ATF in a Manual Transmission?

[CheeseHelmet]

I was looking around on a local Mazda forum and some people were suggesting that using ATF results with smoother shifting than gear oil.

What do you guys think?

 

[bafilio1]

I think that, thats a load.. But just my opinion... I don't see how ATF being thinner would smoothen shifting. My shifting is pretty buttery idk bout you

 

[CheeseHelmet]

Buttery, eh?

I've always had a problem with second gear. For instance, at a stoplight I'll take off and midway through the intersection I have to stop accelerating because I'm waiting for the 2nd gear synchro to do its job. I know it's a mechanical issue but if I can find something that makes it a little smoother I'd be happy.

So what are you using to achieve your buttery-ness? I'm using some expensive castrol synthetic crap at the moment and it doesn't seem to be any different from whatever came with the car. I've heard GM synchromesh, redline and royal purple are good but they're also pricey (5L of ATF is only $15).

 

[bafilio1]

I'm pricey. I use royal purpple. But I just changed gear oil a few months ago. It wasn't too bad at Jegs. But yeah ATF is cheaper but its changed or added more frequently vs. gear oil.

Just a friendly FYI with my old 4g64 I would have the same problem with 2nd and first. Turned out to be a bad slave cylinder and master cylinder.

 

[Dimitrios]

Go to your GM Dealer, and ask for AC Delco Part 10-4014 (GM #88900399). It's the Synchromesh Manual Transmission Fluid + FM (Friction Modified).

And along with considering changing your master/slave cylinders, try to adjust your clutch pedal. It needs a tweaking after a while as other associated clutch parts wear.

 

[CheeseHelmet]

Just a friendly FYI with my old 4g64 I would have the same problem with 2nd and first. Turned out to be a bad slave cylinder and master cylinder.

This is intriguing, I would have never though of that but it would make sense! I'll have to read up on how to inspect that system and I'll be sure to let you know if I'm successful.

Go to your GM Dealer, and ask for AC Delco Part 10-4014 (GM #88900399). It's the Synchromesh Manual Transmission Fluid + FM (Friction Modified).

Please excuse my ignorance, but what does "Friction Modified" mean?

 

[bafilio1]

This is intriguing, I would have never though of that but it would make sense! I'll have to read up on how to inspect that system and I'll be sure to let you know if I'm successful.

I've never looked at my slave cylinder or master cylinder on the p5... but on the eclipes I Honestly I had no idea the master cylinder was bad... I just guessed and changed it, improved but didn't totally fix it. THEN, i looked at the slave cylinder and the piston and o-ring were slightly damaged. So I just got a rebuild kit. replaced the internals slapped it back on there with the 2 bolts and reconnected the line and BAM I was able to shift again with no problems. but keep in mind this may not be the same issue.. But sounds VERY similar.

**Edit I also had no idea that this was the problem. I just noticed that I had a VERY hard time shifting to first and worse time going to 2nd while rolling. I would have to do the same and fully stop. Slam it into 2nd then SLAM it into first to take off.

 

[Matt V]

Go to your GM Dealer, and ask for AC Delco Part 10-4014 (GM #88900399). It's the Synchromesh Manual Transmission Fluid + FM (Friction Modified).

And along with considering changing your master/slave cylinders, try to adjust your clutch pedal. It needs a tweaking after a while as other associated clutch parts wear.

No need to go to a GM Dealer, go to your local Autozone. It's cheaper and more readily available.

 

[justanothermp5]

+1 syncromesh was at autozone when i picked up my mobil 1 trans fluid
i used mobil 1 for no particular reason, i just trust the brand

works good for me and worked good for my brother, he said it smoothed his shifting out alot

 

[Matt V]

+2 on the Mobil 1, changed to it not too long ago.

 

[Dimitrios]

No need to go to a GM Dealer, go to your local Autozone. It's cheaper and more readily available.

Well, I've *never* been able to find it at any parts store. From what I gathered, the stores only have the Penzoil Synchromesh flavor (less the FM component).

I know some people have been able to find it, but in the 5-10 stores that I casually check to see if it's sitting on the shelf when I drop in, it's never there (plenty of Royal Purple though).

 

[sephiroth]

ATF fluid is around a 15w oil as opposed to the reccomended 75w-90w. So it will likely give smoother shifts at the price of reduced gear life.

 

[Stickman]

As to the suggestion to adjust the clutch pedal.
Anybody know how to on a P5?

 

[CheeseHelmet]

ATF fluid is around a 15w oil as opposed to the reccomended 75w-90w. So it will likely give smoother shifts at the price of reduced gear life.

Are you talking in terms of gear oil or motor oil for ATF? I say this because they each have their own viscosity index so you can't easily compare them like that.

API viscosity ratings for gear oils are not directly comparable with those for motor oil, and they are thinner than the figures suggest. For example, many modern gearboxes use a 75W90 gear oil, which is actually of equivalent viscosity to a 10W40 motor oil.

From: http://en.wikipedia.org/wiki/Gear_oil

 

[CheeseHelmet]

As to the suggestion to adjust the clutch pedal.
Anybody know how to on a P5?

What do you mean by adjust?

I took a look at the pedal this morning and set it to disengage the clutch earlier in the stroke but it didn't do much (you can't make very big adjustments).

Have a look at page 05-10-4 of the service manual for more info.

 

[CheeseHelmet]

I've never looked at my slave cylinder or master cylinder on the p5... but on the eclipes I Honestly I had no idea the master cylinder was bad... I just guessed and changed it, improved but didn't totally fix it. THEN, i looked at the slave cylinder and the piston and o-ring were slightly damaged. So I just got a rebuild kit. replaced the internals slapped it back on there with the 2 bolts and reconnected the line and BAM I was able to shift again with no problems. but keep in mind this may not be the same issue.. But sounds VERY similar.

**Edit I also had no idea that this was the problem. I just noticed that I had a VERY hard time shifting to first and worse time going to 2nd while rolling. I would have to do the same and fully stop. Slam it into 2nd then SLAM it into first to take off.

As I said in a earlier post, I checked out the clutch pedal but couldn't really make much of an adjustment...

I looked at the clutch master cylinder and the release cylinder as well. The master cylinder is really rusty and the release cylinder is clean. I couldn't see any leaks though so I'm kinda lost.

Is there any way to test these parts or must I replace them and hope that they were the problem?

 

[bafilio1]

I just replaced them and prayed it fixed it which it did. The slave cylinder rebuild kit is under 20$ and could be worth it if your a high mileage p5. The master cylinder for my 4g64 was about 40$

 

[CheeseHelmet]

I just replaced them and prayed it fixed it which it did. The slave cylinder rebuild kit is under 20$ and could be worth it if your a high mileage p5. The master cylinder for my 4g64 was about 40$

By slave cylinder do you mean the clutch master cylinder or the release cylinder (the one bolted to the transmission)?

 

[CheeseHelmet]

I did it. My transmission is now full of foul-smelling ATF.

Did it make a difference? Kinda... It feels smoother going from first to second but sometimes it's still notchy.

I kept all the old gear lube just in case, but I think I'll be sticking with it.

 

[bafilio1]

sorry on the 4g64 its called the "slave cylinder" its the one bolted to the tranny. That one was most of my probelms. I couldn't tell that it was leaking either until I removed the rubber boot and clutch/brake what ever yo uwant to call it ran out.