steiner43511
12-19-2004, 10:43 AM
this is more directed at someone with a 95 or newer automatic that does some towing. what do you guys tow in? we are not gifted with the ability to use drive instead of overdrive like 94 and older. i know the manual says it is ok to tow in od, but i have also heard not too.
quantum mechanic
12-19-2004, 11:20 AM
The '96 my dad has tows fine in all gears. Open that puppy up intake and exhaust and the engine won't work so hard.
Texas Diesel Guy
12-19-2004, 11:45 AM
Towing in OD won't hurt anything, infact it will be benificial to your transmission, with torque converter locked the tranny makes less heat. What you want to avoid is changing constantly from OD to D and back, if the truck downshifts to pass or go up a hill, either give it plenty of pedal to keep it in D or turn the OD off.
I've been reading here that towing in OD isn't a good idea because 4th gear is the weakest, and the tranny can get too hot. Thus, I do all towing in 3rd. The converter clutch engages even in 3rd shortly above 80kph; you get more engine braking power, the shifts are slightly firmer and converter losses seem somehow lessened so that the transmission feels 'stronger' in general. You won't get downshifts unless you force them, except for the TCC can disengage uphills when RPMs are too low for it.
Recommendation here concerning manual control of the TCC --- to keep it locked uphills --- was not to engage it below 1700 or 1800 RPM because oil pressure in the tranny would be too low to hold the clutch against the plate. I would be running in that range and below at towing speed if I did towing in OD and take the risk of damaging the tranny by a slipping clutch.
Even when towing in 3rd, RPMs are so low that maintaining the European speed limits of usually 80kph is a bad idea. That speed is more or less undriveable (letting aside becoming an obstacle in traffic) because the TCC will frequently engage and disengage at that speed. At 88kph, which is what most of big trucks go, the TCC stays locked MOTT, but it disengages on the slighter hills.
96kph were much better, but that can get expensive unless I get a special permission allowing me to go 100kph, but getting that permission could get me into serious problems with road taxes :(
The size of the tires contributes to the problem. My new tires are a bit larger than the previous ones and might make the problem even worse. A manual transmission would be better for towing in my case.
Anyway, with towing in 3rd, I'd say you are on the safe(r) side.
veggiesuburban
12-19-2004, 10:52 PM
My 95 has a warning label on the door jamb warning agianst towing in OD, it says to tow in 3 .
quantum mechanic
12-20-2004, 09:00 AM
I don't know guys. Towing in 3rd seems like you going back in time the progress seems so slow. OD means 65-70 mph with a steady 8-10 psi on the highway.
CanadianRigger
12-20-2004, 12:36 PM
My stock 95 except for 3" exhaust towed no problem with 35" rubber in OD to near 350,000 km's when my own stupidity took out the head gaskets. Sure when you get in the hills you pull it down a gear but on the open road as long as its not constantly downshifting and jumping in/out of lockup i'd say you can tow fine. EGT gage would be a handy item when towing though, would have saved my *ss.
pfloydncsu
12-20-2004, 01:01 PM
i pull in od all the time, even with a 342 rear. the truck is stronger at lower rpm and as long as you are over 1500rpm, it makes plenty of boost to burn any amount of fuel stock pcms will send to it. if the tranny can take overdrive, it will, if not, it will downshift. if it constantly downshifts, pull it down to D, if it holds od, let her roll
steiner43511
12-20-2004, 04:16 PM
with a 95 and newer, you dont have the option of pulling it down to D. you either have OD or 3rd.