Engine/Transmission (1994 - 1998) Castrol Syntorq

[jmitchell]

Are people getting away with using something else (read "less expensive, more readily available) than the Castrol for their NAV4500?.

TDR writers have recommended changing the oil once in a while and the owner's manual states that it never needs changing. What is the experience in the field?

I don't really "use" my truck. I just drive it. If the recommendation is to change the transmission fluid once in a while, at what interval?

 

[QRTRHRS]

jmitchell,



Welcome to the TDR. Oil? Depends on who you ask. I would say the most often used alternative is Amsoil 2000 75-90. There are others of course such as Redline. If you search the archieves about this, you will come up with a hoard of threads. I had been running Amsoil in mine. When I lost 5th gear, I decided to go with a rebuilt with fully splined 5th gear shaft from Standard. Warranty in mind, I stayed with the Syntorq. I won't say anything either way about the Amsoil except this. I have the passive filter kit that Geno's sells. It was covered with a waxy parafin like smeg when I pulled out the old transmission. Good-bad-indifferent? I don't know.



If you wish to stick with the factory recommended Syntorq, seek out Standard Transmission for a more reasonable price of about 54/gal.



Intervals? I would say 50k for just "driving it".

 

[mfelix]

syntorq or API SEVICES GL4

jmitchell I ASK THIS SAME QUESTION AND GOT ALL KIND OF ANSWERS. #1 MOPAR WANTS OVER $ 22. 00 A QUART FOR THERE GEAR LUBE #48774459 THERE CRAZY. I PUT VALVOLINE SynPower FULL SYNTHETIC 75-90 GEAR OIL FOR $4. 90 A QUART . THE STUFF I TOOK OUT OF MY 4500 WAS BLACK ABOUT 45000 MILES ON THAT TRANS. CHRYSLER CORP. PUT A NEW ONE IN AT 52000. FRONT SEAL BLEW OUT . REPLACED CLUTCH & TRANS. HEY IT SHIFT NICE NOW SINCE I CHANGED THE OIL IN IT. I DONT KNOW IF THE OIL IS BLACK WHEN ITS NEW BUT ITS BLACK NOW. VALVOLINE IS GOLDEN IN COLOR. BY THE WAY I TOW 36 FOOT GOOSE NECK CAR TRAILER EVERY WEEKEND OVER THE MOUNTAIN TO RACE. DO WHAT YOU THINKS RIGHT FOR YOU. I DID BY THE WAY THAT GEAR LUBE IS API SERVICES GL5. GOOD LUCK

 

[Joseph Donnelly]

A gallon of Syntorq from www.standardtransmission.com (800-std-tran) will be about $65 with shipping. I did some horserpower drag tests and noticed how fast the transmission oil came up to temperature using several lubricants. The only alternative that I like is Torco RTF. I would guess the Castrol (GL4) is easier on the synchronizers and the Torco may be better for preventing gear breakage. I've used both and my only reservation against the Torco would be if you are in a hot humid area where the oil gets very hot from towing, etc. (makes the additives more "active" to attack the bronze synthros). On the other hand, some folks have broken 3rd or 5th gear usually and they may be better served with the GL6 Torco Racing Trans. Fluid. One trans got a crack in the tailhousing and most of the oil leaked out. The few teaspoons of Torco left were still fresh and clear despite the heat that eventually locked up the trans.

 

[RKohn]

Royal Purple...

is what the dealer here sells. Meets GL-4 and GL-5 and supposed to be good for bronze parts. $8 per qt,

 

[Texas Diesel]

Ditto on the Royal Purple, my 4500 loves it.



It is the Royal Purple Max Gear 75W-90 and it is safe for synchros.



I love it in mine.



If you cant find it locally, order it through JC Whitney.



I think it was $6-7 / quart.

 

[nfox]

Royal Purple 75-90

My truck has 125,00 miles on it and changed the fluid in my nv4500 over to royal purple and it seems to shift alot better and it cost $8. 32 a quart verses $23. 00 for the syntorq.

 

[Sled Puller]

The Amsoil Series 2000 75-90 has been very popular in that transmission. My personal results, have been great.



I would suggest with any lube, 1 year or 35,000 miles in that transmission, and throw a set of Fast Coolers on, for good measure.

 

[RKohn]

Tejas and Nfox,



Are you guys running it if the diff too? If so, with or without the ls additive?



I've been happy with the Valvoline, but it'd be nice to cut down on the # of different bottles on the shelf, maybe even buy a 5 gal jug.



rick

 

[Texas Diesel]

No, I'm running Mobil 1 in the diff but at the next change I'm switching to the Royal Purple.