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Discussion Starter #1 (Edited)
I have a 700r4 in my 60 & today it developed a bad leak from what appears to be the 2-4 servo cover. I cant duplicate the leak but while I'm driving it will all of a sudden leak onto the exhaust & leave a smoke screen & oil trail on the raod behind me, then just as quick as it starts it stops. not sure if it is gear, rpm or throttle dependant.

Anyone have experience with a leak like this?

I can't tell exactly where the leak is coming from since the ATF gets sprayed all over the transmission, but from what it looks like its the 2-4 servo cover. I cannot duplicated the leak while stationary in park, neutral or in drive.

any help would be much apreiciated.

Edit:

oh yeah, it has a howell lockup kit installed with a 4th gear pressure switch.

one more thing, since I've owned the truck it has always hunted in & out of overdrive at light throttle accelleration, with he leak it just got much worse. If I drive in 3rd its no problem only if shifted into OD. could the problems be related?
 

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i'd say it's overheating and then blowing the excess fluid out of the vent, which is located at the top of the case right above the servo cover, but not leaking from the servo cover itself. not uncommon. make sure you're using the proper dipstick.
couple of questions:
how are you checkinbg the fluid level? with the engine running or not?
how are you keeping the trans cool?
and what size tire and what gearing are you running?
what rpms are you doing at freeway speeds; 65mph?
 

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Discussion Starter #3 (Edited)
Thanks georg I was hoping you'd reply :D

The b&m temp gauge shows about 130D when its happening. I'm running the largest tru-cool cooler & its happens @ road & highway speeds although it probably started when my wife was driving on the highway @ 60mph. (I got a frantic call that the truck was on fire :)) then it reoccured about every 1/2 mile for about 3 miles at speeds less than 40mph, in 3rd or less & nuetral with the engine off on downhills.

The gauge is installed into the feeder line for the cooler.

I'm running 35's & 4.88's

@ freeway I'm aroung 1500-1800rpms IIRC

unfortunately I can't see the vent to see if that where the fluid is coming from & I dont think the trans feels overly hot to the touch.

I have not checked the level in about 5000 miles but I do it just how it says on the dipstick, running & in park IIRC

I need to clean it well & then drive thru the neihborhood & see if I can get it to do it again to find exactly where its coming from.

my guess is that it lost about 1.5 qts overall since it started & it has yet to expierence any slipping.
I need to check the level but I brought it home & parked so far.

Fawking cruisers :flipoff2:

Oh yeah... Thanks for the reply
 

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How many miles do you have on it?

I'm not a auto tranny expert, but when it is OD, the pump is turning slower because of lower RPMs. Therefore the fluid is staying in it longer and gets hotter.
 

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warpdriv said:
How many miles do you have on it?

I'm not a auto tranny expert, but when it is OD, the pump is turning slower because of lower RPMs. Therefore the fluid is staying in it longer and gets hotter.
no offense jeff, but whoever told you that is way full of crap! actually, screw the no offense part! tell him he's full of it! :flipoff2:

the pump in an automatic transmission turns at the same rate as the engine, and is vegulated via a valve to produce a certain amount of pressure, normally between 80-150 psi. if it was'nt regulated, it'd blow a hole right thru the case.
the hottest part of any transmission is the torque converter, especially when you're driving down the road in 4th gear with the converter not locked up, since then it's still slipping and has the most load on it. the transmisson will run the hottest under these circumstances since not only the converter is running hot, but it's also running thru a set of planetaries to achieve overdrive, creating more heat.

now back to the problem at hand. i would find the vent tube on the trans, which is located right at the top of the case. might be tough to get to from underneath, but if you go thru the original transfer case shifter hole in the floor, you should be able to see it. i would attach a piece of fuel line to the plastic vent tube on the trans and run it to a 2 liter soda bottle or something else that can hold some fluid. mount that under the truck somewhere after thouroughly cleaning the undercarrige and then start driving it. if the fluid comes out of the vent, the bottle will catch it and should help determine the problem. make sure you drill and extra hole in the top of the bottle or leave some sort of vent, otherwise it's gonna try to "vent" on it's own and blow either the lid or the fuel line off.
a transmission vent normally pumps out fluid when the level gets too high. that's either due to too much fluid in the trans or to the fact that trans fluid expands when it heats up, thereby increasing the volume. when a trans vents' they normally pump out a quart or more. it will discharge the fluid in a hurry, creating a major mess all over the undercarrige, including the exhaust. pretty cool smoke show.
i find it peculiar that you have 5k miles on it and the problem has never occured before. have you checked the t-case fluid level? i would certainly do so. might be pumping fluid into the trans for some reason.
try the bottle trick, then we'll go from there. :)
 

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Discussion Starter #6
about 80k since the last rebuild-still runs real strong.

with the OD there is a lockup converter so when in OD with the converter locked is runs WAY cooler. I'm pretty sure its not overheating but I'll drive it when I get a chance to see if it will do it again.
 

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Discussion Starter #7
good idea on the vent.... but last time I had the trans out I noticed the plastic tube was broken off flush with the case :( Any way to fix this? I'd like to extend it higher since I do do some deep water over here from time to time. that damn t-case boot is a pain to get back on.

I'll check the t-case level but I have the AA adpater from my split case & it would have to travel thru 2 seals. I'll check it though.
 

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OD and lockup are 2 completely different functions of that trans. just cause it's in OD, does not mean that it's also in lockup or vise versa.
od is 4th gear, pretty self explanatory.
lockup is a function of the converter. basically, the converter has a "lock-up clutch" designed into it. this clutch is hydraulically applied as long as certain criteria are met and eliminates all slippage in the converter, bringing the engine rpms down a few hundred and reducing the heat being produced in the trans. and just like OD, it's another invention brought on by the gas-crunch in the late 70s, early 80s.
for the conveter to go into lockup, these conditions have to exist:
the trans has to be in 3rd or 4th gear
the vehicle has to be traveling above roughly 40mph
vacuum has to be above a certain point
brake switch can not be activated
lockup solenoid has to have power going to it
 

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Discussion Starter #9
yeah, I'm just too lazy to type my understanding of it. from what I read (I forget where), the lockup was designed mainly to cool the trans when in OD. Lock ups RULE!! you can watch the tach for the converter to lock up. as soon as you load it it unlocks. for some reason (maybe the howell kit) mine only locks in 4th gear.
 

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the howell kit uses a 4th gear pressure switch so it can only lock up in 4th.

fixing a broken vent tube in a 60 could be challenging. you have to use an eazy out or something similar to get the old plastic tube out, then tap in a new one (available at the dealer or any decent trans shop for a buck or 2 ) and then use a hose clamp to attach a piece of fuel line, or better yet, trans cooler line (soft).
if you want to be really tricky, you can tap the case for a fitting, but on a 700, it's kinda tricky, even with the trans out of the car. much easier to do on 350s and 400s.
 

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Discussion Starter #11
thanks.. sounds like its going to be fun :D

whats tricky about tapping the case, trying to keep filings out of the trans? wish my dumbass would have done it while it was out of the rig.

unfortunately there are no good trans shops overhere.. I'll get one from the dealer.

Thank you VERY MUCH for your help.... I'll report back when I know more info on the problem!!
 

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vent tube delco # 8633408

the problem with tapping a 700 case is the fact that the hole does not go straight into the case, but at an angle. on top of that, the bottom edge is almost tough to work with due to it's location. hard to get a fitting on there and then use a socket to tighten it without grinding the case, and i'd be really careful doing that; not recomended.
 

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Thanks for clearing that up orange. :smokin:

Help me understand though (no thread hijack intended), so does the flow of the fluid decrese/increase relative to engine rpm?

TIA,
 

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warpdriv said:
Thanks for clearing that up orange. :smokin:

Help me understand though (no thread hijack intended), so does the flow of the fluid decrese/increase relative to engine rpm?

TIA,
nope. the regulator valve in the pump controlls the pressure and keeps it fairly constant, although at high rpm's it will increase some.
 

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Discussion Starter #15
Found the problem!!! turns out my vent tube was not broken off (I cant remember why I thought it was ??) so I wrapped it with what I had available (toilet paper & masking tape :D ) & took it for a spin. 1/2 mile later & in 4th gear I could hear spraying & see a trial behind me :( so I stopped & had ATF all over & could still slightly see it oozing form its hole. its coming from the 4th gear pressure switch right in the plastic portion where the wires attach, so it looks lke the POS howell pressure switch blew (lasted a good 90k miles)

Where can I get another one of these? any better way to do the 4th gear lockup only without a pressure switch? I have a feeling that it could be what is causing the 4th gear hunting under low throttle acceleration since sometime at highway speeds on a slight grade the lockup with rapidly lock & unlock unless I give it enough throttle to downshift to 3rd. any help you guys (Georg) ;) could give me i'd apreciate it!!!
 

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is it on the passenger side of the case right by the fillertube? can you take a pic and e-mail it to me?
 

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Discussion Starter #17
it is tapped into the 2-4 servo cover. I just got one for $7.85 from the only trans shop in town & installed it.... its fixed.... pics to follow!

its part of the Howell 4th lockup kit... the guys at the shop had never heard of one like this.
 

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that's really weird.

normally, the 4th pressure switch is on the valve body in the pan. :confused:

i've installed a few howell kits and have never seen that setup. funky to say the least! :shaking:
 

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Discussion Starter #19
georg,

Here's the pics you asked for:


the old switch on the package of the new switch (the new switch was much smaller):



the switch as installed:



the howell instructions page 1:



page 2:



this must be some half assed kit huh?
 
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