Enjoy!
CBODY67

They can also be blocked so much that they don't allow proper flow through the cooler.

 

[rkrochen]

They can also be blocked so much that they don't allow proper flow through the cooler.[/

Don’t forget about getting the converter flushed or rebuilt at the same time.

 

[Joseph James]

If that 727 was in use with no filter that’s really bad and it’s time is limited. How long was it run like that? Too long I can tell you.

What year, engine, and car is this in?

Seal conditioners only work on lightening your wallet. They don’t fix anything. You can usually take apart the trans and find the worn seals or seal surfaces that a conditioner would have zero effect on.
I agree true part throttle kickdown is on 1971 and up.

It’s a 68 Sport Fury with a reman 383. I have put about 10k miles on it so far. I drive to work and back about 24 miles a day. Transmission has been good up to this point. It has had several fluid changes so far.

I have NO kickdown. Not even at WOT. The fact the filter was missing when I bought it (2018) makes me wonder if someone screwed around with the valve body, or lost parts.

Prior to my buying it, it sat in an impound lot for a while. It was sold to the guy I got it from who wanted the motor for a B body. Fortunately for me, the motor was shot and the guy had to sell it.

I manually shift to 2 when I get on the interstate. Going back to D, it takes a second or two to hit 3rd. The harder I push it the longer it takes. Other than morning slip it seems ok.

I did go through all gears and have let it sit in neutral for a couple of minutes before I drive it. That seems to help for now.

Likely I will have transmission guy do it. He says he can change rooster comb so I have reverse lights off of 69+ NSS. I will probably pick up the better valve body and have it put in. I just don’t have time to learn and rebuild it myself. List of honey do’s and my upper control arm bushings need immediate replacement. They are worn and I am eating the inside of the passenger tire.

 

[70bigblockdodge]

If you change the valve body you will change the rooster comb.
Do you have a kickdown linkage?

 

[mopar440]

It’s a 68 Sport Fury with a reman 383. I have put about 10k miles on it so far. I drive to work and back about 24 miles a day. Transmission has been good up to this point. It has had several fluid changes so far.

I have NO kickdown. Not even at WOT. The fact the filter was missing when I bought it (2018) makes me wonder if someone screwed around with the valve body, or lost parts.

Prior to my buying it, it sat in an impound lot for a while. It was sold to the guy I got it from who wanted the motor for a B body. Fortunately for me, the motor was shot and the guy had to sell it.

I manually shift to 2 when I get on the interstate. Going back to D, it takes a second or two to hit 3rd. The harder I push it the longer it takes. Other than morning slip it seems ok.

I did go through all gears and have let it sit in neutral for a couple of minutes before I drive it. That seems to help for now.

Likely I will have transmission guy do it. He says he can change rooster comb so I have reverse lights off of 69+ NSS. I will probably pick up the better valve body and have it put in. I just don’t have time to learn and rebuild it myself. List of honey do’s and my upper control arm bushings need immediate replacement. They are worn and I am eating the inside of the passenger tire.

Make sure he takes care of the converter drain back problem. I haven't researched how to do that, I just do the nuetral thing

 

[Joseph James]

If you change the valve body you will change the rooster comb.
Do you have a kickdown linkage?

See, I know zip about the transmission.

Yes. I have set kickdown linkage per FSM.

 

[70bigblockdodge]

Have a Trans-go kit put in valve body it has a mod that charges converter in park. Make the shifts RV /towing if you do not want really firm shifts

 

[Gerald Morris]

While you have the pan off, also check the band adjustment, a lot of transmission shops have forgotten this lost art as most modern transmissions have no adjustment.

Dave

WORDS OF WISDOM! I thank God I found my neighborhood tranny shop, owned by a fine middle aged octogenerian, with his kid sidekick in his 70s. Hermann Rousch built the best automatic transmission I've ever driven in 43 years behind the wheel. This experience includes stuff from Jaguar XJ6s, to Ford FMX, C4, C6, (Borg-Warner) Ford-O-matics, Chevy Hydramatics, TH350s, 400s , Torqueflite 727s and 904s (w /6) and some manual trannies not quite comparable in this assessment.

Never hire mechanics young enough to be your offspring. Best if you're young enough to be theirs.