Little Trucks, Big World

Lubrication for Transmission Rebuild....GL5 or ATF...

Here's one I was presented with today. I decided to let a professional Transmission house rebuild my FS5W71B 5 speed transmission. They suggested to fill it with ATF, after the rebuild, being as it is very cold up here in Quebec city, and Martin the owner of the company claims that using ATF in the manual transmission rebuilds he does, is working out much better than standard oil. The issue he claims is with lubrication and the cold, the ATF he says works much better, and his customers are very happy as he has had no returns. He says on cold days, that the GL4, and GL5 is too thick, and the bearings & other parts, starve for lubrication, which is causing bearing failure at an earlier interval. What do you think Tiger Racing? and Datzen Mike, and other Oil specialists? Should I go with the ATF? or stay put with the GL4 - GL5 ?  Id' like your input on this...DAttsun Al, 

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Ooooops, I forgot to add, we did verify I have a FS5W71B, with 62mm bearing on the counter shaft, and I am paying more attention to the information provided about always using 4th gear on long hills. 

Sorry if its was already mentioned i just made a post about this in another thread but i think is worth reposting because is good info.There is a Technical Service Bulletin from Nissan advising not to use GL-5 on older manual transmissions because the sulfur and phosphor content can corrode "Yellow Metals" like brass and bronze.This is a very well known fact among the 240sx,Sentras,200sx and many other Nissans with transmissions that have bronze Synchros.Since many 720 share similar transmissions as those found in 200sx i guess is not recommendable for your trucks neither. 

I used in my 240sx and my 200sx Redline MT90 which  is GL4 is phosphor and sulfur content is very low and you will notice  a difference in shifting.There are some other good brands like Amsoil that also meet this criteria.GL-4 Is not easy to find at local stores, only race stores and some napas have it and it usually expensive, Redline is  $11 per quart same as Amsoil  but to me is every penny worth it

Also want to add this is not a myth here is my own story.Me a and few of my Nissan friends  decided one day to meet up and work on our cars changing fluids and tunning up our cars.I told them about we all buy in same store to get a discount but 4 of them  refused due to high cost of GL4, those 4  went and bought  GL5 at local auto parts.I insisted but none listened, 3-4 months down the road first transmission broke, few weeks after that on the way to the track another, about 1 month later another one.Common factor? GL5 in all of them, the last guy decided to flush and add GL4 but damage was already done it lasted like  1 more month.

Just wanted to share this info with you guys,This are tough times and I know how expensive repairs can be .By the way I'm not advertising anything at the end you do whatever you want to, I'm just a Nissan freak owned like 8 of them so far from 1980 200sx Z20E to a 400whp 240sx/sr20det and anything in between.

Thanks for the post Allan. I don't understand why anyone would put GL5, made for the Transfer case and Differential. in the Transmission, when Nissan CLEARLY STATES,  GL4 only. The guy who rebuilt my transmission had to take it back out to fix a leak from the front gasket not done right. But after putting it back in Fresh GL4 went in, and man, it shifts like warm butter, so smooth, excellent. 

No Problem but trust me i have seen people done all kind of things to save a few bucks just to end up spending hundreds on repairs.There are some GL-5 fluids made for manual transmissions but should not be used on transmissions with yellow metals. Most of Castrol,Coastal,Penzoil and many others are GL5 made for manual transmissions.Swepco famous among the Porsche is GL5 also MT-1 but to be honest i don't know or trust the MT-1and   i have been using Redline for about 12 years with great results specially when you flush and put new fluid in you will notice more more smooth shifting.But also heard the same from Amsoil users so to each its own there are some online stores where you can find Redline and or Amsoil for $10.

Just an update... I have driven my truck over a year with ATF in the 5 speed transmission. It was just rebuilt last year when I started this. I have driven over 30 thousand miles in the truck with no problems at all with the transmission. No leaks, no shifting issues. Nothing so far. I will update you next year or sooner if problems occur. I will be changing the ATF this week and will report any problems then also.

Changing over to ATF is becoming more popular.. i dont have the balls yet to try it.

 Racers are running it in their diffs now too

Yep, I feel the same way, my truck is used for long trips, back and forth to USA, and Quebec city, from Montreal, racking up a lot of miles. The last thing I need is to find out on a long trip, that I have caused some sort of damage to internal parts in my transmission. I do hear what you guys are saying about the ATF, but...I know many folks right at this moment...that are shelling out bucks to have their Automatic trans rebuilt. The last one I did on my F350, and I had 2 of those, the 1996 had to be rebuilt, and the 2002 had to be rebuilt. ATF is a Hydraulic/lubrication oil meant to work in a different manner than GL-4 or 5, designed for older 5 speed trans like in the Datsun. My experience as a Tool & Die maker, and in the manufacturing industry makes me feel, that I had better stick with what the Engineers specified for the application. Also, I do not have a "spare" transmission, or vehicle. So for me, its what the engineers say I will use. Happy Motoring !!! BTW, since moving back to Canada, I have had 4 people try to buy my 84 King Cab...and my answer...FORGET ABOUT IT...!!! NOT FOR SALE !!! 

I completely understand... I just love to mess around and experiment... I should point out that I use the truck to travel all over the country as well. 1 trip form Atlanta to NY and back, 18 hours one way. 1 Trip to West Virginia and back to Atl. 11 hours one way. 8 trips to New Symrna Beach Florida, 9 hours one way. All with ATF in the Transmission, plus local driving every day. So far, there have been absolutely no problems with the transmission. Having said that... The thing could explode tomorrow... lol I will report any problems or occurrences honestly so at least you can judge the results of my little experiment.

Atf is used in racing application because is thinner and it works but i rather use what is intended for that particular tranny.It's a well known fact that gl5 eat bronze synchros in some Datsun/Nissan transmission ask any sentra 200sx and 240sx owner who have used GL5.

I've been using Redline for a long time as  amatter of fact I switched to Redline in our 1980 200sx that has about 400k miles we are the second owners but previous owner was a family member so we know all about the car and that transmission has never been repaired not once.Engine was rebuild once at around 300k and we live in a hot climate all year long and most of those miles are stop and go traffic .

Also some transmissions are designed to operate more effectively using a particular fluid thickness so premature wear can happen if you decided to use a different thickness.

I'm not telling you what to use or what not I'm just sharing my own experience with lots of different cars many of them Datsuns and Nissans since is or more likely was my favorite make.

And that is just fine, I think it is good that we have an "experiment" but for me, I will stick to the recommendations. I am sure the ATF will hold up for some time, but I think in the long run, there may be issues. Its just my view, and I am more in agreement with Allen, who posted about the GL5, and ATF in racing, and also about the Redline. I have heard good things about Redline and may have it put in this year. In any event...keep posting and keep us informed Scott Felsen, inquiting minds want to know. DattsunAl. 

again... some here use ATF, I use normal gear oil, and some follow the rules....

Lets find out who has had failed transmissions and what oil they used.

 My tranny has well over 200k on it, and is like brand new.


How has the ATF switch gone after all these years?  Would love to get an update, as you mentioned!





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