I purchased a Z spec t5 for my fox from LMR, and it came with some royal purple trans fluid, I put that in and it grinds going into 5th gear if I’m above 2500-3k rpms. I looked online and people said that RP fluid is trash and Tremec themselves said to use non synthetic ATF. Did I ruin my new trans using that RP fluid? Or have any of you ran this fluid/owned the Z spec trans? I’ve maybe put 200 miles on it. Thanks!
Drivetrain Z Spec T5 Grinding
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I run non-Syn ATF in the T5s I’ve rebuilt myself. I believe this is all Tremec has ever suggested to use.
drain it and refill. You’ll likely be ok.
why did it come with RP? Is this what LMR suggests to use?
drain it and refill. You’ll likely be ok.
why did it come with RP? Is this what LMR suggests to use?
- Mar 2, 2015
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I run dex iii in my t5z and t5s. The t5z has a 500 mile break in period. You'd be fine draining the royal pure out and adding dex iii.
If you have an aftermarket shifter make sure its adjusted correctly.
If you have an aftermarket shifter make sure its adjusted correctly.
Sparky714
Well-Known Member
I pulled my T5Z to install a new clutch and drained the non-sythetic fluid. No grinding going into 5th gear before I pulled it. Reinstalled and re-filled with synthetic fluid and it grinds going into fifth. I'm going to drain again this winter and go back to non-syn. It must have something to do with 5th gear being a brass syncro cone instead of the lined one in 1st thru 4th. Maybe synthetic fluid is too slippery for the cone to engage properly?
It won't grind if your real slow going into 5th. Almost like the syncro cone is slipping and it takes a few seconds for the gear speed to match so the syncro works right.I think you’re correct because mine shifts the exact same way. Thanks.I pulled my T5Z to install a new clutch and drained the non-sythetic fluid. No grinding going into 5th gear before I pulled it. Reinstalled and re-filled with synthetic fluid and it grinds going into fifth. I'm going to drain again this winter and go back to non-syn. It must have something to do with 5th gear being a brass syncro cone instead of the lined one in 1st thru 4th. Maybe synthetic fluid is too slippery for the cone to engage properly?
When the World Class T5 was released in the Mustang, Mercon/DexII was the recommended fluid, which was replaced by DexIII in the early 90's. BorgWarner changed the blocker ring material around the same time, changing from a composite material to carbon fiber material in 3/4th gear in the early 90's.
Around 2010, Tremec ceased making the T-5 other than the T-5z. Tremec redesigned the blocker rings again and is what is currently on the market when you order a rebuild kit, or buy a T-5z. These blockers are superior to the older designs and are more "grabby". With with 3 different blocker ring designs out there, it's no wonder why some guys experience bad shifting with one fluid, while it works fine in other T5's. So it's tough to go by other's experience in terms of which fluid to run.
All along the way, I do not believe that Tremec has ever suggested any other fluid other than D3/Merc. This is what I run.
I got this directly off the Tremec website
Some good general info here
Around 2010, Tremec ceased making the T-5 other than the T-5z. Tremec redesigned the blocker rings again and is what is currently on the market when you order a rebuild kit, or buy a T-5z. These blockers are superior to the older designs and are more "grabby". With with 3 different blocker ring designs out there, it's no wonder why some guys experience bad shifting with one fluid, while it works fine in other T5's. So it's tough to go by other's experience in terms of which fluid to run.
All along the way, I do not believe that Tremec has ever suggested any other fluid other than D3/Merc. This is what I run.
I got this directly off the Tremec website
Some good general info here
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I think all of you have made up my mind of going T5 or Tremec 600.....I pulled my T5Z to install a new clutch and drained the non-sythetic fluid. No grinding going into 5th gear before I pulled it. Reinstalled and re-filled with synthetic fluid and it grinds going into fifth. I'm going to drain again this winter and go back to non-syn. It must have something to do with 5th gear being a brass syncro cone instead of the lined one in 1st thru 4th. Maybe synthetic fluid is too slippery for the cone to engage properly?
Tremec TKX 5-spd
Interestinh new trans. https://shiftsst.com/tremec-tkx-5-speed https://www.moderndriveline.com/new-magnum-tkx/ https://bangshift.com/bangshift1320/bangshift1320-tech-stories/bangshift1320-tech-stories-drivetrain/theres-a-new-5-speed-in-town-out-with-the-tko-and-in-with-the-new-tkx/ It’s almost...
stangnet.com
Sparky714
Well-Known Member
Anybody know the price on the new TKX?Tremec TKX 5-spd
Interestinh new trans. https://shiftsst.com/tremec-tkx-5-speed https://www.moderndriveline.com/new-magnum-tkx/ https://bangshift.com/bangshift1320/bangshift1320-tech-stories/bangshift1320-tech-stories-drivetrain/theres-a-new-5-speed-in-town-out-with-the-tko-and-in-with-the-new-tkx/ It’s almost...
fun331
5 Year Member
I run the Z spec in my '89. I tagged the 5th gear synchro the first time I drove it down the 1/4 mile with the new rear gears. Wasn't expecting to have to make the shift to 5th but there was way too much track left not to; and I just tagged it when I shifted but it was enough to make the shift to 5th grind. I drove it around like that for a summer and it wasn't so bad; just a second or two pause between gears and it didn't grind. I was told to try the GM Synchromesh fluid. No grind. Gone. For years now. I put a new clutch in her and drained the fluid. Filled her up with GM Synchromesh again just in case. I hate running Chevy fluids BUT I can't argue with how well it's worked for me.
Mindseye007
Active Member
I have AMS OIL Manual Transmission 75W-90 IN my z-spec t5 and every gear is smooth like butter while shifting noI pulled my T5Z to install a new clutch and drained the non-sythetic fluid. No grinding going into 5th gear before I pulled it. Reinstalled and re-filled with synthetic fluid and it grinds going into fifth. I'm going to drain again this winter and go back to non-syn. It must have something to do with 5th gear being a brass syncro cone instead of the lined one in 1st thru 4th. Maybe synthetic fluid is too slippery for the cone to engage properly?
What rear gears are you running?
You really don't want to run gear oil in a T5z. Tremec specs ATF. I believe they recommended D3 or Mobil 1 ATF, right up to when they decided to make their own fluid.
The reason you don't want to is because the gear oil is too think to properly flow to the small needle bearings that the gears ride on, especially the bearings between the input shaft and mainshaft. It may shift perfectly fine, but these T-5s like to whine like crazy when they get fluid starved due to low fluid or too thick of a fluid over long term. I've pulled apart a ton of T5's with damage in this area.
fun331
5 Year Member
Mindseye007
Active Member
How's your fuel mileage ? I have 4.10 gears and still get great gas mileage if I feather the throttle lol hard not to though...
fun331
5 Year Member
I didn't find the gears were too bad on the fuel economy, but restraint is required. Makes the car lots more fun around town, though she'll get through a tank of fuel if you're having fun.
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