5 spd shifts much easier dead cold?

[Silverado]

The high mileage truck in my sig line has the 5 speed tranny. I've done all the usual driveway tests on the clutch, and everything seems fine. I've never really noticed anything untoward about the clutch at all.

What I find odd is that when I drive away dead cold (it is winter here in Northern Canada LOL) the truck shifts from 1st to 2nd to 3rd much smoother than when it's hot. By smoother I mean with much less resistance at the lever. There's never any grinding regardless. No gear or syncro whine ever either.

Any ideas?

Also, the manual calls for Mercon ATF in the manual trans. Why that vs. a regular gear oil like GL5?

 

[metalmacguyver]

gear oil is to thick to properly lubricate some parts of the transmission because the tolerances are held so tight. also it makes it much harder for the syncros to do their thing. it would be very difficult to shift.

 

[Silverado]

That's an interesting comment metalmac... it's just that this is the first manual tranny I've had that called for ATF as the lube for it.

 

[brendank]

It's not very typical for a tranny to shift smoother cold than warm, especially at very cold temperatures. Either way, I don't think it's anything to worry about, especially if it's not grinding or otherwise complaining.

As was already said, gear oil is much thicker than ATF, and won't properly lubricate an M5R1. Most modern standard transmissions use ATF.

 

[racsan]

that is odd, i let mine run for 5-10 min before i leave in winter just to stir the oil up a bit in the gearbox. regular gear oil would destroy the "yellow" metals used in the syncros. transfer cases also spec atf in alot of cases
________
History of Ford Motor Company specifications

 

[Silverado]

Interesting info friends, thanks.

I too let mine run in neutral for a minute or 2 before I leave.

I suppose a fluid change won't hurt it... I'll get after that one of these days soon.

 

[MAKG]

Lubricant viscosity is certainly a variable, but I doubt it's why ATF is used. M5ODs use a paper-impregnated blocking ring. Gear oil will not do nice things to that.

ATF in manual transmissions is not nearly as rare as it used to be.

Given that there is an issue with multiple gears, I'd suspect a clutch problem. Particularly, the pilot bearing. That can behave much differently on a warm engine because the various parts aren't all the same temperature.

 

[Silverado]

Thanks for the input MAKG. I plan to haul the engine and tranny out on the Easter or May long weekend and do the clutch, timing set, pan gasket, headers, probably the rear main seal and whatever else while I'm at it. It's not really a problem at all; I'm sure it'll get me till then easily.

 

[Totalled]

Air in the hydraulic system. Cold = less air. Warmed up = expanded air, more to compress, less clutch release, harder to shift. Pilot bearing is also plausible.

 

[Danger-Ranger96]

i would say a fluid change might help, my 96 used to do it sometimes, after i changed the oil everything seemed alright again.

 

[Robin Hood]

i would say a fluid change might help, my 96 used to do it sometimes, after i changed the oil everything seemed alright again.

took the words right outta my mouth. except i dont have a 96.

but yeah. fluid change.

 

[F150hybred]

Silverado... I may get bounced terribly for this, but here in Winnipeg, our winters get cold too. I'm not gonna split hairs about who gets colder than who... that's a different thread for a different time. My point is, the "weight" of most major brands of ATF is about an AW20. What we have been doing here, with excellent results is using a FULL synthetic 0W30 engine oil. As I'm sure ewe all know quite well, ATF is high in detergents... nothing wrong with that... in an AT. The 0W30 engine oil, believe it or not, is about the same weight as ATF. Using this oil in your trans will not have any "detrimental" effects on longevity. If anything, it will improve the life of your trans.
In the hotter states, they frequently change out the ATF for 5W30 synthetic oil just for the simple fact that the ATF can't withstand the high heat temperatures. Many people have tried it and some were quite amazed.
Now, it's up to you if you want to try this, but if you don't, no problem. I'm sure you would be fine using the factory specified ATF. It's lasted this long, rite?
For those of you that don't believe me.... below is a thread from another site. Might be worth the read.


http://www.dezertrangers.com/vb/showthread.php?t=59450


From here, you can form your own opinions.

 

[MAKG]

Crankcase oil is also high in detergents. And anti-scuff additives and colloids and high-temperature additives and a bunch of other additives designed for the environment of a crankcase. The viscosity is about the same, but if you think that's the only variable, you're fooling yourself. The transmission was designed for ATF. NOT CRANKCASE OIL. If you want to ruin your transmission, that's your business, but do NOT give that advice to others unless you have some actual systematic and controlled tests to back it up. "It worked for me" is the argument for using leeches to cure Syphilis, so don't even go there.

 

[F150hybred]

Makg... did you see the part were I said.... "Now, it's up to you if you want to try this, but if you don't, no problem. I'm sure you would be fine using the factory specified ATF. It's lasted this long, rite?" .... I'm assuming not. I'm guessing it's my fault for "thinking outside the box".