i no its been talked about alot but cant find the thread any one any ideas or have a link to the thread/s.... just wanna keep things runnin well . thanks

 

there are a few choices...this was recommended to me and it worked fantastic

transmission- redline mt-90 75w90

differential- redline lightweight shockproof gear oil

i believe this is what i used. it was 2 years ago and i cant remember if i used heavyweight on the diff or lightweight. someone will correct me if im wrong..

 

i run neo synthetic gear oil HD 75-90

this stuff works magic

i've heard of too many people having problems with redline

 

its nearly the same as redline...what kind of problems are you speaking of? its the same weight but the redline is specifically for synco longevity. it was like a rebuild for me after i changed out mine; i can say nothing but good things about it

and you should prob specify the oil you sudgested is for his transmission. that way there's no confusion

 

The NEO 75-90 HD/RHD is for both your transmission and your diff. They sell it in one gallon jugs and it's *just* enough to flush/replace both your diff and your tranny. I did this about a month or two ago, MUCH better since then..

 

i used 20-50w valvoline vr1 engine oil. in my tranny i know your like wtf but believe me i didn't belieev it either till i used it . a very reputable fd and rotary shop here in s. florida has been using it for nearly 15 years and everything has held up and lasted longer than said gear oils. and when i say reputble rotary shop i mean home of the 3 rotor special build fd's that people were buying for upwards of 50 grand hint hint.

 

i think dave will have something to say about this...

how so? diff gear oil is usually a higher weight like 80w135. isnt it? and theres no way 1 gallon fills your gearbox and the diff. im sure of it

 

I changed to royal purple synthetic last week. I don't know what fluid I replaced but a noticeable difference with the royal purple. I bought it at Napa and used the 75/90 wt.

 

Redline Mt90 in the trans
Redline 75/90 in the diff fore me

 

With all due respect, I'll bet you can't tell whether it's working or not.

Gear oils used in synchromesh transmissions have 3 major jobs:
- reduce friction and wear on bearings
- reduce friction and wear on gear teeth
- reduce wear and support synchronizer function.

Unless you tear down the gearbox or do trending oil analysis, you won't know about the first two.

The synchros usually don't perform best in the gear oils that are designed to maximize bearing and gear performance, so synchro gearbox oils are a compromise. Given that transmissions are splash lubed and take a while to warm up, I firmly believe that mineral oils have no place in a performance car transmission.

Motor oil might well make the tranny shift beautifully, but using motor oil will cause accelerated wear, increased friction, and reduced shock strength. I happen to believe the best oil for our trannys is a synthetic GL-4 or GL-5 in 75-w90 or similar. Redline MT-90 and Amsoil MTG are perfect matches, with Royal Purple, Neo, and a few others making very similar products.

I also believe the diff is a different beast. It has no synchros and it has the highest gear loads in the vehicle. As a result you should be using the highest performance gear lube that's practical. In other words, something different than what's in the gearbox. If you read labels you'll find gear lubes that are for differentials and not for synchro gearboxes - this is the kind of oil to look at for the diff.

The cost is small, and the benefits include higher drivetrain capacity and lower friction (more power). I think it's a no-brainer.

 

thanks for the replys lads .guess im off to ebay to price them up.cheers

 

Screw ebay. Support your local racing shop.

Shipping on fluids is pretty outrageous, so it'll be the same or cheaper, plus you get to meet real human beings.

I've got Valvoline SynPower 75w-90 in my trans and diff. I don't like it in the trans and will probably change it out for some boutique lube like NEO. Shifting suck until the Valvoline gets some heat in it. I don't think it works as well as it could with our synchros. Maybe it's just my car...

 

I've got pennzoil synchromesh in tranny and it's smooth like butter.

 

+1

 

You've got to remember you live in a relative paradise to everyone else on this board. If it was 70 deg and sunny every day here mine would shift well when it first started up too. I was just out there visiting a friend.

VA weather is bi-polar as hell.

 

It's not just your car. I tried the Valvoline Synpower 75W90 also, and it was worse for synchro action (1st-to-2nd shift most noticeable) when the trans was cold (below 50F) than the OE dinosaur fluid, which was not too bad. I then changed to the NEO 75W90, and it is now significantly better than either the OE or the Synpower under the same conditions.

 

Good to know, I'll try the NEO when I get a chance. I think I'll leave it in the rear end, though.

It's the exact same story with me: 1st to 2nd sucks until it's warm with SynPower 75w90. At least we've got some info on what oil NOT to use in the trans.