Hi guys, this is my first post so bear with me.
I have a 1999 Chevy s-10 truck. I just bought it and have been going through it changing all the fluids, plugs,etc. I want to change the tranny fluid. It is a 5 speed manual with a 2.2 4 cyl. eng. My Hanes manual says the 94 and 95 models take dexron auto fl. The rest take either Friction Modified Synchromesh part #12377916 or Syncrhromesh Transmissiom Fluid part #12345349 or equivalent. The Chevy dealer ran my VIN and said I use the Friction Modified Synchromesh fluid. I go to pick up the stuff and the part #12377916 (friction mod.) dosnt say ANY thing but manual trans. fluid. The plain syncromesh fluid just says syncromesh. The guy behind the counter says all they ever use the the reg. synchromesh. They have to order the other stuff. A guy at the tranny shop tells me if it calls for the modifier you should use it. Makes since to me. I wonder if over the years they have made it all in one now and reg Syncromesh fits the bill for all. God this is confusing. I would think that if it had a friction modifer in it, it would say so and not just manual trans. fluid. Can some one please tell me what I should use before I pull what little hair I have left out.
Sorry this is so long and confusing. :banghead:

YES IT IS CONFUSING FOR SURE.

You need to ID which 5 speed you have.
There are 3 different 5 pseeds.
NV-1500 and NV3500 used in s-10 and also a NV 4500 used in the bigger trucks.
The dealer should be able to decode your vin no. to ID transmission.
The NV1500 calls for GM synchromesh fluid 12377916 with 5% friction modifer gm part 12380672 to be added to the fluid.

If the dealer does not have the right stuff for it have hime get it for you.
Good luck MT
The NV 3500 transmission calls for GM 12345349 synchromesh with no friction additive.

And you will be luckie if they have not changed the numbers on the stuff.

Yes I have the new-venture 1500 which calls for the 5% frition modifer but it seems like none of the dealers around here have ever heard of the frition modifer. They all say they have never used that and all they use is the regular sychromesh.
I told the guy so if I were to bring my ride in for a tranny service, yall would use the reg. sychromesh then, right???? and he saying yea!!!!!!
My book says that the part# 12377916 is the right stuff but it dosnt say ANYTHING about a modifer. It dosnt even say Sychromesh on the bottle. It says manual tranny fluid on the bottle???????? That sounds like plain jane ole fluid to me. Good lord I have done gone and confused every thing again.
If I just went strickly by part# I would get the 12377916 but not saying Sychromesh or frition modifer on the bottle has got me baffled.....
Thanks for helping me out on this one....

As near as I can figure you us the 12377916 and add 5% 123806672 to it.
Can the dealer order or get the 12380672 friction modifier?
If not check another dealer.
MT

Sounds good to me...thank you so much for your help!

Sounds good to me...thank you so much for your help!

You are welcome and good luck
MT

My NV1500 has been on a steady diet of 12345349 for about eight years and 50,000 miles with no additive and no synchro problems.