transmission fill level

[grey fist]

Slightly different take on a much discussed topic. Has anyone just filled until fluid comes out of the hole and capped it?

Of the 10 cars I've owned in my lifetime, all manuals with side fill plugs, factory spec on all was to fill until it drips. I'm thinking the 20mm/1inch thing might just be another scheme to eke out a bit more mpg and not necessarily best for transmission function or longevity. Why would Getrag not just make the hole 20mm lower? Conversely downsides of overfill could be leaking seals from excess pressure or aerated fluid. Anybody try it?

 

[JDG]

This has been discussed at least 25 times in a dozen different threads. No real need to start a new topic. General consensus is to fill it with two full liters which should get you right to the fill plug as you describe. Good luck.

 

[grey fist]

I read those threads. Not what I asked. Slightly rephrasing, has anyone ignored the whole 1.67 vs 2 liter vs 20mm below the fill hole and just filled until it dripped like you would with any other manual transmission? If so, how did it work out, any issues?

 

[LilPartyBox]

I know what you mean had have used that method on various VWs and Mazdas. But I filled mine with 2 liters and closed it up. No drip. Shifts like butter.

 

[Rocketst]

Until you can feel it with your finger in the inside of the tranny or 2 quarts. That's how I fill it anyway.

Sent from my moto z4 using Tapatalk

 

[grey fist]

Thought I would provide a bit more context on why the question.

My car has only a bit over 6k miles and I've changed the trans fluid 4 times already. Usually do first change on my cars at about 1k to flush any break in metals, then change at 30k intervals. The Fist has ended up being a bit of a science experiment.

First fill was 2 quarts (1.89 liters) Redline recommended MT-LV. Checked level with a piece of bent wire for a dipstick, hard to read but fairly sure I was within 20mm. Not happy with it, worse than factory fill, just felt too thin, worried about health of the transmission changed it after about 2 weeks.

2nd try drained a quart of the MT-LV and replaced it with thicker Redline MTL, 50:50 mix. At suggestion of someone on here this time used a bent zip tie as dipstick, "teeth" on tie keep oil from running off, again verified within 20mm. Function/feel was much better, left it in about 6 months.

3rd try 2 quarts of MTL, perfection is the enemy of good, had to try it. Changed it in the middle of summer and thought I'd found Nirvana, then came cooler fall weather and it felt a bit notchy.

4th try, had the leftover quart of MT-LV from 2nd attempt, zero cost for an additional data point. Drained 1/2 quart of the straight MTL with intent to add 1/2 quart of MT-LV for 75:25 mix, ended up using 3/4 of the MT-LV for total fill of 2.25 quarts (2.1 liters) and ratio of 66:33. Didn't bother checking level but this amount was not enough to run out of the fill hole. Shifting was markedly better, greater than could be explained by fluid mix alone.

Got me thinking, since it's generally acknowledged that factory fluid is too thin, only specced for mpg, is it unreasonable to suspect that they might have done something similar with fill level spec? As I stated in my first post it's been my experience with many different transmissions that fill spec is always to level of the hole. Was this original design intent for the Fist trans as well, but in the interest of reducing fluid friction for mpg a lower level was specced?

 

[haste]

I just use the ford honey in both my FiSTs and find the shifting good all the time. I've been putting in two US quarts per fill.

It seems all this fluid changing and experimenting is crazy. Why not just use a fluid that the transmission was designed to work with.

 

[Ford ST]

Thought I would provide a bit more context on why the question.

My car has only a bit over 6k miles and I've changed the trans fluid 4 times already. Usually do first change on my cars at about 1k to flush any break in metals, then change at 30k intervals. The Fist has ended up being a bit of a science experiment.

First fill was 2 quarts (1.89 liters) Redline recommended MT-LV. Checked level with a piece of bent wire for a dipstick, hard to read but fairly sure I was within 20mm. Not happy with it, worse than factory fill, just felt too thin, worried about health of the transmission changed it after about 2 weeks.

2nd try drained a quart of the MT-LV and replaced it with thicker Redline MTL, 50:50 mix. At suggestion of someone on here this time used a bent zip tie as dipstick, "teeth" on tie keep oil from running off, again verified within 20mm. Function/feel was much better, left it in about 6 months.

3rd try 2 quarts of MTL, perfection is the enemy of good, had to try it. Changed it in the middle of summer and thought I'd found Nirvana, then came cooler fall weather and it felt a bit notchy.

4th try, had the leftover quart of MT-LV from 2nd attempt, zero cost for an additional data point. Drained 1/2 quart of the straight MTL with intent to add 1/2 quart of MT-LV for 75:25 mix, ended up using 3/4 of the MT-LV for total fill of 2.25 quarts (2.1 liters) and ratio of 66:33. Didn't bother checking level but this amount was not enough to run out of the fill hole. Shifting was markedly better, greater than could be explained by fluid mix alone.

Got me thinking, since it's generally acknowledged that factory fluid is too thin, only specced for mpg, is it unreasonable to suspect that they might have done something similar with fill level spec? As I stated in my first post it's been my experience with many different transmissions that fill spec is always to level of the hole. Was this original design intent for the Fist trans as well, but in the interest of reducing fluid friction for mpg a lower level was specced?

It truly is a great question I wish I knew the answer.
I had a Ford escort and to check the manual transmission fluid level you pulled out the speedometer gear. It was on top of the transmission what a stupid design.





Sent from my LG-LS997 using Tapatalk

 

[grey fist]

Yeah, to summarize my above post, Redline recommended MT-LV does not work well in the Fist transmission. As a longtime Redline fan had the idea to try different viscosity blends of Redline MTL/MT-LV to see if I could make it work. While I definitely could feel a difference between blends, what seemed to make the biggest difference was the one time I overfilled.

 

[PhoenixM3]

I read those threads. Not what I asked. Slightly rephrasing, has anyone ignored the whole 1.67 vs 2 liter vs 20mm below the fill hole and just filled until it dripped like you would with any other manual transmission? If so, how did it work out, any issues?

I did this. Just filled it until fluid started coming out of the fill port. Im about to do this on my 3rd FiST.

 

[grey fist]

Notice any difference? Keep us posted.

 

[PhoenixM3]

I haven’t driven it enough to feel a difference yet. I did put in 2 liters after draining about 1.8.

 

[grey fist]

Bit the bullet and did it. Took 2.3 liters until it dripped. No issues so far at 2 days. Reasonably happy with the Redline but wanted to try the Magic Elixir Ravenol before I called it good and also needed an excuse to try this.

Verdict on the Ravenol: visibly thinner than my Redline mix and feels thinner in the box but works much better than the straight Redline MT-LV which meets Ford spec and was similar viscosity. Got a hint that it might get a bit notchy as it warms up and thins out, but works well enough to give it a long term test. One thing of note, the fluid I drained with only about 6k on it was very black, are factory syncros carbon?

Verdict on filling until it drips: only 0.3 liter more than the 2 liters everyone is filling so don't anticipate any leaks or other issues. Biggest thing to note and primarily why I wanted to try this is the clunk with shifting is gone. Almost like 2.3 liters is design intent.