Hi folks. I want to install a new trans cooler on my 1996 F250 with the 5 speed manual trans. I would like to flush the existing cooler lines when I do this. But I cannot find where they connect on the trans when looking at it and I have searched all over for a diagram of where they are. Can someone point me to them and is there a special tool needed to disconnect them? Thanks, RH

 

To the best of my knowledge the Zf-5 did not have a transmission cooler. The Zf-6 in the 1999 and up trucks had a cooler.

 

Really, that is interesting. Do folks find a way of installing one or is it thought to be not needed? U ask because in all the years of using mine I have not had a problem but yesterday I was trying to back up a grade with 6 tons of gravel in my dump trailer and all of a sudden there was great deal of smoke and I had trouble shifting. One I let the truck sit and cool down I could shift and use as normal. This is why I started investigating overheating the trans. I can't think of anything else it would have been and examining today I could not find anything amiss.

 

That sounds more like a clutch issue; a transmission cooler won't help with that. This is when low range helps.

Not sure what's so "interesting" about a transmission with no cooler. Manual transmission coolers are an exception. The ZF-6 one of the few 20th-Century manual transmissions that had one. I've owned nothing but manuals for 35 years, and have never had one with a cooler.

 

I only said interesting because of the fact I saw so many threads talking about the transmission overheating and installing a bigger trans cooler. My first thoughts too were the clutch but after I was able to drive with no problem and no slipping I was scratching my head and then found all the threads on installing a bigger cooler. I guess I will now examine putting in a new clutch if manual trans do not need additional cooling. I have hauled over 70 tons of gravel in the last couple of weeks with no problems at all then this happened.

 

Is it a 4x4 truck?

 

Yes and what it happened it was in 4wd low reverse backing up a grade with some loose gravel that had been freshly laid previously with me backing up with the same amount of load.

 

The threads you are reading about installing a larger trans cooler are for automatic transmissions.

 

I am aware of that now ...thanks.

 

it really sounds to me like the dual mass flywheel in your truck gave up it's smoke.
it will happen again the next time it gets hot.
my 88 would start slipping after 20 minutes hard driving. after around 45 minutes driving you could come to a complete stop without stepping on the clutch with the trans still in 4th or 5th gear.
let it sit for 4-5 hours and you could smoke the tires off it. until the flywheel got hot and started slipping again.

 

Thanks, I am also now believing it must have been the clutch. Is there a way to really know before I pursue replacing it? Again the truck seems to drive fine without any load on it right now. If it is the clutch it is a pretty expensive repair for me to pay someone to do it. I have never attempted this size/weight of repair as a DIY mechanic. The truck only has 156k miles on it though. I now need to find a good tutorial on doing this big of a job if I am to attempt it myself and it would have to wait until spring because I don't have a shelter large enough for this truck to attempt it inside. Also, any recommendations on a replacement clutch are appreciated.

 

If you are running a stock powered truck I would look into a single mass flywheel and clutch from either LUK or South Bend. Luk makes a terrific HD clutch for cost. Mine personally has gone 220k in a non stock application and has surprised me to say the least. Southbend also makes a solid clutch and is equally priced:

South Bend Clutch 94-98 7.3L Power Stroke - Stock Power

Get rid of the dual mass flywheel, you likely will not notice a bit a difference, its a poor design.

Replacing the clutch is pretty straight forward and can easily be done in a day with basic hand tools and on your back with an atv lift or floor jacks.

Disconnect drive shafts
disconnect shift linkage for 4wd
remove stick shift from top side
drop starter
drop slave off trans
Seperate t case and remove for ease of removing trans,
remove trans support/skid plate and support trans
unbolt trans and lower, this is where a nice 1/2" swivel drive, 4-5' extension and a second set of hands really helps
unbolt clutch
unbolt flywheel
press new pilot into flywhell if need be

reinstall, drain trans fluid and fill with 6 qts through top side before reinstalling stick shift.

The zf did not have a cooler, I have considered welding a return and inlet bung on the Pto cover and adding an inline electrical pump to a cooler, they make finned case coolers that add abit of capacity but cooling is minimal and a waste of money IMO.

 

if this is the first time it happened, you should be able to run it fore quite a while as is if you do not beat it. i got over 3 years out of mine with a bad flywheel running it hard and putting it away wet.

 

Yes this is the first time this has happened. Thanks nossliw for that overview on how to do this. I would imagine another pair of hands/help would be of advantage on this. tjc ...I certainly hope I can get that kind of extended life out of it! But at the same time I always try to be proactive ahead of this kind of mechanical failure.

 

^^^^^^ Yeah, now that Tom mentions it, the flywheel is a prime suspect. Just for background, they shipped these trucks with a "dual-mass" flywheel. Almost like a clutch in front of the clutch. Two halves held together by springs and little plastic bits and God (or Ford) knows what else. The bit of "give" between the two masses supposedly takes some of the truck-like harshness out of the driveline, and eliminates gear rollover noise. Only problem is, when those bits holding the two masses together fail, they can grenade through the tranny case. When those parts start to fail, the clutch itself may have many more miles on it, but the flywheel is a ticking time bomb. We had one dual-mass go VERY loose with barely 80,000 miles on the truck; caught it JUST in time.

Slide under the truck, remove the inspection cover plate, and grab the flywheel and see if you can rotate it. I forget the actual "threshold", but if there's appreciable movement, stick a fork in it, that flywheel's done.