G56 oil

[GAmes]

I've done a search and found no reference to this. I recently acquired an early model G56 from an 06 to install in my 97. I bought it in Dallas and immediately went to Standard Transmission in Ft. Worth to have it checked out. After they declared it a good transmission they advised me NOT to use ATF because most of my miles are towing. They recommend 30 weight synchromesh oil. Any one with a pro or con?

 

[Motorhead]

I have wondered if that might be a better choice also. I tow alot with my '07. Is 30wt synchromesh the weight used in the NV5600?

 

[AWay]

I tow heavy alot and have used only Amsoil ATF in my G56. Absolutly no problems and she shifts like butter.

 

[WStephens]

I have the G56 and have only used ATF and I have towed crosscountry and have not had any problems. I also have a Trans Temp Gauge and the Temp have been fine even towing in the Mountains of the East and the Rockies with not problems.

 

[seafish]

I am positive that sticking with manufacturing specs for ALL gear and motor lubes is a dam good idea. ((It's probably one of the few areas that HBarlow and I agree on. :-laf:-laf))



They are the ones who have done the design engineering and they are the ones who have to cover failures within design parameters under warranty--



I would consider switching only if ST is going to offer you a lifetime warranty on that transmission rebuild...



I am NOT suggesting that your transmission is still under warranty, or that the rebuild should get a lifetime warranty, ONLY that manufactures spend tons of money and time on design parameters and lubrication parameters and have to back that up with a warranty.



Just my . 02 ... .

 

[GAmes]

I agree that the manufacturer spends lots of time and money on R & R. However, they don't test the final product like we do, only by the design parameters. ST sees transmissions that hotshotters and ranchers use. They also have a reputation to uphold, so handing out advice that could cause failure is not in their best interest. They do warranty their work, however they did not do anything to mine other than inspect it and spin the input shaft in all the gears with a high speed 1/2 inch drill while listening for unnatural noises. They quit selling Syntorq for the NV4500 years ago and switched to Amsoil, with no ill effects, so I'm pretty sure they have done their homework about compatibility. Has anyone even heard of using something other than ATF?

 

[steved]

The only thing I will add is that Royal Purple states on its SynchoMax that it can be used in manual gearboxes in place of ATF. I've used it for over 100k in my 04. 5's tcase, but that's a lot simpler box than a G56.



I would hazard a guess that they are thinking a manual transmission fluid is a better idea than a automatic transmission fluid... the manual transmissions fluids boil down to the synchromesh-type fluids: Royal Purple SynchroMax, Redline MTL, Amsoil MTF, Pennzoil Synchromesh, etc.



But I would wonder if a fully synthetic ATF wouldn't be just as good a choice? Maybe add the fastcoolers for added volume??

 

[HBarlow]

I am positive that sticking with manufacturing specs for ALL gear and motor lubes is a dam good idea. ((It's probably one of the few areas that HBarlow and I agree on. :-laf:-laf)) ... .....

I'm grateful you agree with me on at least that one issue.

 

[GAmes]

I have a set of fastcoolers on my NV4500 and do plan on using them if they will fit. The sides of the G56 are vertical so I don't know if the coolers will clear the floor board, the 4500 angles down. I also read about two different locations for fill plugs and the notion of overfilling. I have two fill plugs on mine. One is level with the second bolt up on the PTO cover and the other is about two inches from the top of the transmission (at least it looks like a fill plug). Any insight on that? Also, what is the normal capacity?



Harvey, I recommend you continue using ATF:-laf

 

[Motorhead]

Somebody correct me if I am wrong but I think the upper plug is to be left alone. I don't remember if it housed a detent or something.
Pretty sure of myself..... ehhh

 

[tsawwassen jim]

g56 transmission fluid

I believe that the atf +4 atf fluid is used because of the syncro rings. The inner surfaces of the rings that grab the synchro gear are covered with a brass friction material. If you used regular gear oil it would defeat the purpose of this material that needs to slip slightly as you shift into the next gear. I would stick to the ATF +4



t-jim

 

[WStephens]

I have a set of fastcoolers on my NV4500 and do plan on using them if they will fit. The sides of the G56 are vertical so I don't know if the coolers will clear the floor board, the 4500 angles down. I also read about two different locations for fill plugs and the notion of overfilling. I have two fill plugs on mine. One is level with the second bolt up on the PTO cover and the other is about two inches from the top of the transmission (at least it looks like a fill plug). Any insight on that? Also, what is the normal capacity?



Harvey, I recommend you continue using ATF:-laf

I have a pair of coolers on my G56 that I got from Geno's and they work just fine not interfearance at all.

 

[GAmes]

I believe that the atf +4 atf fluid is used because of the syncro rings. The inner surfaces of the rings that grab the synchro gear are covered with a brass friction material. If you used regular gear oil it would defeat the purpose of this material that needs to slip slightly as you shift into the next gear. I would stick to the ATF +4



t-jim

Thanks, but synchromesh is not "regular gear oil". Although it is synthetic, the Royal purple I put in the differential is gear oil. Synchromesh, as I understand it, is formulated to be compatable with synchros. I'm still on the fence about this. I can tell you, I am dang tired of replacing transmissions.

 

[HBarlow]

Gary,

How's the G-56 retrofit project moving? Does the G-56 mate with the OEM bell housing on your 12 valve engine?

Does the hydraulic clutch slave cylinder match up with the new clutch and throw out bearing?

Does the tranmission top plate and shifter location match the hole in the floor?

Will you have to cut or lengthen the driveshaft?

Give us a progress report.

 

[steved]

Of the three common synchromesh fluids... RP is the thinnest, Redline is the thickest, and Amsoil is right about the middle.

Maybe a call into one of the suppliers is in order? And maybe ask Standard Transmission to specify what "brand" fluid to use in place of ATF?? I believe a "30-weight" oil would be almost any synchromesh fluid?

 

[GAmes]

Gary,



How's the G-56 retrofit project moving? Does the G-56 mate with the OEM bell housing on your 12 valve engine?



Does the hydraulic clutch slave cylinder match up with the new clutch and throw out bearing?



Does the tranmission top plate and shifter location match the hole in the floor?



Will you have to cut or lengthen the driveshaft?



Give us a progress report.

Transmission is locked up in the garage while I trek to AZ. The G56 has the bellhousing as part of the transmission, much like an automatic. Hydraulic clutch slave will transfer over. Shifter location is good and the driveshft does have to be shortened, however, the seller is trying to find the original driveshaft from the 06 donor, so if he can produce it I may be able to use it. I haven't ordered my SBC clutch yet. Member ewcmr2 has done this upgrade on his 97 and has given me loads of info, and pictures. He has posted most of the specs, but I will re post them as I get into the project.



steved, ST uses Amsoil. I was hoping to find someone else who has gone to a 30 weight synchromesh oil. Not that I don't believe the guys at ST, I'd like to get another member's feedback.

 

[SRadke]

I did some low mileage bearing analysis with different kinds of oil in my nv4500 some years ago. The sum of the results are that you will never find Redline MT-90 or MTL in anything I own again.

 

[SBeretz]

I have ran plain old ATF+4 for 82K miles in my G56 pulling a large toy hauler and trailers quite a bit. transmission shift really well and seems to be holding up the way it should. I changed it out at 50K and will do the same thing at 100K. This time I may use AMSOIL ATF+4 but it depends on how I feel that day. Good luck, great transmission in my opinion. Very easy shifting and seems to be pretty strong, and has great pulling ratios. Scotty

 

[steved]

I did some low mileage bearing analysis with different kinds of oil in my nv4500 some years ago. The sum of the results are that you will never find Redline MT-90 or MTL in anything I own again.

Neither MT-90 or MTL are meant for the NV4500...

 

[Regcabguy]

After reading the article in the new TDR concerning the G-56,I spoke to one of the guys at ST. For my situation(constant 2000# camper load and warm climate) they do recommend the RP Synchromesh. I've used Amsoil Universal ATF for 24,000 now. I'll listen to some more feedback before I make a move if any. The Amsoil gave me marginally better cold weather shifting performance.