Iv got a mazda 5 speed behind my 4.9l and i think it might be overheating.

I do alot of idling, and i think that may be causing it to overheat. I know that when idling in neutral the gears arnt moving but the shafts and syncros are. But they dont move enough fluid to keep the bearings cool. I have 3 quarts of ATF and 1 quart of 15w-40. But it does it with 4 quarts of ATF as well.

After it idles for a while and i start driving agian, it is extremly hard and somtimes impossible to shift into second, and hard to shift to fourth.

Has anyone else had any simular experiances? Its really annoying. I read on a local gear shops web site that you can have a simular problem with the ZF 5 if you idle, but it seems so unlikly.

Any ideas are appreciated.
Thanks

 

I really doubt you are overheating your transmission. If so, you would be the first person I've ever heard of with this problem. A good way to check is with an infrared temp gun, which you can get for less than $100 these days and they are a good diagnostic tool to have on hand.

How many miles on your truck?

 

I would think that the vast majority of heat in a manual transmission comes from sliding friction between the gear teeth, which increases with the force or load on the gears. There really shouldn't be enough load on the gears or bearings in neutral to create excessive heat. But, as Andy said, the only way to confirm or reject the possibility is to measure the temperature.

 

ya, my theory behind the over heating is that you leave the bearings in the syncros turning in a small pool of ATF fluid that isnt circulating, and they sit there for 30 plus minutes. And because this only happens after i sit for a while, i figured that it might be an issue.

andym- i have an infered temp gun and i will check the temp, what kind of temps should be normal? I remember a few weeks ago, after having this issue all day, i checked out the tranny by hand, and it was incredibly hot.

Any ideas where my issue may be, if its not over heating. What could cause the tranny to be hard to shift after idling?

Thanks for the info, I plan on a tranny swap to the ZF5 soon, but i would like to get it figured out.

 

Not sure what the normal temp should be, but try this. Drive around for a half hour or so and get everything good and hot. Take temp readings with the gun. Then let it idle for however long you normally would and take the temp readings again.

Why are you letting it idle for 30 mins at a time?

Again - how many miles are on the truck?

I would go back to using what the factory calls for - ATF and no motor oil. The hard shifting could be caused by worn out synchros (which is why I keep asking you about the mileage) which could be because you're using the wrong fluid. There isn't any reason at all to use anything different than what Ford says to use. I doubt you have done the amount of research into transmissions that their engineers have.

It could also be the firewall flex issue. When you shift into reverse from a complete stop is there any grinding?

 

Ill get the temp readings tomorrow.

The reason it idles so long is i often haul equipment on trailers and it sits and idles while i load and unload, or work on equipment(im primary a mechanic) And its nice to hop into a A/C cab after being out in 105 degree heat.

The truck has 125000 miles, 85000 were easy, then i got the truck and i tow and haul alot. I had the top of the tranny off and the syncros looked great for the mileage. And the fluid doesnt matter, it just changes the feel of the tranny, how stiff it is and how it shifts. The differences in ATF and motor oil are very minimal besides the friction and detergent additives.

The transmission shifts fine all day long as long as it doesnt sit and idle. Its really kinda strang.

Thanks for the help, and please keep it coming.

 

with synomesh trannys the fluid DOES matter, it matters alot actually, improper fluid can kill snycros, try changing the oil to 100% something either recommended by FORD or something rated for syncros, i use LUCAS oil, expensive but damn good stuff, i use 100% lucas in diffs and trannys and it will shift great all day, mine does idle but not that much, but i do see high operating temps and i have never had this problem

well i lied i had the problem before but it was just hard to shift at any temp, it was shift forks and deteriorated shift ball seats

a tranny at operating temp is actually quite hot, and to fel it with your hand you would think it was too hot but in reality chances are it is fine, like andym said, after driving for a bit to get it to normal operating temps, check the temp then let it idle for half hour and compare

there are alot of things in a tranny that can make hard or impossible shifts, before i replaced my shift forks it would shift fine most of the time then one in a while you would be in 4th, and it would not come out of 4th, that happened twice before i got the forks and replaced them and hasnt happened since

i too am a mechanic and i agree with the working outside when its hot, especially being a big rig mech i get to work outside in 100+ degrees F and on top of that work on an engine that sees 210 degrees F before the fan kick in and yes it get hot and it can suck after a while, but i would not think about jumping into an A/C cooled cab after that, id have the truck shut off then when i leave id roll down the windows to slowly cool down rather then throwing myself into shock

 

Exhaust system running too close to trans or leaking on to trans.?

 

if my memory serves me correctly 300 inline 6 exhaust is not very hot, it would have to be pretty hot and pretty severe to cause problems with a tranny, my inline 6 exhaust is just fine where it is so unless his is modified it should also be a good distance away from the tranny, and the exhaust on an I6 is also only on 1 side of the tranny so it would take even more exhaust temp to heat up the tranny that way


get any temp records yet? this is interesting

 

Thanks for all the info, I have yet to get temp readings, im working on finding my temp gun??? Ill try and get them tomorrow. Sorry for all the delays, work has been really tough.

The exhaust is stock and in great condition. And i recently replace both the shift forks because they had worn through.

And when i shift, its not like its grinding or not trying to shift. Its as if you haven't even pushed the clutch in. It feels like you sitting still with the engine running and try to pull it into 2nd with out pushing the clutch. It feels impossible. It really is strange.


Ya, the A/C hardly takes the edge off the heat. If its gonna be sitting for awhile while im working ill shut it off, but most of the time im out on site, is because its an emergency and i have to have strobes and lights and its easier to let it run for 20-30 minutes. any longer then that and i shut it down. And i agree, it is no fun to crawl into a 200 degree engine compartment haha.

Thanks for the info, i really wanna figure this out. even though im looking for a new tranny. id hate to destroy this one.

 

why not? chances are you will not get core charge back for the mazda if you buy a zf? i cant anyway i tried...im gonna look into getting an eaton fuller tranny (they make every single big rig tranny i have ever seen HAHA) they cost about as much new as a zf does rebuilt (well for me cause i get them at cost plus 10%)

if you say its kinda like trying to shift without pushing the clutch maybe thats your problem? malfunctioning clave cyliner of clutch maybe?

 

also check stupid plastic bushing that fails at about your mileage in the clutch linkage.. had same issues.. replaced bushing then the pushrod on the clutch master cly broke from being out of whack for however long while pulling into NAPA, <3rd owner> that was scary lucky i wasnt in a higher gear at a higher speed i may have panicked was thinking i needed to put a new clutch and slave in but now shifts easy.. randomly I did have a metallic swishing sound in second and a bit of trouble going into same gears recently which lasted about a month, i did nothing and she's now shifting smooth. time for a drain and fill i think.

 

I got the Temp readings today. I only had one chance to take them and right after i got off a 30 minute drive on the highway the bottom of the tranny was at 138, the top 148, After idling another 20 minutes it climbed to 148 on the bottom and 158 on the top. not terribly high. But this was on the way to work in the morning. I believe it might get warmer later in the day. But not so much so that it would cause issues.

9.ford.5- i have a guy who will take the mazda as a core for the ZF, so i at least need it in decent shape. But the most urgent thing is that i dont have the time to do the swap and i need the truck functioning at 100%.

I have dealt with the clutch bushing issue before. 10 bucks for that little bushing from Ford. I fixed it by drilling a hole and putting a cotter pin and washer to hold the new bushing on.

Also, the whole clutch system has been recently replaced and is a great condition. If it were a issue with slave or master it would occur more often and in more gears, and Iv dealt with more clutch on this particular truck alot.

ill try putting in pure atf if i have time, and well see if that cleans it up.

Thanks for all the help and any suggestions are appreciated!

 

if its hard to just shift into gears it could be synchros