5 Speed Synthetic Lube?

[jeffscarstrucks]

Now that I can drive my truck again thanks to Turbo Al I was going to switch out the trans lube to 75W90 synthetic but I wanted to check with any one who might have some thought on it first. The truck is a 93 6.5 5 speed. I started to swith it out a few years ago but it seem that GM had an odd part number for the factory fill and no one seemed to know what viscosity it was and I never got back to it. The second part of this question; is it OK to remove the inspection/assembly cover on the side of the case since there is no drain plug? Thanks, JEFF

[Turbo Al]

Hi Jeff,

Thanks for the kind words. Glad you got it all together and running.

Originally the recommened (demanded actually) oil for the NV4500 was a 90wt syn. That got changed about 5 years ago to 75-90wt (I think) both are a GL-4 oil which has a lesser amount of sulfur/phoshphorus because of the POSSIBILITY of the sulfur attacking the light metals in the transmission.

Having said all that I have run a syn 75-90wt GL-5 oil for well over 100,000 miles with no ill effects so far.

It's your $2,000 trans you decide if you want to keep paying a lot of money to GM for oil or just put in the less expensive stuff from an autoparts store. I recommend changing it out every 50,000 miles.

There should be a drain plug on the passenger side bottom of trans just before the joint where the four speed has the OD 5 gear joined on.

No problems in taking off the inspection cover -- I can't remember if there is even a gasket on it.
Al

[LanduytG]

Amsoil has just released a new product for these trans. Its product code is MTF and is much cheaper than the Castrol SYn Torq or the GM stuff.
I beleive they are now shipping it.
Greg

[jeffscarstrucks]

Thanks again! the trans main cast housing has a place cast in it for a drain plug in the location you suggest but they didn't bother to drill it...must have been about quitting time. Taking the cover off will let me have a better look into the bottom of the case for debris so it can't hurt to spend a little extra time anyway. I really enjoy reading/learning this site and am constantly amazed at the wealth of knowledge held by some of the contributors. Thanks , JEFF

[Turbo Al]

Jeff, you are welcome

If you ever have some time on your hands a few good sites for info on the NV4500 are:
www.JBconversions.com (http://www.JBconversions.com)
www.newventuregear.com (http://www.newventuregear.com)
www.advanceadapters.com (http://www.advanceadapters.com)
I have done a fair amount of research on the NV4500 and all these sites are more than willing to answer questions on the trans. as well as having a LOT of info on the sites.
Al

[Turbo Al]

Jeff,
While working on another request for info I found the G.M. updated part number and the date it was revised:
GM # 10953477 syn oil 75-90wt Jan 20, 2001 (the OLD GM # was 12346191 90Wt syn.)
Al

[JohnC]

Remove the bottom bolt on the PTO cover to drain the oil. Don't forget to re-seal it before you reload!

[Hansh]

I have also run the 75-90W Amsoil Syn for 80k and had no problems.

[jeffscarstrucks]

Thanks Guys, next oil change is coming up so I'll do it then. JEFF

[Hubert]

Also look at http://quad4x4.com for NV4500 stuff.

I emailed Castrol looking for Syntorq and they gave me the standard reply something like its a performance synthetic lube bottled specially for GM and Dodge. I read they made a deal with GM/Dodge and they don't sell it retail by the quart. I have read you can still buy it from Castrol but the min is a 30 gal drum.

Quad4x4.com only recommended syntorq. They and other places buy it in bulk and repackage it. They sell it 2 quarts for $25.00 Standardtransmission.com wants something like ~$54 for a gallon. (Both are fair deals but shipping priced it back to dealer cost for me)

Also check a local dodge dealer thier part number is 04874459 which I found locally for $15.00 a quart GM wanted $22.18/quart. GM'ed again uhggg.