Thanks re: 85 Chevy

[lonestarjeff]

Thanks everybody for the comments & thoughts on my tranny fluid-spittin' truck. When I'm back up at the farm next week I'll check the vent tube.

I don't think its a overheat problem since it started the spitting only 5 min. into the trip....no towing envolved.

Jeff

 

[D Squared]

I don't think it is overheating but it takes me back. On the 90s they had some overheating issues when towing. The manual said you could tow in OD. First thing they did was send out a new page for your manual that said you couldn't. Then when it overheated the fluid would boil out the fill tube. So they sent me a new fill tube with a double o-ring seal on it. Then it would boil out the vent tube that was right on top of the muffler. So there was a recall to relocate the vent tube to the other side. Funny thing was that they were never concerned with fixing the problem, only not getting sued for burning your truck down (some did). The end result was that all trucks come with a trans cooler now. Check your vent tube

D2

 

[Brian Jasper co. Ia]

Thats interesting. Being a trans tech at a Chevy dealer, I recommend never towing in overdrive due to fewer clutch plates in high gear, the stator support wears and you loose hydraulic pressure in the forward drum, then theres the overheating factor because the TCC either never comes on due to the load, or it's constantly coming in and out and wipes the clutch in the converter.
The one exception is the Allison trans. On the early ones you can't disable overdrive without disabling 4th which is direct. The 6L80 hasn't been out long enough to see how they stand up.
Unless you have an Allison trans, don't tow in overdrive unless the load is light enough that the TCC stays on going up hills.

 

[D Squared]

At the time I was towing a boat and trailer (combined weight 3000 lbs). Even after all the "fixes" after about 100 miles I would pull off the expressway and the back of the truck and the front of the boat were cpvered with trans fluid. I never had any problems with the TCC even in OD. I have a Dodge now and on a couple of hills in KY when I tow my camper it wants to kick the TCC in and out unless I change my speed.

 

[Bill M (OH)]

I tow 7 tons (5th wheel) in OD with my Ford 350 diesel and have never had a problem yet ('bout 40K miles towing). I keep hearing I'm not supposed to do that, but the D thing uses enough fuel in OD to break the bank, so I guess I'll keep doing it until....

 

[Bob]

WHAT tranny are you talking about that has "less clutch plates" in overdrive?

LIKELY, he a has a 700-R4.

In third, the forward and direct clutches are engaged.

In forth, the band engages as well, but the forward and direct clutches remain engaged.

So HOW to you figure there's less clutch plates carrying the load in OD, than there is in third, when the EXACT SAME clutches are in use, the only difference being that the band also comes into play in OD?

OR, am I thinking backwards, AGAIN, LOL!