Changing out my MISTAKE gear ol choice...

[Jaymus]

Need some help on my next decision. I went on a 75W-90 Mobil1 Gear Oil spree in my 86 F-150 with 4 speed NP435 and another 01 Eclipse GS with a 5-speed.

The 5-speed started acting up. Yeah, I later learned about the Group IV vs V gear oils. Should have went with a group IV. I may be using the wrong word, am wore out, but you guys know what I mean.

We put some of the earlier model (Group IV?) Redline MT-90 and it took away her grinding. My NP435 did fine with the new spec (wrong kind) for longer than her car. Now... I'm feeling the synchro roughness. I know it's not too late. Her's is back to normal. Better than ever.

Do you guys recommend Redline MT-90 (75W-90 synthetic on the thick side of the 90 weight) for my NP435? Probably will be ordering it tomorrow.

 

[hate2work]

Redline makes very good gear oil, as does Amsoil and Schaeffers.

Some of the old Fords used 10W-40 motor oil in the manual transmission.

 

[Jaymus]

Right, thanks for that tip, but in my book, it calls for an 80W-90, so I think I will go with the Redline MT-90. Thanks. BTW, the Redline MTL (90w) is thinner than the MT-90 version. I think I'll take that little extra viscosity.

BTW, my gas mileage improved tremendously when I went to the synthetic M1 75W-90, so I am definitely sticking with synthetic in my NP435.

 

[Jaymus]

Bump: Does anyone know of any local stores that stock this Redline stuff? I don't mind ordering online... I just want it fast. Like.. Napa, or just any odd little places I should check? Redline MT-90 only.

 

[MolaKule]

See this thread:

https://bobistheoilguy.com/forums/threads/synchromesh-manual-transmission-lubricants.93561/

post #1231225

 

[Jaymus]

Yeah, I was saying Group, meant GL4 and 5. Just wondering where I can get the GL4 Redline Synthetic (MT-90) in stores?

 

[mechtech2]

The REdline is far superior in a manual trans than gear oil.
It is a dedicated sauce made for good shifting and great wear characteristics.
Whether or not a fluid is simply GL4 or GL5 is not the key.

 

[Jaymus]

It is part of the key. GL5 in old transmissions = a no no.

 

[wantin150]

PM me for a link to an on-line site. I just got some from them and it only took about 5 or 6 days (not too bad). I forget what I paid, probably $8.50 a qt.

 

[aquariuscsm]

You can also always try Amsoil MTG or Royal Purple Max Gear. O`Reilly`s and NAPA carries Max Gear.

 

[mechtech2]

Jaymus - Actually you got it backwards - OLD Gl5 is the no no - not the trans.
It is unbuffered and can be harmful to brass synchros and parts.

 

[artificialist]

Local speed parts shops typically carry Redline, but sometimes they don't.

 

[Serpent2002]

What do they say about group IV and Group V gear oil in old transmissions? Can you enlighten me? I am about to change the gear oil in my friend's 1989 toyota 4WD corolla wagon (manual, 1 center dif and 1 rear diff.). I was going to push him in the direction of a synth gear oil after an auto-rx cleaning of his trans, but I would definetly like to hear what this information is. The search function sucks, I'd be so grateful if I could get a recap.

Thanks!!

 

[Jaymus]

I was saying group IV and V, but I had the real term on the tip of my tongue. GL4 and GL5.

You'll have to check the manual for what gear oil the transmission uses. Some may use an engine oil, but others may call for a GL4 80W-90, which is where you can use a GL4 synthetic like Redline MT90 (75W-90).

 

[aquariuscsm]

Originally Posted By: Jaymus
I was saying group IV and V, but I had the real term on the tip of my tongue. GL4 and GL5.

You'll have to check the manual for what gear oil the transmission uses. Some may use an engine oil, but others may call for a GL4 80W-90, which is where you can use a GL4 synthetic like Redline MT90 (75W-90).


Yep,definitely check the owners manual or fsm. Manual transmissions take anything from atf,to motor oil,to gear oil. Different makes of manual transmissions all take different lubricants.

 

[Jaymus]

Yeah, it's odd how a Dodge with an NP435 transmission (70's) called for motor oil while a Ford with an NP435 called for gear oil. 10W-40 vs 80W-90 (which I know both are about the same weight).