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Pennzoil Synchromesh Manual Transmission Fluid

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DSMRevolution

20+ Year Contributor
1,630
10
Dec 6, 2002
Sioux Falls, South_Dakota
Well, the :notgood: is my opinion anyways.

I rebuilt my transmission about 8,000 miles ago and ever since I have been using Pennzoil Synchromesh. It is the same product that you can find at GM dealerships (part #12345349). The Synchromesh is safe to use in our transmissions (in other words, safe to use with our brass blocker rings) but it never felt quite right in my transmission. Don't get me wrong, it is a fantastic product but for me it felt like I was shifting the transmission without fluid in it at all (rough gear engagement, etc).

Within the 8,000 miles I have changed the Synchromesh fluid 4 times (a little excessive but wanted to make sure it was clean after the rebuild). Each time I drained it and it came out almost identical as it went in (a little dirty but this is a given). Anyways, I wanted to do a experiment. I decided not to change my transmission fluid for about 4,000 miles of city driving.

Yesterday I changed the fluid and it looked quite different then when it went in. It was somewhat milky and it glittered on the way to the drain pan. Not something that made me :) . Looking at my options I decided to change fluids to see if I would notice any difference in shifting or fluid draining (milky ness, metal particles or flakes etc). I purchased 3 quarts of Coastal (which is safe for our transmissions also) 75w-90 ($3 quart) and after pouring that in I went for a test drive.

Much better. Transmission shifted through all gears smoother then it ever has. Previously using the Synchromesh caused hard engagement into first and reverse gear. When any other gear would engage I would feel a small clunk in the driveline if I didn't rev match perfectly. Using the Coastal fluid made a huge difference in my manual transmission over the Pennzoil Synchromesh. The small clunk I felt is totally eliminated and all other gears engage smooth including first and reverse (reverse is still a little notchy but that is because it isn't synchromeshed).

*Incase your wondering, I believe that the small clunk I felt was one of the sliders engaging the hub over the blocker ring and gear.

Anyways I just thought I would share my experience. I am not by any means saying that the Synchromesh is a bad product, it just didn't work for me. I figured some of this information might be useful for somebody! :thumb:


More Information:
Coastal Gear Oil "trials"

Pennzoil Synchromesh Information
 
That very intresting.. I think the reason for that has to do with the friction modifiers that are in that fluid. It make the syncho grab harder.. Because I have the same issue with using BG. What I've wanted to do is add a bottle of redline 75w-90 and then use BG for the remainder and see what happens.
 
When rebuilding the transmission the only thing that was installed that would affect shift quality was double 2nd. I used Mitsubishi parts so it is the same found in 1994 year transmissions. Bearings, seals, gears and lots of OEM parts were replaced. When shimming the transmission everything was set toward the tighter side (have exact specs around here somewhere). I am happy using the Coastal gear oil so in about 4,000 miles I will drain it and do another update on how it looks coming out compaired to going in.
 
I personally don't like running straight syncromesh either. I just got about 1.5 quarts of mobil 75-90 gear lube from my work ( about $2-3 a quart ) and then mixed it with the rest syncromesh. This seems to be the best for my tranny and this is what I will do in the future.
 
Sweet cause I have to change mine this weekend. So what does the GL3-4-5 mean anyways? I just have a N/T 5 speed 96 Eclipse.
 
Regarding GM/Pennzoil Synchromesh

I tried it in a 90 GS-T I drove for a while before pulling the motor to fix my AWD. It had 95,000 miles and was grinding in 1st-3rd, I adjusted the clutch and it helped a little so I read on the forums to try the GM/Pennzoil Synchromesh and it was horrible. Just like DSMRevolution said like I had put ATF or something in as the grinding became far worse.

I knew that Mobil 1 Gear lube is pretty good but when I compared it to the AMSOIL Severe Gear my friend was using it was a but thinner (both were the same temprature). I use Mobil 1 for motor oil but the gear lube did not seem to be quite as heavy duty as the AMSOIL Severe Gear. AMSOIL Severe Gear is what I have been running in my AWD tranny and it now has 180,000 Miles on it and still shifts good as I can push it into 1st without grinding while moving (which seems to be a good test from the 5 or so DSM's I have been in).

P.S.

I had to also rebuild my center diff about 5,000 miles ago and upon installing new pole nuts and retorquing them, and they torqued down slightly furthur then the original ones. it did seem to restore some shifting performance. Although I am not sure if it actually tightened the syncros or was just a fluke that it shifts better.
 
With BG Synchroshift I can go back to first at 20 mph without a double-clutch.

Of course, my transmission took me off it's Christmas list a long time ago and I once overheard my synchros discussing coal, but I'm sure these are unrelated.

- Jtoby
 
I have to agree when you said the fluid came out milky. I've also been using Pennzoil Syncromesh and have changed it about 5 times since I've got my tranny which is a TRE rebuild. I didn't like the look of the fluid when it came out. Gave me a bad feeling about this fluid. Also when it came out the car was recently driven so it was hot. The fluid came out as thin as water if not thinner. I don't expect it to help protect much if that's the case. I guess if you live in a cold climate Syncromesh is nice. In areas with temps around 70-95 degrees something thicker would be better imo.
 
Alright since we're on the topic of tranny fluid all these numbers are confusing me. I have a 99 spyder gs with a 5 in it and replaced the clutch, plate, and flywheel about 6k ago. When i put new fluid in it I replaced it with 75w-90 synthetic. No here's where I curious and wonder what everyone else thinks. About 500miles after I finished I started getting a low vibration in 1st and 2nd when hard on the gas. It shifts fine up and down and no other gear does this. Now during the summer I never had a problem, but now that the temp is around 30 all day it seems to be reoccuring. Could this be the synthetis and if so can I go back to standard fliud? You guys ROCK:rocks:
 
Ive been using penzoil synchromesh recently as well. I had a tranny rebuild by TRE and the first time draining the fluid it came out thin as water as well. I recently found a vendor that stocks redline gear fluid so I'm going back to the real stuff.

But damn does that stuff get expensive. I always have to end up pulling the transmission out every couple of weeks because something breaks. I probably have thousands spent on Penzoil, LOL.
 
damn im experiencing knotchy shifting also and im using all penzoil. im going to try to supplement 1.5 of each and see how it does. when its summer time and its hot my transmission shifts perfect but when its cold with the syncromesh it shifts like garbage. does anybody have the same problem????

thanks
david
 
DUH! We all have the same problem! The bandaid is the Synchromesh fluids which shift easier when cold. But they don't protect as well IMHO, and you must change it frequently because it does not protect as well.

Simply put: Granny it till it warms up. That's what I do, not near as fun but oh well, the engine is still not warmend up either at that point, so you might as wll wait for everythihng to get up to temp before you rod on it.

It is an old car afterall.
 
i mean when its cold outside it shifts like crap all day. when its warm it shifts like a champ all day! i guess what im asking is what should i use during the cold months and what should i use when its hot outside?
 
Well once you drive it for a while in the winter, like after you have driven a few miles or so, it gets better, though, right?

Anyway, to answer the question: THinner in the winter, thicker in the summer.

So use one of the Synchromesh type of fluids in winter, and the thicker Redline MT 90 in the summer.

Frankly changing gear oil more then once a year is a pain in the rear, IMHO. But if you want to, be my guest.
 
I just recently starting using the penzoil stuff. I was very pleased with it over the BG synchromesh II.

Those are the only 2 gear oils I have used as of yet. So far the penzoil has worked better for me.
 
from researching this topic alot i came to the conclusion on alot of trans fluid secrets,and what alot of the people going fast prefer.

first off would be neo synthetic...some say the rhd kind some say just the heavy duty

some same a mix amsoil and neo synthetic (aka shep)

ams quoted 2 bottles bg syncroshift,1 bottle redline heavy shock proof

and in cars with syncro/high mileage lightweight shock proof mix

personally i dont like the pennzoil,i had it in there,and it dont like torque....Im running bg/redline mix for alittle then most likly going neo/redline mix

there also this mobil shc630 trans fluid you can get from grainger....lotus warrentees it in all there trannys,and they also certified this castrol fluid,but its only in europe,but word has it that they are some good fluid for our trans also

The thinner stuff will always shift better,but its not gonna take the shock as well when your beating the snot out of the trans.If the trans is right in the first place there shouldnt be problems,its always the guys with syncros going bad that complain and have opinions on tranny fluid,but in there cases lighter fluid is gonna make the "going bad" trans shift better.

But alot of people have opinions,your never gonna find the perfect combo,but those are the combos of people making some serious power,so take it or leave it
 
I have to agree with some of the other posters. When warm, this stuff is great. When cold, it just totally blows and its VERY hard to get the trans into gear at times.
 
I'll concur with all of the above.

I rebuilt my GST transmission and decided to fill it with the Pennzoil branded fluid. On cold days, the trans hates to be shifted until after about 10 minutes of driving. Even once warmed up however, there's a bit of a 'clunk' when upshifting. Not the type associated with failing synchros as gear speeds don't seem to be a factor.
 
Defiant said:
All true. 50K later, I'm still very satisfied with the Pennz.

i am with you on that one i have used it in my z-71 truck which now has 220,000 miles on the stock tranny and then i also use it on my turbo CRX b16 tranny and my dsm tranny. in the dsm tranny it made a big difference with bg it use to grind second gear all the time untill the tranny got warm then when i switched over to gm syn. it was like a new tranny works great just like it is a new tranny and the dsm has 208,000 on the stock tranny now.
 
I used BG Synchroshift II for about 30,000 miles. I drove hard during those miles with shifts up to 8,000rpm i ended up sheering 3 teeth clean off 2nd gear. I had my tranny rebuilt by a local member using shep parts and he told me Penzoil/Synchroshift was too thin and even though its great it doesn't provide adequate protection. He has been using straight Redline Heavy Shockproof and so has his other customers with dsm's so thats what i run now with the rebuilt trans. At first he told me it would be a little clunky until it warmed up but thats not the case even at cold temps everything goes in smoothly and ive never had any problems so am staying with straight redline from now on.
 
I'm using the pennzoil, it made a very significant improvement. I was going to go with BG but I talked to Shep and he reccomended Pennzoil. It does shift better when it is warm. I'm willing to try anything so, I'll try the redline next time.
 
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