Well with the cold weather and increased difficulty getting into gear quickly, I decided to put the redline oil I bought a few months ago in my daily driver RX. I did 75W90ns for the transmission and 75w90 for the LSD. The results are in...

 

It is probably the best 'mod' I have done to this RX so far. It feels like driving a brand new car! I have this in my other RX, but since I only drove it during summer months and never that often, I never truly appreciated it.

 

At 20 degrees outside and on a cold start, it shifts better than it did when warm on the old oil that was in it. There is virtually no difference between hot and cold, just super quick syncro and butter smooth shifts. Also it might be just me but it seems to pick up speed faster rolling down my sloped driveway (concrete) now when it's cold.

 

I was getting 28 on this car with 50/50 highway-city and babying it, and this last tank I got 25.5 with all city and not keeping out of the boost. I'll see what difference if any this oil makes on the next tank and report back. Anyway I feel comfortable saying this is the best $60 or so I've spent on the car so far.

 

The RX is now 100 times more enjoyable! All I can say is DO IT!

I was using redline in the my vw tranny and it was all fun but now im running Penzoil Syncromesh with even better results.

hmmm, i need to look into this.

I have been recomending Red line fluids for a long time now.

glad to hear somone who agrees.

the MTL might be feel evin smoother than the 75w90.

my wagon has the 75w90 in it and still is stiff cold.

my old RX (junkies) would consistantly grind 2nd gear when I got it. I changed it to MTL and within a week it was shifting smooth.

I saw a lot of recommends for the MTL on nasioc and a few here as well. I almost got it but then decided to get the 75w90ns becuase it was GL-5 instead of GL-4, which is what you are supposed to use in a trans with internal hypoid diff. Conversely, most GL-5 spec'd oils also wear syncros faster, which may be why so many of these cars with high mileage develop shifting problems. I think a GL-4 like MTL would almost certianly provide at least some better shifting quality, but how much so, and at what long term effect on the differential I am not sure.

as always Shadow you have done your homework.

I checked on http://www.redlineoil.com for more info and I agree you have picked the best redline fluid for our transmissions.

good call sir.

I can report a very similar experience with redline 75w90NS in my manual tranny, 88 SPFI, 175k miles.

 

There is no comparison to shifting now than before I put it in. I can actually shift now (especially when cold)!

 

However.... I may have waited too long... I need to double clutch on downshifts otherwise it won't shift that well...

what is a hypoid diff... i never understood that.

Synthetic is nice.

I had similar results when I put AMSOIL 75w90 in my MT and LSD.

what is a hypoid diff... i never understood that.

 

Hypoid is the way modern differential gears are cut. You see that the gears teeth are 'curved' and also that the driving gear (pinion) is located to mesh above or below the center line of the driven (crown wheel) gear.

 

In the olden days, bevel cut gears were used, which you may be familiar with, from cheap lawnmower steering boxes, technic legos, etc. They make contact exactly on thier centerlines at right angles. This means that the driveshaft had to be mounted higher, and the gears are noisier.

 

Hypoids are quieter because of thier nature, they have a sliding, more gradual contact pattern. Thats all well and good, but it makes the contact pressure higher, so a higher pressure rated oil is needed. Regular helical, bevel, and spur cut gears do not need the high pressure, GL-5 rated oils.

how often should you change the oil ? using redline , going to try it in the turbo wagon next oil change

A standard interval would be 60k (30k extreme service), and I would suggest keeping that if the car is subject to any abnormal abuse. Since manual transmissions are not subject to any filtering, and only have a magnet to collect metal particles, a full flush is the only way to really clean the system. Under normal daily operation, I would say 100k would not be a problem. In fact many people probably have run regular dino oil out past 100k in many of these older cars.

what kind of fluid do you reccomend for my '79 DL 3 speed auto tranny?

front diff?(fwd)

where do they sell redline? i am doing a tranny swap this weekend and plan to try it

I don't think schucks or napa had it when I looked a while back. One of the guys at napa said he though a local independent shop carried it, so I called them and ordered some through them.

 

If nothing else I think you can order it from their website.

crap don't have time to order it pulling a one dayer this weekend rented a garage

out with the old and in with the new

Call around, lots of speed shops carry Redline MTL. Be prepared for a bit of sticker shock tho.

can this stuff make much difference in a perfectly running manual trans that doesnt' have any problems and has new synthetic gear oil in it...comments?

 

is this more a function of replacing old oil or a help for poorly shifting transmissions or something that even a perfectly running/shifting trans can gain benefit from? i always drain/fill with synthetics on my manual trans and have never noticed a lick of difference in anything.

gary, whats the weather like where you live because here in colorado on days where it is 20 degrees or less it is very difficult to shift for the first ten to twenty minutes

it's been 10-20 a dozen times or so this fall/winter. single digits is about the bottom around here, rarely gets below 0.

 

hard to shift like it won't come out or go in gear or the shifter won't move at all?

just really stiff going in and out of gears of course this could just have been a sign that my tranny was going

My cars with dino oil in the tranny are always like stirring molasses with a stick when it's -30c out. Switched to a synthetic and it's much better.

Any word on your fuel economy after refilling with the Redline?