Toploader Fluid?

[Timbo]

I have a rebuilt toploader and am wondering what fluid everyone else is using? After snooping around the internet and after contacting David Kee, Toploader Trans.Inc. They recomend draining it and using two quarts of Pennzoil 80W-90 gear lubricant every 20-25,000 miles. Just wondering? But with all the synthetic lubricants and all just wondering what would be best? Thanks in advance.....

[Bruce Edwards]

Any 80-90W gear oil is what the trans was made for. I would and do stick with what it was made to use.

[clayfoushee]

David Kee also discusses synthetic on his site. He says it works fine for some and not for others. I agree it's probably best just to stick to the standard stuff.

[blykins]

I wouldn't use synthetic or anything with less viscosity than the gear oil above...the synchros in the Toploaders work by friction....if it's too slick then the synchronizer rings will have trouble getting the gear to match speeds with the synchro hub.

[era427tp]

I've used Valvoline syn-power gear lube for the past five years,the main difference is that it shifts much easier.

[rdorman]

I just changed the fluid this weekend swithing from standard petrolium based lube to Red Line MT90 synthetic. While it is true that the syncronizers work with a certain amount of friction, Red Line knows this! And they have formulated for it. The shifts are now slightly lighter and smoother than they where before. I would personally recommend MT90.
Rick

[CHRIS POTTER]

I tried Mobil1 synthetic in my toploader. It didn't work well, a lot of grinding between gears, but, it did shift easier. I put standard 85/90w in it, no more grinding. Sounds like Rick has the hot setup with Redline! I will probably give that a try. Thanks, Rick!

[Goober]

My cousin has a 66 fairlane GT which he purchased new. He now has over 250,000 miles on it with one engine rebuild. At 85,000 he drained the top loader and reloaded it with standard 90 w gear oil again. I agree with Bruce Edwards on staying with what was recommended. He has never had the transmission apart, not even for syncronizer rings. I'd say that's pretty good.

Just my 2 cents. By the way, it's a big spline toploader behind a 390 FE.

Mark

[Cal Metal]

Goober:

The 390 FE motor originally came with a 28 spline, as opposed to a 31 spline big out tail. It also used the 1-1/16 input as opposed to the 1-3/8 inch style. The 390 could be had with either the wide or close ratio gear sets; the 427/428/429 came only with close ratio sets. David Kee does make a wide ratio big in/big out gear set which is really great for guys with 3:36 and 3:55 rear end ratios.