Transmission sleeping??

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Mexican

Well-known member
Joined
Apr 11, 2015
Messages
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Location
Oklahoma
My Car
71 mustang grande
Yes, my transmission falls a sleep and forgets to enage when i put the car on drive, changed the trans oil a few months back, including filter, it slips for a second when i first start the car and engages fine after it warms up, is my trany about to kick the bucket???:-/

 
Yes, i have checked the level and yes it did it before the oul change, cant remember the oul brend.

Took it on a 150 mile trip around surrounding towns with no problems at all, only when is cold.

 
could be a few things.

first how long ago or miles ago was the transmission rebuilt, or has never been rebuilt?

when you changed the trans fluid and changed the big bottom filter on the valve body

there is also a smaller snap in filter on the side of the valve body. these can get all chunked up, they do not make replacements for the smaller filter you are suppose to snap it out and clean it,,, however my memory is a little foggy i think you have to actually drop the valve body to get to that smaller filter.

what was the condition of the trans fluid you took out?

was the pan bottom full of clutch material?

what fluid did you use Type F?

low pressure most likely the cause.

1) torque converter is going

2) pump worn damaged

3) Seals inside the trans have gotten hard and are leaking pressure.

4) junk inside the valve body.

5) fluid getting too hot,, issue with trans cooler.

more will depend on the last time that transmission was internally serviced most of the stuff on the list means trans has to come out for rebuild.

when the transmission is cold the fluid is a little thicker, so it does not leak pressure as much through a bad seal. once warmed the fluid is thinner and it will leak through a bad seal.

pressure drops and the clutch pistons can no longer move or hold the clutch packs against the pressure plates and the trans won't shift correct or may be lazy to put in gear.

over time and heat, the seals shrink and get hard or wear out there are about 25 large seals inside the transmission.

when you use something like Lucas Transmission helper it makes the trans fluid thicker it also has some seal swell in it to try and keep the internal pressure leaks in check. the stuff works very short term, long enough to sell the car to the next guy that has to rebuild the transmission

 
could be a few things.

first how long ago or miles ago was the transmission rebuilt, or has never been rebuilt?

when you changed the trans fluid and changed the big bottom filter on the valve body

there is also a smaller snap in filter on the side of the valve body. these can get all chunked up, they do not make replacements for the smaller filter you are suppose to snap it out and clean it,,, however my memory is a little foggy i think you have to actually drop the valve body to get to that smaller filter.

what was the condition of the trans fluid you took out?

was the pan bottom full of clutch material?

what fluid did you use Type F?

low pressure most likely the cause.

1) torque converter is going

2) pump worn damaged

3) Seals inside the trans have gotten hard and are leaking pressure.

4) junk inside the valve body.

5) fluid getting too hot,, issue with trans cooler.

more will depend on the last time that transmission was internally serviced most of the stuff on the list means trans has to come out for rebuild.

when the transmission is cold the fluid is a little thicker, so it does not leak pressure as much through a bad seal. once warmed the fluid is thinner and it will leak through a bad seal.

pressure drops and the clutch pistons can no longer move or hold the clutch packs against the pressure plates and the trans won't shift correct or may be lazy to put in gear.

over time and heat, the seals shrink and get hard or wear out there are about 25 large seals inside the transmission.

when you use something like Lucas Transmission helper it makes the trans fluid thicker it also has some seal swell in it to try and keep the internal pressure leaks in check. the stuff works very short term, long enough to sell the car to the next guy that has to rebuild the transmission
Thanks!!, i did not replaced that small filter, also i have no idea when the trany was last worked on, i guess i will drive it until it quits and then have it rebuilt, is there anything i can do to beef up the transmission in case i want to add power to the engine down the road?

 
it depends on whats in the transmission now but, if the transmission is original to the car and a C6 or C4 then you have many options

a FMX you cannot do very much with.

the C6 depending on machining work done can hold more clutches making the transmission stronger. a stock C6 original to 71-73 mustangs only had 3 clutches per pack.

later C6 had many more packs, up to 5 stock in the forward and direct drums and 7 in the main body. you can change out drums for later models and increase the clutches later transmissions were also anti clunk which can be removed to pack more clutches.

the main body of the transmission would have to be machined or replaced to add more clutches.

the clutches themselves come in grades for performance, the 2ns gear band can be upgraded to a wider belt for more grabbing power.

the planetary gears can be changed out for lower ratio or you can take truck planetary gears which have 4 gears instead of 3 to hold more power.

valve bodies can be modified or replaced for more performance or if you want a manual shift option.

there are higher stall torque converters that will allow you to dump more power to the rear wheels.

servos and levers can be upgraded for more grabbing on the 2nd gear band.

you can make the shifts so strong and abrupt that you can give yourself whiplash.

you can spend 10K on a c6 modifying it.

 
Haa ha, 10k is a little out of my league, it is a c4 transmission and the car is a coupe so not worth dumping 20k on a 5k car, probably will just find a good transmission shop and have it rebuilt when it finally quits:)

 
It's not dead; It's not sleeping...it's pining for the fjiords!

 
Put some lucas oil transmission additive in it and hope for the best:D

I have had good luck doing this on worn out transmissions and was able to keep them alive for a while after using this product.

 
just fyi i used lucas oil transmission additive, it stopped up the leaks and i got about 1000-2000 miles more out of the transmission before it blew up and i had to rebuild it anyway.....

basically if you are selling the car put the lucas in otherwise set 800-1000$ to the side for a junky trans rebuild and 1500-2000$ for a REALLY good rebuild.all the trans shops are out to screw you as well. how would you even know what they put into the transmission unless you sat there next to the guy like a hawk. they skimp on everything figuring since it is an old not daily driver car that by the time the trans blows up it is 4-5 years and 500 miles later and good luck suing them for shoddy work. those paper guarantees they give out with the rebuilds are toilet paper.

I got screwed by the worst transmission place in NY i have documented evidence of the shoddy work they did when i paid for a complete rebuild,,, so i ended up rebuilding my trans and 3rd member myself which lead to these threads i started.

rear end

http://www.7173mustangs.com/thread-how-to-rebuild-a-ford-9-inch

http://www.7173mustangs.com/thread-how-to-rebuild-a-ford-9-inch-part-2

transmission

documentation of the worst trans shop

http://www.7173mustangs.com/thread-the-curse-of-the-blown-transmissions-strikes-again?pid=236547#pid236547

http://www.7173mustangs.com/thread-the-curse-of-the-blown-transmissions-strikes-again

http://www.7173mustangs.com/thread-c-6-transmission-master-kits-to-stay-away-from

http://www.7173mustangs.com/thread-lets-talk-about-c6-servos-and-levers

http://www.7173mustangs.com/thread-help-me-find-a-torque-convertor

 
Not planning on selling the car, in fact it ia at the paint shop now, they are replacing some cancer and getting it ready for paint, my wife and daughter both love the car so i will keep it for now, i was told and read in here somewhere that one could put a newer transmission on this car, like from a fox body, how hard would be to do that? of course i would have to pay to have it done, my mechanic abilities end at replacing an alternator:(

 
Not planning on selling the car, in fact it ia at the paint shop now, they are replacing some cancer and getting it ready for paint, my wife and daughter both love the car so i will keep it for now, i was told and read in here somewhere that one could put a newer transmission on this car, like from a fox body, how hard would be to do that? of course i would have to pay to have it done, my mechanic abilities end at replacing an alternator:(
I am doing a T5 conversion on mine right now from an FMX. I am just at the beginning stages, IE Mounting the clutch pedal, but I am documenting everything and will post a thread. It really is not crazy difficult from what I understand. I have no training as a mechanic but I have just learned by doing. Biggest thing I can tell you when taking on a project is research prior, take lots of notes and photos while doing it and don't get frustrated.

 
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