pending noone does it before i get home from the D ill post it. Bc im damn sure gonna change the "goup" thats in my trans:o

 

The GM synchromesh and the Pennzoil synchromesh is the same thing, the only difference is price.

 

About three weeks ago I put in Pennzoil Syncromesh.

For the last two mornings the first shift to second gear has resulted in audible grinding. After that it is gone, but it doesn't shift any smoother than before with the syncromesh in it.

It has gotten a lot cooler here and that likely has something to do with it. Morning garage temps have dropped into the mid 50's since it is close to freezing outside, which is probably most of the issue. As I said, after the first shift it is fine, and after the car warms up it does shift a lot easier than when it is cold.

I'm not happy at all. Never had this issue with the factory fill.

Car has only 24k miles on it.

 

Hmmm...I've read this entire thread and was convinced I should try the Pennzoil until the last comment about cool temps and grinding. I'm using RP now after I developed an annoying grind in 3rd and 4th. (Looked like DexIII was in it). I know my synchros are probably to blame but the "too little friction with synthetics" makes sense. So do I try the Pennzoil with cool temps coming?

I'm sooo confused!

BTW, the trans still grinds with the RP.

 

Tony, I tried the GM Syncromesh two years ago in my 2000; and it just seemed harder to shift, like it was too thick. No grinding, but just more resistance on all movements of the shifter.
I drained it, and put in the old-style Pennzoil Dex III that I found at Pep Boys for $3 per qt.
With the Pennzoil I immediately noticed much easier, smoother shifting -particularly when the car was cool.

However, after 2 years and maybe 5k easy miles, I notice a bit more difficulty shifting to 1st or 2nd, and I hear a slight whine in 5th gear when cruising at 50 MPH or so (gotta stop that!).

So, I'm kinda at a loss. I think I should try something else, but if the Penn SM is the same as the GM, then no reason to try it, it's probably gonna be too stiff.
Amsoil has reportedly changed their formula on the ATF, and now recommend the ATD for our trannys. I thought I'd try Amsoil, but now not exactly sure which one to buy.

One comment though: clean and lube the shifter. That made a bigger difference than the fluid changes.

DG

 

why not just use the recommended oem fluid?

 

bc syncromesh is a few bucks cheaper and its the same thing...according to some fellas that have posted

 

Synchromesh (GM/Pennzoil) have different part numbers than those of the fluid recommended by GM for the c5 manual transmissions. The recommended fluid is #88861800, which is the successor to Dexron III, versus #12345349 for SM. I understand that people are happy with the shifting feel from SM, but this doesn't mean it's providing the proper protection.

This is a similar issue when people choose a gear oil. Dexron LS is what GM specifies as it has a very specific amount of friction modifers for the corvette differentials. None of the alternatives can really match this (even Mobil 1 admits this on their website).

 

im just telling you. if you havent read through all the pages then maye you should. Its been posted more than once.

 

About 20,000 miles ago I put in Amsoil ATD which made a big difference in feel and also minimized the heart stopping pop out of 1st. The old fluid was very clean when it came out, (PO may have changed not long before I did) so it does not seem that fluid degradation contibuted to the poor shift feel.

If you go to Amsoil, it is important to use the ATD as it is formulated to work with the paper rings of the earlier cars (pre 2002 I believe).

20,000 miles later shifting still feels beautiful and I have not noticed any of the issues mentioned in conjuction with using synthetic.

When I installed the Amsoil I had the stock shifter. Later I installed the C6 shifter which made a tremendous difference and virtually eliminated the operator error pop out of 1st.

 

Every single manual transmission I've driven since the 60s had to be double clutched from 1st to 2nd the first time in cold weather. This includes British sports cars, CJ5 Jeeps, Z28 Camaros, Pintos, fuel-injected-turbo-charged French hatchbacks, Dodge vans, Fiat sports sedans and now the C5 Corvette.
I run Amsoil ATD in the C5 and it shifts great but I still hit the pedal twice first thing in the morning.

 

Seems I have the opposite issue with my old-style Pennzoil Dex III, now that it is getting a bit cooler here in Dallas.
On the first shift it is butter-smooth, and stays that way until the tranny warms up a bit. Then, it seems like the bushings or something expand a bit, and the shifting gets a bit stiffer.
I guess, given the choice, I would prefer the opposite: sticky when cool, but smooth when warm.

Of course, I also wish that extra 30 lb-ft of torque would hang around after the engine warms up.

Guess I'm just doomed to take really short, fast trips - Ha.

DG

 

Well, to follow-up on this thread;
Heeps is absolutely right; when GM discontinued the DEX III, they then brought out the new recommended lubricant #88861800 Manual transmission and transfer case lubricant.
This is different stuff from the Syncromesh manual trans lube.
I searched around and found a couple of Chevy, Hummer, and Caddy TSB's that recommended the 88861800 as a replacement for the DEX III in trannys and transfer cases that had previously used DEX III.

So, GM's not making us live with the thicker Syncromesh or the DEX VI.

Yesterday, I bought 4 quarts of the -800 lube and popped it in the tranny. Looks like DEX III, smells like DEX III, pours like DEX III, shifts like DEX III.
I'll bet it is DEX III, but only "The Shadow" knows for sure.

A quick drive is all I have done, so I'll wait to report on shifting performance both cold and warm; but so far so good.

Ah, the disclaimer: I'm not implying that this lube is better or worse than the Boutique lubes, or the GM Syncromesh. I'm just saying this is the GM-recommended replacement for DEX III, the Syncromesh is not.

Now, that sucker better shift pretty good, or I'm sure gonna feel pretty silly.

DG

 

DG:

Love to hear your impressions in person. I'm thinking of changing my tranny/trans fluid.
We have a weekly GTG in Garland every Sunday evening at 6pm

http://forums.corvetteforum.com/sout...areas-iii.html

Hope to meet you one evening !
Toque

 

hmmm glad i waited....i almost pulled the trigger on the Pennzoil SM...now im curious. Report back please

 

Yeah, me too! I retired a couple of years ago, and now work part time, delivering parts for Advance Auto Parts. We recently started stocking the Pennzoil SM, and I was going to buy some and do a switch. But maybe I'll wait.

My other concern was fluid compatibility. As I mentioned earlier, I've had the RedLine fliud in my car for 9 years, and as it's been discussed in other threads here, you don't get a 100% fluid drain from the transmission. Therefore, if I/we switch fluids, and the two aren't really compatible, you could wind up with a real mess in the tranny....

 

Toque, I'll come to the GTG. I assume 6:00 PM Sunday at the Red Robin near Target?
Like your Z, but you need to do a few mods - Ha.

Well, we're getting 50% of our annual rainfall in Texas today (seems like) so I can't do any further testing of the new GM tranny fluid for awhile. Shifts real good sitting in the garage though!

DG

 

DG:

Yes Red Robin near Target.

Yea heck of a rain at lunch ! I almost got soaked coming out of a restaurant at lunch !

If its nice we meet. If its wet we don't...
What mods do you think I need. I already know I need a blower, and Tirgershark kit, and ...and... and... the list goes on...

Toque

 

Here's the update from my earlier post on the GM DEX III replacement.

About 3 years ago, I tried the GM Syncromesh #12345349 in my 2000.
Way too stiff; hard to shift when cold, and still pretty syrupy when hot.
Just felt too thick everywhere.

Drained that and found old-style Pennzoil DEX III. Big difference, felt just like it did with the factory lube.
After a couple years, though, I began to notice it seemed a little stiff when it got hot. Great feel when cold, but just a tad sticky when hot.
I also have noticed a very slight whine in 5th geat at low speeds. Had it awhile, probably before the switch to Pennzoil, just not sure when it started. Very slight, could have been there for years.

When I saw the post above about the GM DEX III replacement #88861800, I decided to try it. It looked, smelled, poured just like DEX III. After a few weeks in the tranny, it shifts just like DEX III also.
The slight hot "stickiness" I felt with the Pennzoil DEX III is gone, this stuff feels the same whether cold or hot. No issues at all; not silky smooth, but then it's never been; it's a Vette. The very slight 5th gear whine is still there, but I didn't really expect to change that when basically going from DEX III to DEX III equivalent.

Conclusion: the 88861800 is the GM recommended lube for the C5.
It replaces thier previous DEX III, and very very likely is the exact same DEX III with another number - to avoid the trademark issues.

Whether it's better than some of the aftermarket products, can't say.
But I can say it works much better in my tranny than GM Syncromesh, and a little better hot than 2-year-old Pennzoil DEX III.

DG

 

Say Mate, could you tell me the quantity you put in 6-speed? Can't find it in mega manual.
Tks