Pennzoil Synchromesh breaks down rapidly

Caithness · 01-04-2007, 09:32 AM

I've been having shifting issues for the last month or two. The car was getting very notchy in low rpm around-town driving but was fine at high rpm when I was beating on it. I checked a few things and just fixed the problem completely by draining and refilling the tranny with fresh Synchromesh.

This stuff was less than one year old when the problems started (probably 8 or 9 months) and had well under 3000 miles on it. It looked a little runny draining out but I didn't pay close enough attention to it to make that a good data point. I'm amazed that this stuff broke down so quickly- and a little disappointed. I'm going to look into other options, like a BG II/Neo RHD mix I've heard good things about.

I think the Florida heat may play a part, and my tranny builder did recommend changes every 5000-6000 miles, but 2500 miles is just ridiculous.

2gAWDTalon · 01-04-2007, 09:59 AM

I am also in Florida and it is hot here. If you beat on your car the syncromesh blends are just to thin for us. I am using 1 qt. Redline Shockproof Heavy and the rest (1.5 qts.) Redline Shoockproof light. This is a fully synthetic oil so it will last longer and has a great film thickness for protection. You can get it is Orlando from Titan for $8.50 a QT. I have a friend trapping 145 in the 1/4 and he was using all Shockproof heavy, but now he trailers the car and it dosent get enough chance to heat up so he started adding 1 Qt. of light into the 100% heavy mix. Shifts great at high RPMs and offers protection, somthing I dont think the syncromesh is thick enough for. I am new to the Shockproof, but I have been told it last alot longer. I think the BG2 may last longer just because it is synthetic, but is still to thin and dosent offer good protection. This is by far not the first time I have heard of syncromesh not lasting long.

http://www.titanmotorsports.com/shgeoil.html

mavisky · 01-04-2007, 10:39 AM

I'm experiencing better results with some crappy walmart tranny fluid than I ever did with Syncromesh, especially the Penzoil stuff. It also seems to work better with my phantom slip as well.

Defiant · 01-05-2007, 05:35 AM

I should get around to that. I think there's 60,000 on the batch in mine. I'm not very hard on the gearbox, and double-clutch all downshifts.

There shouldn't be any difference between GM's and Pennzoil/QS's branding on the bottle. It's the same product. But the effers still haven't sent me a damned royalty check.

We had a week over 105º here last July, and regularly get a month of 100º+ days. But, it's a dry heat. Except for in my undies.

DGajre777 · 01-05-2007, 06:50 AM

Did you put Synchromesh in your tranny, x-case and rear diff?? I use Synchomesh in my tranny and Redline Heavy Shockproof gear oil in my transfer case and rear diff. I'm in Florida, no issues (yet).

2gAWDTalon · 01-05-2007, 04:51 PM

I am running redline shockproof heavy in the T-Case, Rear end and the previously mentioned mix of shockproof in the trans (1qt. Heavy and the rest Light). It just needs to heat up before you go slamming gears.

dnhieu · 01-05-2007, 05:31 PM

Im using 2 bottles of royal purple and 1 bottle of castrols 80-90w elcheapo and it shifts great while its hot outside but not as good when it gets a little cold...

Caithness · 01-05-2007, 10:33 PM

Defiant, I'm amazed you've gotten that far on Synchromesh without any problems. It makes me want to blame this problem on something else, but the car is still shifting better after several days so the fluid was definitely to blame in my case.

I'm running Shockproof Heavy in the rear diff and transfer case. It was one of the first things I changed out after I got the car and I've only put 10-15k on it in 4 years, so it's still in there. I'm not sure what sort of interval you're supposed to change that stuff out on, my guess would be every 30k but I should check the manual. I've never drained it so I can't comment on how it's holding up. Less direct feedback than with the tranny.

I think I might try that Shockproof heavy/light mix if I have to change this stuff out again before I sell my car. The one major downside to the Neo RHD is that it's really friggin' expensive, and the Shockproof is only 8.50 a bottle.

Defiant · 01-06-2007, 02:45 AM

Well, I drive fast, and I corner fast, but I'm pretty easy on gearboxes. Over a quarter-million miles on my Datsun 2000, 150K on its current transmission. No issues with the Talon, yet.

jongreene · 01-06-2007, 12:06 PM

I'm having the same issues with the P.synchromesh. I don't do hardshifts EVER and at around 4k the Pennzoil's breaking down to the viscosity of water.

missouri_dsm · 01-06-2007, 12:22 PM

There was a local that was having trouble getting the car to shift into second. He replaced everything from the slave cylinder, master cylinder, adjusted clutch, bled the clutch about 1000 times and checked his clutch pedal assembly. Finally changed his old synchromesh with a different kind and everything was buttery smooth.

Morphius · 01-06-2007, 03:25 PM

Quote:

Originally Posted by Defiant

I should get around to that. I think there's 60,000 on the batch in mine.

I've got 50K+ on syncromesh in my trans. It shifts like it did with fresh oil.

Those of you that seem to make a difference with an oil change must be injesting some water in the trans or something to help break it down.

nuclearpenguin · 01-17-2007, 01:46 PM

Wow, ironic...

I just started having a grinding issue\"hard to get into gear" problem in my transmission yesterday. I'm pretty devoted to synchromesh after running it in my probe, but I must admit I drained it out yesterday and it was as good as water, after only 8 months (about 6,000 miles)

No one around here sells Redline or the Synchroshift so I went ahead and put in some Valvoline "Dura-life" (whatever their synthetic is) into the transmission. Haven't got to drive it much yet and test it, but we'll see.

Apeximprt2nr · 01-17-2007, 03:36 PM

Hmm that's weird. I run BG Syncroshift II and it shifts the same as it was when I put it in a couple thousands miles back. I live in Jersey where it's really hot or really cold. Shifting is obviously better when it's warm but I've yet to change the fluid. I may to see what shows up.