1995 6 speed Transmission Oil ?

[JimBobC4]

ok. I just got back from the GM dealer and purchased 4 quarts of what I "think" is supposed to go in the transmission of my 1995 6 speed.

The guy that sold it to me wasn't the sharpest knife in the drawer. He made me very nervous. In the end we had like 5 differerent bottles of oil on the counter. With 1 being a very very old quart of synthetic 5w30.

I now have 4 quarts of GM Synchromesh Transmission Fluid

Part 1 #12345349 GR.8.800

Is this the right stuff ? or did the rocket scientist at the parts counter screw up?

 

[twiget]

GM dosent specify an interval for changing the oil in a ZF-6, so I'm surprised that your "rocket scientist" was able to find replacement oil on the shelf.

When I replaced the oil in my '96's tranny, I did some research and found that ZF recommends the oil that BMW uses in it's E39 M5 engine. The look the guy at the BMW parts counter gave me was priceless when I told him I wanted the oil for the transmission of my Corvette.

I think I've still got a quart of the stuff on my shelf in the garage. If it's still there, I'll post a pic or two when I get home.

Jason

 

[Hib Halverson]

The original GM lube for the ZF S6-40 was a Texaco Havoline 5W30 engine oil.

Texaco hasn't blended that product in a number of years and when it stopped, GM replaced Texaco as a supplier and marketed a 5W30 lube from another source. I remember GM's "synchromesh fluid" as being the recommended lube for the Muncie transaxles in front-drive cars. I'd check very carefully...even go to a different dealer. You need to order the stuff by your model year, not just as a lube for the trans in your Corvette.

ZF has also suggests a Castrol engine oil for the S6-40, but I've heard that 1) it's very expensive and 2) that Bill Boudreau (overhauls ZFs as the "ZF Doc") tested it and felt its durability wasn't very good. I recall he told me it needed a change after 10,000 miles, based on a spectrographic analysis.

Or, you can use the lubes I've used in both my ZFs for nearly a decade. For normal street use, I put in Red Line MTL. For really aggressive driving in hot weather, I use Red Line Light Shockproof. Both work quite well. Shift effort is slightly less than with the OE lube. They go 3yrs or 36,000 miles with no problems. In cavat...with Shockproof, when the trans is cold, it will shift a little hard, but as soon as the lube gets to 100 deg or so, it shifts like a knife through butter.

Lastly, this disclaimer...my comments about shift feel apply only to cars having no clutch issues. If your hyd. clutch is faulty or the clutch itself is not releasing cleanly, no lubricant in the world will fix the shift problems those situations can cause.

 

[twiget]

The oil I used was Castrol TWS 10W-60. Like Hib, I noticed a difference in the smoothness of the shifts. I do not remember how much the stuff was, but considering it was a special blend for BMW's M5 motor, it probably was not cheap.

Jason

 

[JimBobC4]

The original GM lube for the ZF S6-40 was a Texaco Havoline 5W30 engine oil.

Texaco hasn't blended that product in a number of years and when it stopped, GM replaced Texaco as a supplier and marketed a 5W30 lube from another source. .

The Texaco lube was exactly what the man put on the counter first ! It was in very old plastic bottles, yellowed from age. It actually had a little tiny Texaco emblem on the bottom. I thought the man was out of his mind.

Interesting.

Maybe it was me that was misinformed. :ugh

The second bottle he had was a 5w30 motor oil with GM emblem on it.
Said that was the second version. It was ancient as well.

Then he scooped up the synchromesh oil.

Also, the car shifts great already. I'm only changing the fluid for longevity purposes.

I will investigate the synchromesh further. I may even go with the Redline as it will most likely stay in for a long period.

Thanks everyone ! I do appreciate the replies.

I feel much more warm and fuzzy, then again maybe its the bourbon

 

[muddywaters]

Just a throw in, I used Redline MT90 in my 88 4+3, much smoother/easier/better shifting, in the 99 I used Redline D4, the improvement in the 6spd. wasn't that great.

 

[Hib Halverson]

The oil I used was Castrol TWS 10W-60. Like Hib, I noticed a difference in the smoothness of the shifts. I do not remember how much the stuff was, but considering it was a special blend for BMW's M5 motor, it probably was not cheap.

Jason

Just need to correct something here...I never stated that I've used Castrol TWS 10W60, as Jason implies, above.

I've never used or advocated to use of that product, as a result, it would have been impossible for me to notice a difference in smoothness of shifts with it.

As I said before, I have used some synthetic lubricants from another maker and, with them, I have noticed an improvement in shift feel.

I'll add that, to expand upon "muddywaters" comment about D4 ATF. Typically, when a C5 or C6 user goes from the stock Dexron ATF to Red Line D4, after a short period it takes the new lube to permeate throughout the gear box, there usually is a noticable improvement in shift feel. However...the C5/C6 seem to be more sensitive than other cars to air in the clutch hydraulics and if that happens, you can end up with the clutch dragging slightly even when the pedal is one the floor. If that situation is present, the trans will shift harder, no matter what lubricant you use. The moral of this story is, with C5/C6 you need to bleed the clutch every so often.

On a personal note, I use Red Line Superlight Shockproof in my C5 transmission and it was even better than D4 (which I also tested) as far as a shift feel improvement. In fact, I'm always amazed at how much more smooth that trans shifts since I went to that lube. That said, like all the racing lubricants in the Shockproof series, you do pay a small shift-effort price when the trans is cold but that goes away quite soon after you begin driving.

 

[Black Bart]

Here is a link to the ZF site.

http://www.zfdoc.com/

Here is part of what he says about the ZF

TRANSMISSION OIL (status) - Vascular flow of oil through the porous Phosphorus-bronze (Pb) material of each synchronizer is essential for effective British Thermal Unit (BTU) heat exchange occurrence. Frequent transmission oil changes will ensure lower Pb particle levels suspended in the oil. The ZF S6-40 6-speed transmission is lubricated by engine type oil. Manufacturer recommendations specify the use of GM P/N 1052931 (5w-30) or BMW P/N 07510009420 (10w-60) oil.
Approximate oil capacity of the ZF S6-40 is 2.2 quarts.

I have used the Redline MT oil and now have the Castrol and have no problem with either oil.
My engine is making 1178 HP so I work the transmission real hard.

 

[JimBobC4]

Here is a link to the ZF site.

http://www.zfdoc.com/

Here is part of what he says about the ZF

TRANSMISSION OIL (status) - Vascular flow of oil through the porous Phosphorus-bronze (Pb) material of each synchronizer is essential for effective British Thermal Unit (BTU) heat exchange occurrence. Frequent transmission oil changes will ensure lower Pb particle levels suspended in the oil. The ZF S6-40 6-speed transmission is lubricated by engine type oil. Manufacturer recommendations specify the use of GM P/N 1052931 (5w-30) or BMW P/N 07510009420 (10w-60) oil.
Approximate oil capacity of the ZF S6-40 is 2.2 quarts.

I have used the Redline MT oil and now have the Castrol and have no problem with either oil.
My engine is making 1178 HP so I work the transmission real hard.

I think the GM part number is no longer current. I believe the part number you have listed was the old 5w\30 stuff I saw at the counter. I think the newest version is GM P/N #12345349 . Apparently it has some type of friction modifier in it. However it is still 5w/30 oil basically.

Trying to get a straight answer out of GM is TOUGH though.