I am hoping you guys can help. The trans in my truck lost reverse friday morning as I was leaving on my annual Snaggin' trip for spoonbill. I baacked out of the garage, noticed it didn't engage all the way, checked the fluid and all was well. Went to Wallyworld to get fishin liscense, came out and started to back out, same thing, only a little worse. Went to gas station to fill up. Started up and tried to back up, and barely got out. Went home and pulled into shop, checked fluid, checked proper linkage alignment, all was good. Went to back out of garage, and nothing. On the way home I made sure that 1st, 2nd, and3rd all worked fine by manually shifting. I gave it hell through all 3 gears and it never slipped once, and shifted perfectly. I am thinking the servo piston or the actuating arm has gave up. Any other ideas before I proceed?
727 trans problem
- Thread starter GUP
- Start date
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fishy68
Tyr Fryr's Inc.
Sounds like your gonna have to drop the pan to check things out. Check the rear band adjustment first. You didn't mention what year trans. you have but most are backed off 2 turns after you torque it to 72 inch lbs. If the band adjustment was close it is possible the problem is in the rear servo or linkage. If no problem is found with any of these items the problem could even be in the front clutch. Either way first step is to drop the pan and inspect things. Good luck.
I dropped the pan, collected all the parts from the reverse servo laying in the pan and pulled the trans. Looks like the servo cup cracked and broke. Should've pulled the pan at the first sign of trouble. Then I could've just bought a steel servo cup and replaced t6he aluminum one and been on my way. Oh well.
fishy68
Tyr Fryr's Inc.
Bummer. I've heard of them cracking/breaking and I've rebuilt several tq's but I've actually never seen one broken or cracked. Why did you pull the trans? You can replace the rear servo piston assy. without pulling the trans. Admitedly the rear band strut isn't real easy to get back in but it can be done.
BTW: Don't buy Sonnax crap. I recently bought a Sonnax Billet rear servo piston for the first time for a 727 I was rebuilding because their price was good. It was JUNK. It was made about .030 too small (this was measured against the old piston that was probably worn down some) and was so sloppy in the bore when I put it in it would **** sideways real easy.
BTW: Don't buy Sonnax crap. I recently bought a Sonnax Billet rear servo piston for the first time for a 727 I was rebuilding because their price was good. It was JUNK. It was made about .030 too small (this was measured against the old piston that was probably worn down some) and was so sloppy in the bore when I put it in it would **** sideways real easy.
It was time for a rebuild anyway. I figured I was this far why not get it over with. The guy I had rebuild it says the governor was turned up too far, and this may have caused it to crack and break. I don't know if that's true, but at any rate, I am bacvk on the road again!!!
340mopar
Sorgermotorsports
I would be leary of your tranny guy. A governor controls the shift point at wide open throttle (WOT) so I don't see what it has to do with putting your truck in reverse. I may be wrong, (it has happened before). I have not done many 727 transmissions (probably because the are so tough) but have done a ton of GM 350 & 400 transmissions, I am assuming the governor will act the same on a Mopar trans as it does a GM trans. I have not found a trans yet that the governor does not control WOT shift point.
fishy68
Tyr Fryr's Inc.
I might be leary of him too. First of all there is no way to "turn a governor up" on a torqueflite. And second it has nothing to do with the reverse servo. But hey if it works correct now he must have done something right.
Actually the reverse servo breaking is something that just seems to happen once in awhile on torqueflites for no explained reason. Maybe a hairline crack in the servo piston from day one?? Who knows??
BTW 340Mopar what the heck is so tough about a torqueflite??? I've rebuilt 350 and 400 turbo's and 727 torqueflites and torqueflites are waaaay easier to work on in my opinion. Not that turbo-hydramatics are hard or anything but 727's have to be the simpleist of the bunch. I generally do one in about 2/3 of the time it takes me to do a GM and I've done way more GM's.
Actually the reverse servo breaking is something that just seems to happen once in awhile on torqueflites for no explained reason. Maybe a hairline crack in the servo piston from day one?? Who knows??
BTW 340Mopar what the heck is so tough about a torqueflite??? I've rebuilt 350 and 400 turbo's and 727 torqueflites and torqueflites are waaaay easier to work on in my opinion. Not that turbo-hydramatics are hard or anything but 727's have to be the simpleist of the bunch. I generally do one in about 2/3 of the time it takes me to do a GM and I've done way more GM's.
i agree with fishy68 first transmission i ever tried to rebuild was my 904 and the second one was a TH350chebby transmission and the mopardesign is lots easier to work on i actualy managed to rebuild the 904transmision way quicker than my chebby transmission and both of these transmissions have served me troublefree since then, ok the 904 has been looked thru after that but that is because of the life it lives and has nothing with breaking parts or bad function to do;)
340mopar
Sorgermotorsports
What I meant by tough was they Last not that they were hard to work on. I would much rather rebuild a Torqueflite than a GM trans any day of the week.fishy68 said:
fishy68
Tyr Fryr's Inc.
340mopar said:
Oh I got what ya mean now 340mopar. That's one of those words that can be used 2 different ways. Sorry about the confusion.
340mopar
Sorgermotorsports
No sweat, one of the problems with communicating with a key board is you don't have the tone of voice or facial expression thing so it is easy to misinterpet a words meaning. Oh yea, you have the spelling thing too.fishy68 said:
but now i get it -
