What viscosity should I use for my manual tranny?

[JohnSaints]

Hi there,

I wish to do a transmission fluid change next weekend.

I have a JB3 Renault Transmission that holds 3,4 liters of fluid.

The car manual does not spec viscosity, only the GL5 norm.

Factory viscosity and viscosity used by the brand in this tranny is 75w80.

My question is if I should use 75w80 or if I'd have any advantage in using a different thickness like 75w90 or 80w90.

I notice that the gears have a harder time going in in cold weather and when the car is not up to temperature (especially 1st and 2nd gears).

The car is 15 years old, so is the transmission.

 

[bmwtechguy]

Can you find some original equipment manual transmission fluid/oil from a car dealer? They are expensive usually, but shift the best as the fluid has the correct friction for much better synchronizer operation. A full synthetic fluid would do better in cold weather. I would not use a GL5 fluid. I have used a couple of aftermarket synthetic fluids here in the US, Redline MTF and Amsoil MTF. Either fluid would probably work well in your application for a reasonable price. Just make sure that whatever you buy is made for Manual transmission/gearbox use, and if you want easier cold shifts, then stick with a full synthetic and/or a lighter oil like a 75W-80 vs a 75W-90. Perhaps a heavier 75W-90 GL-4 manual gearbox oil would be better for a high mileage gearbox.

 

[TallPaul]

I have Redline MTL in my Ford Ranger and my Son's Chevy S10. Good stuff. Redline also has other grades of manual tranny fluid. Make the refill easy, get a clear plastic tube (the right diameter to fit snug in the filler hole helps). Run the tube up into the engine bay and use a funnel to pour. Have someone under the vehicle watching the fill end of the hose. A lot easier than trying to pour it in from below.

 

[oggb]

If it needs GL5 fluid and it specs 75w-80 I'd use whatever 75w-90 or 80w-90 GL5 gear oil you can find that is a brand you trust. Valvoline 80w-90 gets my vote.

 

[bmwtechguy]

I pulled up the Liqui-moly website there in Portugal and found up to 5 different manual gearbox oils to choose from on pages 46 and 47 of their online catalog. They are listed as Getriebeoel. Not sure how much luck you would have finding one of their products in a store there. One of the MTF's is a synthetic 75W-80, but for an older car, I think a 75W-90 would be just fine.

But, unless your gearbox has a hypoid gearset in it, then there is no real need for GL-5 level of EP additives. A GL-4 lube would be plenty. If you do use a GL-5 rated lube, just make sure it is intended to be used in a manual gearbox with synchronizers. If it is GL-5 gear oil intended for limited slip differential hypoid gearset, then it will have the wrong additives (too slippery) for synchronizers, and you will have a more difficult time getting it to shift smoothly. Been there, done that years ago.

 

[mechtech2]

Like BMW said, the first thing is to determine if the transaxle has a hypoid gear in it, or helical.
[Is there a 90 deg change in power flow? - It is then a hypoid gear]
This almost always requires a GL5 fluid.
See what Amsoil has to offer . A full synthetic fluid is best, esp for cold weather.
Contact Pablo on this site.

 

[Rollins]

I think you’d better stick to what the OEM recommends- that is

Tranself TRJ 75w-80,
http://www.lubadmin.com/upload/produit/FichePDF/lang_5/1075.pdf

now superseded by Tranself NFJ 75w-80
http://www.totaloil.com.au/Pages/content/NT0000C9DA.pdf

Just like Peugeot/Citroen transmission fluids(made by Exxon-Mobil and Total), Renault tranny oils are referred to as API GL4+ fluids in the PDSheets but often GL-5 is written on the label.
And I believe there is a reason why Renault recommends a specific product of ELF’s 75w-80 fluids for each of their gearbox families, which can be seen here:

 

[mechtech2]

How could they recommend fluids that did not exists then?

The factory recommendations are a guide, but better products are now available.

 

[JohnSaints]

OP here.

Thank you guys so much for all the helpful tips.

It's very hard for me to find what I'm looking for: a 75w80 synthetic GL4+ oil.

Heck, I'm even having trouble finding any 75w80 gl4+ without havin to order it online from abroad or pay big, big bucks.

I can, though, very easily find GL5 75W90 oil in a garage near me for a decent price.

I can also get a 75W80 GL5 and 75W90 GL4+ online or the factory 75w80 gl4+ from online abroad (but I'd have to spend close to 75 dollars to get it).

What do you guys think of my options?

 

[mechtech2]

The local GL5 75-90 may be OK, but it is not a specific manual trans lube. It is second or third choice.

 

[dwcopple]

10w40

 

[Rollins]

Hmm…

You can find Peugeot/Citroen GL-4+ SAE 75w-80 oil cheapest at the dealer (it is actually Esso Gear oil BV 75w-80 …now called Mobil Gear oil BV packed in a grayish PSA bottle). Was roughly 10euro last year/1 liter bottle.

You can probably find Fuchs Titan Syntofluid 75w-80…

…or Valvoline RPC 75w-80 (recommended for Renault and PSA boxes…been using its predecessor Valvoline HP PC 75w-80 in an old pug with no ill effects for years…)

…or Texaco Multigear RN Premium 75w-80

…I’ve used Shell SF 5288 75w-80 in the past too…new name is Shell Sirax S4 G 75w-80…


I haven’t tried SAE xw-90 in my pugs’ trannies myself but have heard complaints about hard shifting at low ambient temps. Here you can graph some oils for comparison:
http://www.widman.biz/English/Calculators/Graph.html

I find 75w-90 too thick for this application. Your fuel economy will suffer too. The question about improper shifting due to different friction characteristics of the non-OEM specified oils (be they 75w-80 or not) still remains…

 

[jdawg89]

The easyest way I've ever seen a tranny fill up was through the top! Right through the shifter hole. And you wanna hear coldd weather nightmares with standards? 1962 chevy k20 with a 4 spd... it won't idle in neutral with the clutch out. You have to warm it up with the clutch in even in neutral when its cold. That's thick oil lol

 

[Zaedock]

Originally Posted By: jdawg89
The easyest way I've ever seen a tranny fill up was through the top! Right through the shifter hole. And you wanna hear coldd weather nightmares with standards? 1962 chevy k20 with a 4 spd... it won't idle in neutral with the clutch out. You have to warm it up with the clutch in even in neutral when its cold. That's thick oil lol


I run the same tranny in my Jeep. 75W90 works mint in the cold.

 

[4wheels]

Total/Elf TRJ trans fluid is very good stuff. Strong add pack to prevent wear & one of the lower viscosity "real" MTF's. If your car needs this or used something similar to this from the factory I wouldn't switch to a thicker gear oil. It is available from several shops in the USA who cater to imports. Here's a link I just found to a shop selling it ridiculously cheap (about $5 per liter).

http://performanceoilstore.com/products.asp?id=3

 

[jdawg89]

I'm not too concerend with it at the moment...I have absolutly no idea what's in there for lube if if there's any in there..lol its just the old beater plow truck. Won't go into reverse hardly at all any more...takes a lot to get it in lol. Anyways I've got a new tranny for it...just gotta put er in lol