Weight of a Synchromesh?

[deeter16317]

I'm running Redline MTL. I've ran about every synchromesh fluid in this trans, some work better than others, some last longer than others...Redline seems to work the best, so far.

I read on another forum about a guy running a 50w transmission fluid (I believe it was a Mack or Mobile trans fluid) in his synchromesh-spec'd trans with good results. I have been looking at Schaeffer's 50W trans oil, mainly since I can get it from a local distributor.

Thoughts?

 

[MGregoir]

Synthetic 50W works great in ten speeds but I have no clue about automotive transmissions.

 

[tom slick]

A 50w transmission oil is about the same as a 75-90w gear oil, thicker then your current MTL. If you are looking at #742 notice that it is specifically for transmissions that don't require EP and those transmissions don't have syncros.

 

[MolaKule]

deeter, I think you are referring to Powershift manual transmission fluids for heavy duty trannies.

These Powershift fluids are approx. 9 cSt higher in viscosity at about 18 cSt@100C, (much thicker) than the mtl synchromesh fluid.

A typical synchromesh fluid for cars and light trucks (Such as GM Snnchromesh and Pennzoil and Texaco Synchromesh) is approx. 9.5 cSt. Redline MTL is about 10.5 cSt.

Redline MT-90, as per their charts, is thicker yet at about 14.5 cSt.

Stay with what you have if it shifts well.

It would help us if you stated the type of vehicle and engine/tranny.

 

[D-Roc]

What vehicle application, Steve?

 

[RedOak]

I have the 2004 Silverado that is having all drive train fluids changed Thursday. In the 5 speed box in calls for gm syncromesh which is 5w-30 GL-4 lubricant. The rear end calls for synthetic 75-90. I am going to use Valvoline synthetic, and the front diffy calls for 80-90 conventional gear oil. I told them to stick with valvoline conventional gear oil. The transfer case will also be changed it calls for Dex 3. It is my company truck, and is going to have to last a long time. Almost have 120,000 miles on it and it will need to go 250,000 before we take it off the road. I wanted to use a bit higher quality fluid like amsoil or redline but need to keep spending in control in these tight economic times.

 

[MolaKule]

IS this a SIlverado 1500, 2500, or 3500 and what engine?

Most of the NV4500's require a synchromesh 75W90 mtl fluid.

 

[RedOak]

Silverado 1500 v-6 vortec. I have to give the garage the correct gm part number so they can order napa or valvoline synchromesh. I believe it must be a GL-4rating per the owners manual. I would love to have redline in it and may go down to advance in the morning too see if they have some. I am getting some grear chatter through the shifter and would hope the redline will help it. The company will only pay for over the counter brands so it would be at my expense.

 

[aquariuscsm]

Originally Posted By: RedOak
Silverado 1500 v-6 vortec. I have to give the garage the correct gm part number so they can order napa or valvoline synchromesh. I believe it must be a GL-4rating per the owners manual. I would love to have redline in it and may go down to advance in the morning too see if they have some. I am getting some grear chatter through the shifter and would hope the redline will help it. The company will only pay for over the counter brands so it would be at my expense.


If the Advance there doesn`t stock Redline,they can order it for you and have it the very next day.

 

[MolaKule]

Apparently the V6 could be attached to either an NV4500 OR an NV3500 mt. If the transmission is an NV3500, it requires an ATF which would imply something like RP Synchromax, but preferably Amsoil MTL, Pennzoil Synchromesh, or the GM/Chrysler Synchromesh. If the tranny is an NV4500, then a higher viscosity synchromesh such as Redline MT90 OR Amsoil MTG should suffice.

So find out the exact transmission type and use the proper viscosity fluid.

 

[RedOak]

Yes Molakule it requires GM Synchromesh which they had to order. It is the NV3500 manual transmission. I watched them pull the cover from the rear differential and it was amazing how clean it was. When they gave me this company truck to run I had no records of maintenance other than motor oil changes. I thought that GM used the purple colored gear oil in the differentials. Anyway, the gears looked like new, no metal shavings on the magnet or the housing. It looked like a complete new unit it was so clean. The old fluid was still very clean and no visible wear on any gear teeth. I was amazed how it looked on a truck with well over 100,000 miles on the clock.

 

[deeter16317]

Originally Posted By: D-Roc
What vehicle application, Steve?



The 5600...moot point now, truck is going to be traded for a subaru.