For all competition work I've always used ATF and found it to be kind to the synchros and with very low drag, allowing fast smooth changes even with marginal synchro quality.

hugh

By Tracy (Rx7speed) (152.163.100.199) on Wednesday, April 20, 2005 - 01:34 pm:

well aware jarcaf but one of the first post I made here said notto use 75w-90 (since I have some sitting in my garage from my mazda that I didn't have a chance to put in) or any real gear oil in the transmission and rather to use 10w-40. being I'm not a fan at least in the motor so figured 5w-30

but why would my results be so different with synthetic then what everone said I should have?

and would 5w-20 cause any damage to the tranny though if I was to use it?

By Jarcaf (Jarcaf) (66.241.66.51) on Wednesday, April 20, 2005 - 01:03 pm:

So are you running motor oil or gear oil in your tranny? I know mobil makes a 75W-90 synthetic gear oil.

By Zippy (Zippy) (12.106.14.107) on Wednesday, April 20, 2005 - 06:55 am:

Back when Zippy was running I put a 5w-30 synthetic in the tranny and was pleased with the synchro preformance. I actually found it much easier to down shift without using the clutch. I like to left-foot brake in autocross and prefer to ignore the clutch as much as possible. Having one foot on the brake an one on the gas and having a reliable no clutch shift allowed me to get the best out of the car. I can shift the weight around really fast.

Of course, I have never been inside a transmission and only have a picture book understanding of the synchro mechanism. Zippy only got 1 light season with that oil in the tranny. I can't comment on the long term wear.

By Tracy (Rx7speed) (172.149.142.158) on Tuesday, April 19, 2005 - 08:30 pm:

I don't see why some people where saying don't use synthetic motor oil in your transmission. I made the switch to 5w-30 mobil 1 today and it seems to run a little smoother when driving but the main thing I noticed is the complete opposite of what others where saying. before going into 5th gear would be a little tough and shifting into 1st would almost always grind at anything other then the car sitting still. after the swap I was able to shift all the gears including first and fifth without any effort or grinding.


all in all seems like the synthetic is doin al ot better of a job then the normal 10w-40 castrol that was in there before.
so all in all what gives? why so different then whatI was hearing before as to what to use?


another question could using 5w-20 or 0w-20 full synthetic mobil 1 cause any harm or should I just stick with the 5w-30?

and as far as the type of mobil 1 one last question
I just grabbed the weight I was looking for in full syn. but later noticed it was the extended use oil so I'm assuming it just has a heavier addative package. should I have just gotten the normal mobil 1 synthetic. do you think it would of made any difference on gas mileage?