Gearbox oil capacity
- Thread starter Janis
- Start date
Steve Hoelscher
True Classic
Dry Fill is 3.2 quarts. Typically, on a drain and refill, 3 is adequate but don't leave it low. You'll oil starve 5th gear.
You're using Redline MTL right?
You're using Redline MTL right?
Bjorn Nilson
True Classic
As far as I understand you cannot overfill it. The filling hole is the correct level.
The Redline bottles is very close to a liter.
Steve Hoelscher
True Classic
Oh, there are indeed ways to overfill the transmission. Heck, I have done it myself without realizing it. Lessons learned. 
Bjorn Nilson
True Classic
After replacing my stuck gearbox I filled my working transmission that way, with the car standing flat on the garage floor. Do you think I should drain the oil and start over again? I thought the filling plug is placed on the side on a specific height for a reason.Oh, there are indeed ways to overfill the transmission. Heck, I have done it myself without realizing it. Lessons learned.
Janis
True Classic
@Bjorn Nilson had You found locally Redline oil? So far I have no luck here in Latvia, will make few calls later.
myronx19
True Classic
I was actually going to ask you about this - I have intentionally done it! I would lift the rear of the car a bit, which puts the fill port a little higher up. I can't say how much extra goes in, but I figured it wouldn't hurt - other than extra drag if the gearset was submerged. I didn't get any leaks. If anything, it was a few extra ml.
Interestingly - I have a spare 5spd X1/9 transmission with the fill port in a different location. At first I thought it was a Strada gearbox, but it doesn't seem to be. Wonder how that came to be.
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DanielForest
True Classic
It must be a "Hoelscher-rebuild". End-up with an extra part at the end of the rebuild, so he found a place to put it.
Steve Hoelscher
True Classic
Overfilling is an interesting dichotomy. On one hand, the additional fluid volume can improve heat dispersion and the higher fluid level could improve lubrication in severe service. On the other hand, raising the fluid level can increase aeration which can, in some cases, reduce lubricity and retain heat (the air in the bubbles prevents heat dissipation. I have tried overfilling a couple of road race units to see if there is any noticeable difference in temp or wear but results were inconclusive. Because of this I recommend maintaining normal fill levels and add an oil cooler if temperatures are extreme.
Years ago I rigged up a neat little rig to fill the transmission easily. It was a hose fitted to a funnel that all fit neatly next to the water tank. I inserted the hose in the fill hole and filled until fluid ran out. The problem was the hose, which fit over the funnel easily and provided adequate flow, blocked much of the fill opening and thus I didn't see any overfill until it was well above the bottom of the opening. It probably had a full quart of additional fluid and on the next hot day at the track, it purged some fluid out the vent. At the time I had no idea why. And was shocked when a bunch of fluid ran out when I removed the fill plug.
Jacking the rear of the car will raise the fill plug relative to the rest of the case so you can overfill that way. An easy way to underfill is to jack up the left side and fill. In this situation, much of the case housing the gearset is now raised relative to the fill plug.
Rupunzell
Bernice Loui
Fill the transaxle on level ground. This can be done by making or purchasing a funnel with an attachable hose. The hose cannot be larger than 1/2" OD. Have used thin wall silicon tubing or Tygon clear tubing attached to the end of a funnel, these work.
Remove the filler plug on the side of the transaxle.
Route the filler hose from the top of the engine compartment into the transaxle filler.
~About 24" to 30" of tubing should reach (routed towards the LH rear wheel) the transaxle filler from the top of the power train compartment.~
Exxe must be on level ground before filling.
Pour in the specified Fiat Service Manual amount of transaxle oil (3 liters or 3.2 quarts). Keep in mind filling is easy, drain is difficult.
Remove the filler funnel with filler tube.
Once filled, reinstall the filler plug.. DO NOT over TORQUE the filler plug, the risk of cracking the casting is very real and happens more than folks realize. Both filler and drain plugs are tapered threads which imposes a high expanding force on the threaded boss of the casting causing, this can cause the casting to crack.
Bernice
Remove the filler plug on the side of the transaxle.
Route the filler hose from the top of the engine compartment into the transaxle filler.
~About 24" to 30" of tubing should reach (routed towards the LH rear wheel) the transaxle filler from the top of the power train compartment.~
Exxe must be on level ground before filling.
Pour in the specified Fiat Service Manual amount of transaxle oil (3 liters or 3.2 quarts). Keep in mind filling is easy, drain is difficult.
Remove the filler funnel with filler tube.
Once filled, reinstall the filler plug.. DO NOT over TORQUE the filler plug, the risk of cracking the casting is very real and happens more than folks realize. Both filler and drain plugs are tapered threads which imposes a high expanding force on the threaded boss of the casting causing, this can cause the casting to crack.
Bernice
Bjorn Nilson
True Classic
Redline products are generally available here in automotive shops and online. I went for MT-90 as I expect the turbo to add more heat due to power. The most expensive oil I ever bought.
Bjorn Nilson
True Classic
Good price. I paid 38,50€ per liter.*found one shop, have to make preorder and 20€ per liter, ~1month waiting, could be worse
Dr.Jeff
True Classic
Because the end of most funnels is so large, and therefore the fill hose so big, I made it a little easier by sticking a hose barb 'backward' into the distal end of the fill hose. By backward I mean the NPT threaded end of the barb is stuck into the hose so the narrower "barb" end is still exposed out the end. Basically making a reducer fitting. That smaller diameter of the barb allows me to see past it and into the trans fill hole. Naturally that smaller diameter also slows the filling rate, so a bit of a trade off. But you could do most of the fill by volume without the barb in place, then add the barb to finish it off.
Regarding the fill volume. I think Steve stated this earlier, but there is a difference between the volume of a "drain and refill" vs a "fresh overhaul and fill". A lot of oil oil is left in the trans when just draining it as opposed to a complete tear down and cleaning. I'm not sure what that actual amount is in terms of volume though. But I'm always amazed at what is left behind when you open the case. It is quite a lot and it's the dirtiest nasty old oil with a lot of junk and metal in it. I've even flushed a trans prior to opening it just to see how well it cleaned things out. While the flush did improve most of the internal areas, it really didn't affect this residual yucky oil any.
Dr.Jeff
True Classic
Wow, that's over $45 USD per US quart. Times three, you just increased the value of your X by almost double!
Being a US product, and not cheap to begin with here, I guess it doesn't surprise me too much. Much like what we pay for top European brands of things.