Temps and Manual Tranny Operation with Different Fluids....

[Idrinkmotoroil]

In my quest to improve the operation of my manual transmission I've arrived at some conclusions about temps and fluids I've used. Firstly I have a 2004 Dodge SRT-4 which uses ATF+4 with 4 oz of Mopar Friction Modifier as stock fluid in a 5 speed manual transmission with Quife ATB limited slip differential in a fwd transmission configuration. The stock fluid plain sucked at any temperature, and it had a short lifespan.

In using Royal Purple Synchromax MTL it has a viscosity similar to an ATF - around 7.7 cst. While it is good when cold, shift quality deteriorates as it heats up. I've also used Redline MTL, it is okay when cold, but really shifts well once it has some heat in it, the more heat the better it seems to shift. I believe it has a viscosity in the 10 cst range , give or take.

My next fluid will likely be one of the Specialty Fluids products.

Judging by this testing is there anything we can deduce with regards to viscosity and shift quality. I think the transmission likes a bit more viscosity despite being developed for an ATF fluid. I think any transmission is notchy when cold, but this one seems to like a bit more viscosity when fully warmed up. I'm tempted to try some Redline MT-90 in the mix but haven't been able to experiment with it yet, not too sure how it may work when cold either.

Any advice on my findings would be appreciated, in terms of viscosity recommendation. thanks

 

[Whimsey]

I've noticed the exact same thing with my truck's manual transmission. It's spec'd for Mercon ATF. It shifted better when it was very cold outside. Once the temps got even into the low 30's the shifting turned terrible. It crunched and clunked. I swapped to Scaheffer's 204S Mercon/DexronIII semi-synthetic ATF and it helped but once it got warmer outside it still shifted poorly. Although it was a lot better than the Factory Mercon ATF. In speaking with MolaKule we decided to use his SynchroGlide. It's a Group IV and Group V manual transmission fluid. It's more viscous than ATF, 9.5 cST vs 7-7.5 cST for ATF plus it won't thin out when it gets hot. So far the shifting has been 1000% better

. It even shifted great in the teen temps we had after I installed the SynchroGlide. We've had temps in the low 50's and the shifting with the SynchroGlide was sooooo much better than the Mercon or even Schaeffer's ATF. I'm sold on SF's products. Anything that can make that crappy transmission shift a lot better derserves

.

Whimsey

 

[Idrinkmotoroil]

thanks for sharing the great info, I hope to get some SF fluids in the transmission soon. Despite specifying an ATF fluid I also want something that approaches 10.0 cst viscosity. I'll be hitting mola up for some of that fluid shortly. thanks for the info.

BTW the transmission they put in my srt-4 was designed for their truck division, it is a T-850 New Venture transmission. It is able to handle the torque of the turbo engine but it shifts like a delivery truck.

 

[mechtech]

I'm not sure the trans was designed for ATF, but rather was spec'd to be OK with it.
I don't think the trans engineers said ATF was the best possible performing fluid - it was either retro'd or worked around on design because they were told to use it.

 

[Idrinkmotoroil]

quote:

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Originally posted by mechtech:
I'm not sure the trans was designed for ATF, but rather was spec'd to be OK with it.
I don't think the trans engineers said ATF was the best possible performing fluid - it was either retro'd or worked around on design because they were told to use it.

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I truly believe that, I think the transmission has been used in Europe and N. America on commercial trucks. I doubt they would use a thin ATF on a commercial truck application. I believe the engineeers were told to make it work with an ATF like you stated, when the transmission was put into a passenger automobile to avoid cold weather shifting complaints if it was to use a regular gear oil. They also spec'd 4 oz of Mopar Friction modifier to be used with the ATF which leads me to believe that they had reliability concerns by just using straight ATF like is used on the lower based Neon T-350 transmissions. Friction modifier is usually spec'd with certain limited slips , but the Quaife ATB limited slip on my car doesn't use any clutches and there are no chattering issues with this type of lsd. All I can deduce is that they wanted the FM to add a bit more protection to the thin fluid as it is severely hydrocracked.

 

[ripcuda]

idrink...,

Have you tried the Specialty Formulations product yet in our SRT-4 transmission? Aren't you now using Amzoil MTF?

I see you're battling hard over on the SRT Forums to explain to the masses why MTL is better than the stock ATF. Plus the whole FM issue.

I too have tried a few different fluids.
Stock sucked. Then I ran straight Pennzoil Synchromesh (no FM) for about a year... it was a huge improvement. Great balance of cold (lived in CO then) and hot shifting.
Then this last March I changed to straight Redline MTL (no FM). It was as good or better than Synchromesh when hot, very smooth... but not as good when cold. Annoyingly worse enough that I drained some and added some Pennzoil Synchromesh again. I now have 1/3 MTL, 2/3 Synchromesh and it has been a good blend over this past summer.

It's now getting cold here in Alabama... and I'm noticing less than stellar cold shifting... mostly my annoying 2nd gear. Warm/hot is still great. So I'm thinking of going back to straight Synchromesh again.

So any news about Amzoil MTF or SF fluids would be great! Thanks for the good info.

 

[bulwnkl]

I have the 'lower' T350 in our 2000 Neon. According to the part number on the transmission's metal tag, it is one of the revised, higher-torque, ATF+4-spec'd transmissions they switched to in the late winter/early spring of 2000.

I have never had ATF+4 in it. I drained the stock MS-9417 fluid out when we bought it at ~35,000 miles and put in Redline MTL. It was just amazing for shift quality that summer. However, I drained half and added a qt. of MT-90 to try to quiet a slight whine. Summer shifting was still great, but I presently wish I had straight MTL back. This winter I've noticed sluggishness in the shifter on cold mornings, but recently I've decided this is linkage stiffness rather than transmission sluggishness. Mainly because of how few miles it takes to be gone (I don't think the transmission fluid warms up that quickly), and because of how well/smoothly/quickly it actually goes into gear (rather than just moving the shifter around).

I'd like to try some ATF+4-viscosity fluid to see whether I get better economy, but I don't want to give up MTL's superb shiftability. The SF product I have in my Subaru is terrific, but the budget precludes experimentation in this car with fluid that expensive.

Idrinkmotoroil, did you see a mpg change when you changed between ATF+4 and Redline MTL?

Thanks!

 

[kendogg441]

Whimsey - What Ford Product do you drive? I'm buyin a 97 Ranger with the 5 sped, which calls for ATF. How cold does it get in your area? It gets down into the negative temps here, but I do warm my vehicle up first in the morning for 5 or 10 minutes. Do you like how the SF Synchroglide feels at extremely cold temps? How does that compare to Redline MTL or Synchromesh?