Transmission Fluid

[RT/ED]

I am a new member to VCA and have onwed a 95 RT/10 for the past year. The manual calls for Dextron IIE ATF. How is it that 75W-90 gear oil such as the Amsoil synthetic product is being used by other viper owners with success? It seems that the gear oil would much thicker and would not be suitable as a replacement fluid for the transmission. Any thoughts and or recommendations on this topic would be greatly appreciated!

 

[95Viper]

Use factory fill.

 

[Chuck 98 RT/10]

The TSB on NGR (dontcha love the alphabet?) called for an upgrade from Dextron to Mopar (not positive of the weight but somewhere's around 75W-90). Rear gear is much thicker, around 140W and SHOULD NOT be used in trannys.

 

[GTSPOWERED]

I just went to my local dealer and they sold the synthic gear lube not the auto type oil. they said that the gear lube will not hurt anything and will cut down on the noise.

 

[Chuck 98 RT/10]

I just went to my local dealer and they sold the synthic gear lube not the auto type oil. they said that the gear lube will not hurt anything and will cut down on the noise.

Gear lube? Are you saying rear gear? What's the weight?

 

[Tom F&L GoR]

I think this "gear" lube is also used for transfer case lube, and it's an 75W-85 grade. Web search says it's Castrol Syntorq LT and is available through General Motors (Part #12346190) and Chrysler (Part #4637579) dealerships, also at
http://www.standardtransmission.com/dodge.html

 

[Steve-Indy]

For a 95 Viper tranny, use Dexton III ( and NOT ATF+3 and NOT ATF+4)...OR after complete flush, some are using the NEW factory fill...Castrol Syntorque 75w85 ( or Mopar's Synthetic Manual Transmission Fluid...which is the same as the Castrol). Several of our members have had a GREAT DEAL of trouble getting the correct fluid from their LOCAL Dodge dealer...be careful.

 

[Ron]

Was told that the wrong fluid (i.e. anything but factory fill Syntorq or DextronIII, depending on year) will damage the synros.

Deviate at your own risk....

 

[Jack B]

A couple of interesting points. The Syntorque LT is a 75-85 weight oil, however, it has a pouring consistency of 30 weight oil. The dealer list is $21/qt. The oil can be bought in 16 gallon pails from a commercial oil distributor for approximately $400, or $6.25/qt - nice mark-up. The dealer should not be refilling with Dextron III, the current oil is Syntorque which is private labeled under the Mopar brand.

Take out the Dextron III, put in the Syntorque. The only negative is the trans shifts a little sluggish for the first few miles. With either one, a large number of trans problems can be traced to keeping your hand on the shifter (especially road racing while accelerating/deaccelerating) and loading the shift pads and eventually getting synchro wear. This can be eliminated or reduced by changing the shift pad material.

 

[Steve 00RT/10]

Amsoil is just over $9/quart and the transmission seems to run cooler than with the Castrol

Steve

 

[RT/ED]

I appreciate all the feedback and advise on correct transmission fluid for the 95 RT/10. It appears that it should be OK to run the AMSOIL 75w-90 gear oil in place of the Dextron IIE.

 

[Nasty 10]

<font color="red">Ams</font><font color="blue">oil</font> has confirmed it's fine to use their 75W90

 

[Jerome Sparich]

Dexron
Dexron
Dexron

There is no "T" in Dexron.

 

[Ron]

Wouldn't it have more credibility if Tremac confirmed that it was OK to use Amsoil?

 

[Steve-Indy]

Good point, Ron...ESPECIALLY come warranty claim time !!!

 

[Steve 00RT/10]

It is my understanding that typically, if a lubricant meets or exceeds certain testing standards--determined by the manufacturer, it will be satisfactory for a particular application. Amsoil meets or exceeds the requirements for all lubricants used in the Viper. In addition, they have a 100% warranty on their products. If,through testing of the lubricant, engine or mechanical failure is attributed to their products, they will replace whatever component has been damaged. I don't believe they have ever had to exercise this option---since 1972

Steve

 

[Bruce]

Here's what the factory rep told me on my 94:

FROM CHRYSLER FACTORY PAUL OSTER, FILE NUMBER ABOUT FLUIDS, 7081-836, USE MOBIL 1 SYNTHETIC ATF, IN TRANNY, 80W 90 SYNTHETIC LUB DIFFER. FLUID

I kept the file number for reference if something screws up. So far no problem.

Give the factory guy a call: 800-992-1997

 

[Skip White]

If you use Amsoil for the trans., great, use the Series 2000 75W-90 only. Its there top of the line. The diff calls for 80W-140 I thought. I do know the early Vipers called for ATF in the trans. and in later years they went to Castrol Syntorque, which is a 75W-90 synthetic gear lube. I don't know if the trans is any different,but the two fluids are very different. It would be great if the trans. would operate trouble free on ATF. The drag produced by a lube that is so much heavier must be terrible in the cold parts of the year, especially when it takes ever bit of 45 minuets of driving to really warm up the trans. Then the heat dissipation factor of using heavy stuff is not to good when compared to ATF. There is a type of lube out there, that would probably be the greatest of all, for all around protection, its what is in every big rig trans. on the road, well most of them, its 50 weight synthetic trans fluid. Amsoil makes this and so does Eaton. If a Viper used ATF at one time, and found it to be to light, they should have went to this weight of lube, instead of jumping all the way up to 75W-90. I think I may try it in my Viper Trans. I'll talk to the factory tec. people at Amsoil first and see what they think. Dissapation of heat is a very good thing for trans. Thats the primary reason most trans. are using this. I wonder if the tolerences are different in these units that use such light fluids??? Anyone out there know the answer to this?

 

[Tom F&L GoR]

skipwhite, your comments about the viscosity grades are incorrect. The "75W" or the "50" or the "90" are merely labels used for a certain viscosity range and have nothing to do with the viscosity value itself. Further, the gear oil viscosity grade system and the engine oil viscosity grades are not on the same scale.

The SAE 50 drivetrain oil is a fluid developed for transmissions, hydraulic systems, wet brakes, and more, and uses the engine oil viscosity grade classification. The viscosity of an SAE 50 (at 100C) is between 16.3 and 21.9 cSt (and for example, Texaco Transmission &amp; Drive Train SAE 50 is 17.4 cSt.) The 75W-90 gear oil for transmissions and final drives uses the gear oil classification. The viscosity (at 100C) is from 13.5 to 24.0 cSt (Chevron 75W-90 gear oil is 15.5 cSt.) So nominally, these two fluids are the same viscosity and actually the gear oil product could be "lighter" than the SAE 50.

Further, the SAE 50 has no requirements at lower temperatures, while the 75W-90 does. The SAE 50 would be worse in cold weather than the 75W-90. And in fact, the visocity at 40C of the SAE 50 is 180 cSt, while that of the 75W-90 is 117 cSt.

 

[RT/ED]

I decided to switch all fluids over to the AMSOIL 2000 series products after researching their webiste and product comparisons. QUESTION: When switching from the Dexron IIE to the 75W-90, is it necessary to perform a complete transmission flush. If so, how and what is used to flush the trans? Thanks in advance for any help on this.