Thread: 85w-140w vs 75w-90 for winter?

About to change my clutch in a minute, and was wondering about gear oil. With winter coming up, would I be better off putting 75w-90 back in? Would the 85w-140 be too much for winter? I have both on-hand, and am debating which one to use for winter. I'd rather use the 85w-140, but am concerned about it being like using honey in the gearbox with at, or below freezing temps outside.

I've done full winter with full 85-140. When you first start it in the morning and let the clutch out it will bog way down for a bit, and be pretty stiff to shift until it warms up. If I were you, I'd recommend maybe doing a mix, 75/25 maybe (mostly with 75-90), or maybe a 60/40.

So it's okay to mix different viscosity oil like that? If so, about 1 qt of 85-140 sounds good.

Well a fully drained B13/14 tranny will take 4 bottles of gear oil. Just take the averages of the 4 and you will have 77.5W-102.5 or go 50/50 and have 80W-115. The oils mix fine. It just changes the viscosity. Syn. and conventional will blend too.

yes you can mix viscosity oils like that.

I used full 85w140 down into the upper 30's and it was fine. Like he said when you first start the car up and then let the clutch out its soo thick it will actually bog down the engine and actually try to lurch the car forward. Granted it wont actually start going but it will bog the engine down as if you were in a gear letting the clutch out.

Let it warm up idling for about a minute or two then literally about a block of driving its warmed up enough to where its fine. Doesnt take long.

However below freezing i would say use 3 quarts 75w90 and 1 qt 85w140. You could probably get away with a half and half mixture but its up to you.

Thanks guys. I think I'll try 75% 75w-90 and 25% 85w-140.

85w 140 might not work well if you are starting up with the engine cold soaked regularly.

With 75w- 90 I could feel my clutch/shifter get boggy and slushy on startups near or below freezing. I mean I usually give it 30 seconds and just take it really easy for 15-20 min. but I do run oil based in large part based on startup conditions.

You could get a block heater and using that will get the oil hot a lot quicker. Still would run 75w-90 at least half like Ashton said... if it was me.

Plus you can always put 1-2 quarts of 85w 140 in the Spring when it will help you. Gear oil isn't exactly expensive.

Well, with the stronger clutch/pp going in, I wanted something to help protect the gearbox a little. I was going to use Redline shockproof, but everyone seems to be getting good results from the 85w-140. So I figured I would give it a try.

I'm going to mix the 85w-140 in at about 25% for winter though.