Red Line MTF and ATF suitable for long drain interval?

[SOHCman]

I keep reading motor oil threads where red line motor oil is not able to run "long" drain intervals based on UOA evidence. Something about the esters oxidizing maybe?

I have been a fan of Redlines MT-90 and MTF for a good while, and never considered a UOA because I figured it was one of the best protecting fluids I could use in manual trans and transfercase applications.

Are long drains appropriate, or is it a similar situation of their motor oils? Thank you.

 

[slacktide_bitog]

It will probably be fine for long drains since the RL is better than whatever it's replacing, and most cars never get a transmission fluid change and arrive at the junkyard on their factory fill.

Even before they had so-called "lifetime fill" few people ever changed ATF anyway.

 

[JHZR2]

Ive never been a fan of their mtf or differential lubes. In my old bmw, these fluids would get noisy and notchy faster than others.

I found specialty formulations gear oil, and Amsoil mtf to be the best.

 

[SOHCman]

I found an old thread where molikule said the RL MTL is good for 25k, and the same for Hondas MTF. So I would take that as suitable for normal drain intervols, and nothing beyond standard fluids.

MTLs not being exposed to the blow-by and fuel dillution of an engine oil, I guess it's apples to oranges to compare it to motor oil.

 

[Graham Piccinini]

What is your definition of long OCI? Redline themselves said multiple times that their oils are good for 12k OCI. I run 5K oci at most, so for me 12K is a REALLY long OCI, as it is more than double the length if MY longest OCI.

As far as MT90, I run that in my Honda CR-V, and shifting is tons better as compared to Honda MTF, Pennzoil Synchromesh, and Pennzoil Synchromesh & Lucas Transfix stuff frankenbrew. Plan to run MT90 for no longer than 15k miles.

 

[SOHCman]

What is your definition of long OCI? Redline themselves said multiple times that their oils are good for 12k OCI. I run 5K oci at most, so for me 12K is a REALLY long OCI, as it is more than double the length if MY longest OCI.

As far as MT90, I run that in my Honda CR-V, and shifting is tons better as compared to Honda MTF, Pennzoil Synchromesh, and Pennzoil Synchromesh & Lucas Transfix stuff frankenbrew. Plan to run MT90 for no longer than 15k miles.

Interesting, have you done any UOAs on those 5K runs? Engine oil wise, I would personally consider 5K standard, and 7.5, 10, and 15K extended DEPENDING on engine type, oil, temperature, and severity of service. On a CR-V with K24 engine I would consider following the maintenance minder to around 10K with a quality syn completely normal with standard easy highway mix driving.

I have ran MT-90 and MTL in Toyota, Ford and Honda manual transmissions with great shift feel, and usually change when the shift feel gets worse. I just wanted to make sure I wasn't running it too long just because I presumed a group IV/V Syn was suitable for extended manual transmission use. Driving in death valley, serious off-roading or regularly towing at the weight limit might warrant changing more often.

 

[bunnspecial]

As far as MT90, I run that in my Honda CR-V, and shifting is tons better as compared to Honda MTF, Pennzoil Synchromesh, and Pennzoil Synchromesh & Lucas Transfix stuff frankenbrew. Plan to run MT90 for no longer than 15k miles.

I've always thought the "90" in MT90 indicates it behaves sort of like a 90wt gear oil(which should be similar to a 30wt engine oil). When I've used it, it certainly came across as very thick and syrupy. When I've handled Synchromesh in the past, it always felt m e to me like ATF or other lightweight oil.

Could the improved shifting be because the transmission just likes a heavier oil than is specced?

For me, BTW, I had MT90 in a transmission at one point in the past. I didn't see enough of a difference to justify bothering with it, so when I had to drain it(replacing the transmission-not because of failure in the gears/synchros but other reasons) I just went back to using cheap 20W-50 engine oil, which is all this particular transmission ever said to use. That transmission has been replaced again for one with electric overdrive, and again it's full of 20W-50. I'm scared to try anything else with the overdrive.

 

[Graham Piccinini]

Interesting, have you done any UOAs on those 5K runs? Engine oil wise, I would personally consider 5K standard, and 7.5, 10, and 15K extended DEPENDING on engine type, oil, temperature, and severity of service. On a CR-V with K24 engine I would consider following the maintenance minder to around 10K with a quality syn completely normal with standard easy highway mix driving.

I have ran MT-90 and MTL in Toyota, Ford and Honda manual transmissions with great shift feel, and usually change when the shift feel gets worse. I just wanted to make sure I wasn't running it too long just because I presumed a group IV/V Syn was suitable for extended manual transmission use. Driving in death valley, serious off-roading or regularly towing at the weight limit might warrant changing more often.

It's been a while since I've done a UOA. But when I did - at 5k the oil had plenty of life left, but I personally didn't feel the need to stretch the OCI any further. I mostly do UOAs to look for potential hidden issues (small coolant leak, or abnormal metal wear), rather than using the UOA to extend my OCI.

My Honda spec's RedLine MTL, but being in NC, plus on upsized All Terrain tires, and hitting the fields and trails often for fun - I felt that MT90 is a better option. No regrets with that decision. I do wish to try Royal Purple Synchromax, as that has been praised by some in the rallycross community.