Hard to get M/T in gear in cold ambient temperatures before truck warms up...

[Q451990]

Well, the title says it all for the most part. It's hard to get the shifter into gear when it's cold outside - at least for the first mile or so of driving. It helps some if I let the truck sit and warm up to normal operating temperature, but it's still a little iffy until I drive it for a mile or two.

I checked and the fluid in the clutch master cylinder is in the middle range between min and max, but it's really dark - I know it needs to be flushed.

Does this sound like a clutch master/slave cylinder issue - or more of a problem with the clutch or transmission itself? I know that the clutch was replaced prior to my ownership - but I don't know if OEM parts were used - or anything about the quality of the installation. I recently drained and refilled the transmission with the recommended 80W-90, and that did not make a difference... same problem before and after.

The only other transmission related issue that I have noticed is that when I'm shifting and press the clutch, I can hear a little bit of a growl when I first press the clutch. That noise also only shows up in cold ambient temperatures.

Any suggestions?

Thanks!

Heath

[RT]

switch to synthetic transmission oil. My manual was same with regular gear oil the synthetic helps a lot. it is slicker and allows easy shifts when cold. Once warm regular gear oil thins out and shifts smoother. This is normal as regular gear oil is like molasses when cold, synthetic does not do that. Also helps with heat and slickens shifts.

[Q451990]

I thought of that, but I didn't think that dino gear oil thickened that much in our relatively mild temperatures - but if you say it helped in Montgomery, AL - then I think I'll give that a try.

When I say "cold" ambient temperatures, I'm talking about below 50F when I see it show up... probably in the mid to low 40s.

Thanks!

Heath

[YEPEE]

pull a quart out and add a quart of 30w, cheapest solution

[Big-Bird]

Is this in your Q45? There could be some other issues going on in that transmission of yours.

80W90 in most older manual transmissions doesn't cause the issue you are describing in cold temps. (Newer standard trannys use regular automatic transmission fluid.)

I had a 1986 720 4x4 with 5 speed and it went through -30 degree winters with no issues in shifting until the syncros started to wear out and the preload nut on the main shaft backed off.

Drain the fluid and check it for brass/steel filings. A small amount is normal but if you have large flakes you could have syncro or bearing issues that are just starting to show.

The other item that should be checked) You could also have a bunch of gummy residue at the shifter arm that is making the shifting tight/sticky.

[Q451990]

No... not on the Q. I'm thinking 80-W90 in the Q's transmission would be a major problem

I didn't notice any metallic filings in the gear oil when I changed it a couple of months ago. I had the shifter out of the case at the same time to replace a leaking boot and gasket... I also replaced the lower nylon socket since the parts guy sent it to me, but I don't think it was necessary. I didn't notice any crud anywhere.

No change in the performance after the drain and fill. Do you think there's a chance that the master/slave cylinder for the clutch is getting weak? I don't see any leaks.

Heath

[Big-Bird]

Your issue is not clutch related unless you hear gears grinding when you shift. Yuu stated it was hard getting the thing into gear until it warmed up.

You should check that nylon socket and see if something isn't binding. You may want to lube the socket with lithium grease when you reassemble it.

If your gears are grinding, even a little bit then you will need to check the master and slave cylinders for the cluth assembly. How many miles are on that unit anyway? When was the clutch last changed? You should also pull the inspection cover from the clutch shift fork boot and see if you can spot the clutch. Is the clutch getting thin? Check your fluid levels in the cylinders. If the level in the clutch master cylinder was really low and you only topped it up chances are the clutch may need changing.

[Q451990]

I don't have any service history prior to my purchase in 2003 (or was it '02?) other than what I can see. It was a Terminix fleet truck, and appeared to be fairly well maintained especially in the oil change department, but I don't have anything in writing. The clutch was definitely replaced at some point, but I don't know if they used OEM parts or something else...

No grinding at all - maybe it would if I forced it. Typically I'll just gently try several times and eventually it'll go in. I think I'll try flushing the clutch cylinders with fresh fluid... it looks very dark, but the level is fine.

Heath

[Q451990]

Well, I flushed the fluid in the clutch hydraulics today... wow, that was some filthy fluid! The master cylinder has a layer of black slime inside the reservoir. I doubt it has ever been flushed before. I flushed and flushed, but it's still pretty nasty. I don't know if I should risk contaminating it by wiping the reservoir out with a paper towel - or maybe just wait for it to fail and replace everything. I don't suppose I could clean the resivoir out with brake parts cleaner and flush it out that way?

I only bled it through the operating cylinder, not at the damper... seems to drive fine...

No clue if this has anything to do with my cold-weather problems... it's supposed to be cooler this week so maybe I'll be able to test it then.

Heath

[YEPEE]

you have 80/90w in your trans.. cold = thick oil, after you drive it awhile the turning gears warm up the oil (thins it up) and the shifting gets easier. try thinning the oil buy replacing a quart with 30w

[Q451990]

I understand viscosity, but I'm not sure that I want to go that direction... My thought is that the transmission was designed for 80W-90, and people are running them in much colder climates than SC with the specified oil... so I hesitate to change oils to a lighter weight... especially given how much it will thin out in the summer when we're looking at basically 100F for a month or two. I might go with a full synthetic though...

I might also try a rebuild kit for the master and slave cylinders, and a new flex line. Then I could rule out the hydraulics completely. Since my flush the other day I think the clutch pedal is sitting higher than before... not sure though. I'm not sure why a flush would do that... so it's probably something I just didn't notice before.

Heath

[mike_belben]

mine is exactly the same. i dont worry much about it, drives fine.

[Q451990]

mine is exactly the same. i dont worry much about it, drives fine.

Same as in hard to get into gear when cold, or high pedal height?

Heath

[YEPEE]

good luck! let us know what happens

[Big-Bird]

Well, I flushed the fluid in the clutch hydraulics today... wow, that was some filthy fluid! The master cylinder has a layer of black slime inside the reservoir. I doubt it has ever been flushed before. I flushed and flushed, but it's still pretty nasty. I don't know if I should risk contaminating it by wiping the reservoir out with a paper towel - or maybe just wait for it to fail and replace everything. I don't suppose I could clean the resivoir out with brake parts cleaner and flush it out that way?

I only bled it through the operating cylinder, not at the damper... seems to drive fine...

No clue if this has anything to do with my cold-weather problems... it's supposed to be cooler this week so maybe I'll be able to test it then.

Heath

Well lets give you some more help shall we. First of all why didn't you bleed the both cylinders? Brake cleaner is more for cleaning oil, grease and brake/clutch dust from external surfaces. The rubber seals in your clutch system don't respond well to prolonged exposure to brake cleaner and will usually swell and deform making them completely useless!

Rebuild kits are a great idea but you need to check for excessive scoring and pitting on the pistons and cylinder walls.

Brake fluid, used in hydraulic clutch systems, is water soluable so plain hot water can be used to clean the internals of things like master cylinders, slaves, calipers and pistons. (That means water is used only when doing a rebuild) You must have a good source of dry compressed air to dry everything before you re-assemble it.

TIP: If you are going to attempt a rebuild read up on a technique known as Bench Bleeding. It will save you plenty of greif.

Oh and if you want to wipe that gunk outa the reservoir instead of doing a rebuild, I would try using something like a mini spatula or clean toothbrush to remove most of the gunk. With the worst of it out, a quick paper towel wipe will get the rest. Them you can use clean brake fluid to flush the entire system.

[Q451990]

Well lets give you some more help shall we. First of all why didn't you bleed the both cylinders?

Well, I thought that since I was just doing a fluid exchange, and the fluid has to pass through the damper, I was OK just flushing from the farthest point downsteam... especially since I never let the master cylinder get completely empty.

Brake cleaner is more for cleaning oil, grease and brake/clutch dust from external surfaces. The rubber seals in your clutch system don't respond well to prolonged exposure to brake cleaner and will usually swell and deform making them completely useless!

Rebuild kits are a great idea but you need to check for excessive scoring and pitting on the pistons and cylinder walls.

Brake fluid, used in hydraulic clutch systems, is water soluable so plain hot water can be used to clean the internals of things like master cylinders, slaves, calipers and pistons. (That means water is used only when doing a rebuild) You must have a good source of dry compressed air to dry everything before you re-assemble it.

TIP: If you are going to attempt a rebuild read up on a technique known as Bench Bleeding. It will save you plenty of greif.

Oh and if you want to wipe that gunk outa the reservoir instead of doing a rebuild, I would try using something like a mini spatula or clean toothbrush to remove most of the gunk. With the worst of it out, a quick paper towel wipe will get the rest. Them you can use clean brake fluid to flush the entire system.

Interesting thought on cleaning with hot water. I think I'll just order the rebuild kits and flex hose at some point and rebuild... then I can really clean everything. I realized later that I have a mity vac available, so that should make the bench bleeding and future flushes easier than having the wife trying to remember "which one is the clutch?" and me yelling "the one that you don't have in your car!" over and over again

Thanks!

Heath

[mike_belben]

Same as in hard to get into gear when cold, or high pedal height?

Heath

i meant tough shifting when cold for the first few miles. the colder it is, the harder it shifts, even if the engine is off.

im gonna say your problem doesnt particularly sound pedal related. i mean all you need to shift is enough pedal stroke to get the pressure plate to release the friction disc for a moment, and that doesnt take much.. maybe an inch of stroke will shift most cars.

i rebuild honda and acura transmissions and quite a few times, have seen a syncro ring frozen pretty damn hard to the taper on the side of the gear, used ones as well as fresh out of the bag new ones. if they get pushed on hard, they will actually require a chisel at the seams to lift and free the synco.

my thinking about the hard shift is simply that the two metals are high in friction toward each other (the whole point of a syncronizer is to have max friction between the two parts in order to match speeds during the split second of time when shifting) and that after a day of sitting the oil has largely drained out. once the oil thins and gets in there, this issue goes away.

the frontier trannies are quite clunky in shifts compared to honda/acura as well as toyota W and R series. i always guessed it was syncro material selection and havent let it bother me. its been consistent without worsening.

[Nitewulf]

The more I read the more I was leaning to the syncronizers as well. It made me thing of those and the thrust bearing in the flywheel when he mentioned the grumble from it. I would think with wear and tear in your truck the afore mentioned syncros are starting to show their age a little.

[BOOSTFOOL]

had similar problem switch to thinner fluid and now its good