7AFE Transmission a bit notchy... Options

[englishdas]

The more I drive the car, i.e over 10minutes, the notchier it gets slotting back down from 3rd to 2nd or 1st. It's not terrible, but it's not right.

I reckon the condition of the Trans oil is my first stop, and have tracked down a supplier of MT90 'EBAY REDLINE MT90'

Now, I know that the capacity of the Trans is 2.6L (thanks, Rusty for C52 Trans Thread) So do I need 3 Bottles of this stuff, and (obviously not over-)fill it purely with MT90, or do I measure out standard 75w90 gear oil at about £7 per litre, and add the full bottle of MT90 to make up the 2.6L?

Am I making sense and/or overcomplicating it?

[Smaay]

yeah you are way over complicating it. get 3 bottles and fill until it comes out the fill hole

[VavAlephVav]

people say that MT90 works the best, IDK if there is any benefit in mixing it especially since most gear oil is GL-5, the GL-4 stuff is supposed to work better for the synchronizer.
I have seen a number of articles that say if you overfill it will drag a bit. 2.7 or 2.6 is good to shoot for but it should not be dripping out the fill hole, if the car is level you might
be able to stick your finger in to the first knuckle and feel the oil level. better to measure it.

[SwissFerdi]

Mine has third gear synchro wear, but this is apparently common. I filled entirely with Pennzoil Synchromesh, and the grind is mostly gone. The SM fluid shifts very smoothly. Now I've got further notchiness like you describe, sometimes it won't go into first. I think this is more temperature-related though, as with the recent cool spells it has been getting worse and improving as time goes on. I'm tempted to partially drain and add a bit of 75W-90.

And like Smaay said, just fill until it starts puking it back at you. Now I don't know if exact leveling makes a difference, I imagine it does...the first time I filled the car was on four jack stands, so reasonably level. The second time I only had the car on the scissor jack but I cranked it down so that the car was level (stupid way to work under a vehicle, by the way, I do not recommend).

This post has been edited by SwissFerdi: Feb 6, 2014 - 7:30 PM

[englishdas]

The second time I only had the car on the scissor jack but I cranked it down so that the car was level (stupid way to work under a vehicle, by the way, I do not recommend).

LOL who of us hasn't done that though at some point....

Thanks for your help, lads.

Will get 3L of the MT90 and go with that. Pennzoil products arent readily available over this side of the pond.

I expect nothing but immediate results and warp-speed gear changes.

[VavAlephVav]

this is the article I found back when I was researching the same issue with mine (I'm actually sitting on 3qts of Pennzoil synchromesh its just too damn cold to mess with rtm)
http://www.rsgear.com/blog/2011/5/23/under...n-failures.aspx

this guy sounds like an old-timer pro and he's like "damn kids don't know what their doing, you can't use a racing clutch on a street car, you can't install a short shifter and get the synchronizer to work right.."
it's kinda funny, but he seems to know quite abit about the subject. either way this is his discourse about over-filling

"The amount of lubrication is also critical for shift timing. Overfilling a manual transmission will cause fluid to leave from the vent but will create windage problems. Windage is the effort needed for the gears to turn through the oil level. Dry sump race motors make more horsepower than a stock wet sump motor because the crankshaft is not fighting the oil in the bottom of the pan. Think of it as trying to run on a beach.
It takes little effort to run on the hard packed sand near the tide line, but a great effort to run through 6 inches of water in the surf. When a manual trans is over filled and the driver makes a shift, the gear trains slows down very quickly when the clutch is depressed because of the fluid drag, altering the synchronizer timing and causing shift issues.
A classic case of this was the Tremec 3650 series of 5 speed transmissions where the fill plug was actually designed too high in the case. On these units you cannot" fill to spill", but to ½ inch below the fill plug level for proper operation."


I have no way to verify how accurate this is for our specific transmissions though

[englishdas]

Thanks Vac, that's always what I thought, its a certain level for a reason. 3 bottles of mt then, measured to 2.6l.

Cheers for the info, all