727 cooling

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Jr90
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727 cooling

Postby Jr90 » Tue Oct 10, 2017 11:08 am

I have an 83 waggy beater that i take offroading a couple of times a year, running 31s but other than that all stock and has 2.72 gears so i know that doesn't help. Are there any tricks to cooling the trans? I already have a "stock" cooler in series with a small aftermarket one but it still starts puking fluid from the bell housing after running a while.

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Nikkormat
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Re: 727 cooling

Postby Nikkormat » Tue Oct 10, 2017 1:26 pm

With only 31's you should be fine as long as you're using low range when you should be. But also making sure you've got a good fan clutch, having good airflow across the rad. As long as you aren't in super hot weather you should be able to hold onto the lower radiator hose. There should be that much temperature drop unless you are really pushing the jeep.
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Jr90
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Re: 727 cooling

Postby Jr90 » Wed Oct 11, 2017 9:10 am

This weekend it was in the 80s, i used low range, fan clutch is tied to stay engaged and i dont have a thermostat, engine temp seemed good. Id been playing a little which it had no trouble with but had to try to pull someone a little when it started leaking. May just have to take it easier and install a gauge for a better idea.

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Stuka
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Re: 727 cooling

Postby Stuka » Wed Oct 11, 2017 9:55 am

There are other reasons it can puke besides getting hot. Have you ever had it serviced? Filter change and such?
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rocklaurence
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Re: 727 cooling

Postby rocklaurence » Wed Oct 11, 2017 10:46 am

Bypass the radiator. I had a Ford Explorer that did this until I bypassed the radiator. I run mine through a cooler [biggest GVW that will fit]. Under normal conditions my trans dont exceed 180 and under heavy load only climb to 210. For me, I dont like the idea of intruducing engine heat into the trans.

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Re: 727 cooling

Postby SJTD » Wed Oct 11, 2017 11:02 am

Bearing in mind that I haven't had an auto since I can't remember when, seems to me if you're loosing fluid from the bell housing you have a leak at the torque converter seal or the front cover gasket???

Maybe caused by a plugged vent? These have vents right or is the dipstick the vent?
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Jr90
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Re: 727 cooling

Postby Jr90 » Wed Oct 11, 2017 2:21 pm

It probably needs a filter change, for some reason i didnt think of doing that, ill probably do that and bypass the radiator before the next trip out. I replaced the seals about 6 months ago and it stops leaking after it cools so i dont think its that but it could be, sound right?. There is a vent and its in the bell housing so im thinking thats the source.

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Tatsadasayago
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Re: 727 cooling

Postby Tatsadasayago » Wed Oct 11, 2017 8:28 pm

I'll add that while bypassing the radiator coil works great for the warm season, it can disable your rig if you operate in cold country. I bypassed the radiator coil and went with an aftermarket cooler, and while running up a pass at -20f the trans literally stopped working due to the cold oil. Cardboard covering the entire core support opening solved the problem.
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Stuka
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Re: 727 cooling

Postby Stuka » Wed Oct 11, 2017 10:32 pm

If you need to run through the rad, run through it first, then a big cooler.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
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Jr90
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Re: 727 cooling

Postby Jr90 » Thu Oct 12, 2017 7:37 am

Im in north tx, cold isn't a big issue here usually. I only run this twice a year in march and october and its trailered to and from there. Its worth a shot to bypass it and see what happens.

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Tatsadasayago
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Re: 727 cooling

Postby Tatsadasayago » Thu Oct 12, 2017 1:01 pm

Jr90 wrote:Im in north tx, cold isn't a big issue here usually. I only run this twice a year in march and october and its trailered to and from there. Its worth a shot to bypass it and see what happens.

Yes, TX shouldn't be a problem. I was stationed at Fort Hood for a while and the coldest it ever got was during an ice storm in 83-84. I doubt subzero temps are going to be an issue for you :P
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Jr90
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Re: 727 cooling

Postby Jr90 » Mon Oct 16, 2017 1:09 pm

Just a thought i had, if i cant keep the 727 cool i have a th400 from a 77 waggy that i could put in which had a qt before. Would that be a better trans? To make it work i would need to change the output and tailhousing correct? Or is there a bolt on dhd tcase that will work?

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Stuka
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Re: 727 cooling

Postby Stuka » Mon Oct 16, 2017 1:31 pm

The swap won't work, as the transfer cases wont swap. Well, unless you want to dump a lot of money into adapters and such.

But a TH400 wont stay any cooler than a TF727. If you have cooling issues with one, you will with the other.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
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Jr90
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Re: 727 cooling

Postby Jr90 » Mon Oct 16, 2017 2:51 pm

I meant swapping any tcase to go behind it, like maybe a later chevy that had a dhd, didnt know if any inputs were the same or not. Thats true about temp, also wasn't sure if 400s would hold up better or not though.

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Stuka
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Re: 727 cooling

Postby Stuka » Mon Oct 16, 2017 3:08 pm

The TH400 is arguably a better transmission, but certainly not worth all the work for your situation.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Stock
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

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Cecil14
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Re: 727 cooling

Postby Cecil14 » Mon Oct 16, 2017 4:30 pm

The transmission is definitely not *causing* your problem. While you might inadvertently address the problem during the swap by fixing something you didn't know was really wrong, as Stuka has stated it is not worth the trouble. You would be way further ahead to address whatever the problem is with your current setup than trying to band-aid it with a trans swap. Odds are you'd end up with the same problem honestly, and then you'd be out all the time/effort/money for the swap and still having problems.


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Re: 727 cooling

Postby 78 Arizona Chief » Tue Oct 17, 2017 8:36 am

If you recently added trans fluid when the trans was thought to be fully warmed up, but actually wasn't, the 727's vent is part of the front pump/cover. If the trans is overfilled and vents fluid out, it will come out the front and appear to be a converter or front seal leak, when in fact it is just venting the fluid below that vent line. Get the trans good and hot then check the fluid level. I wonder if it is just overfilled.
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Jr90
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Re: 727 cooling

Postby Jr90 » Tue Oct 17, 2017 9:28 am

Im hoping it is just the vent, can it get too low just from getting hot and running out of the vent? It was not very hot when i filled it but it was losing what seemed like quite a bit of fluid when it did get hot.


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