Royal Purple01512 Synchromax Manual Transmission Fluid Pack of 6 Quarts

I have a 88 F250 with the ZF5 (5 speed) transmission and a 460 (7.5l) V8. This stuff is awesome, I've always liked Royal Purple oil, and have used several other products with good result. I decided to change out my gear box oil/ATF and wanted something that offered a little bit better protection for a manual gearbox, namely better protection for the "yellow metals" (like brass and Copper) that are used in manual transmissions. I was looking just to replace my existing fluid with something a little better, what I was NOT expecting was a significant change in performance... my gearbox now shifts MUCH more smoothly than before, it used to be a little hard to get into 2nd (you normally start in 2nd on a ZF5 when not rowing), especially if the gearbox was really cold. This thing is now as easy to shift as I imagine it was when it was BRAND NEW! It took about 50-100 miles for it to have this effect, but let me tell, it's awesome (and was entirely unexpected)! If you have a Ford with a ZF5 or ZF6, this is the right choice for your gearbox (oh, and transfer case too!) and although it's a little pricey, it's worth every penny! The 6 quart pack was enough to do both my transmission and transfer case with about a third of a bottle (12oz) left.

I'm using this in an RPM Level VI TR6060 in a Chevrolet SS. I'm not brand loyal; this is what RPM recommended. Since they built the transmission, I'll go with their recommendation. I can't say it's any better or worse than anything else I've used. In the stock transmission, I preferred Motorcraft Mercon V to the GM MTL, only because the shifting felt better. So far, this feels like it's somewhere in between the GM MTL and Mercon V.

This product performed far better than I expected. The gear box in my 30 year old Land Rover Defender is tired and worn out and the shifting is finicky. I flushed out the gear box and filled with Royal Purple hoping it might help a little but, my god, it's like new now. Can't believe how nice the shifting feel is Royal Purple!

I just bought a Chevy Silverado...the one I always wanted...regular cab..short bed..4.8L V-8 and manual 5 speed...the guy I bought it from was meticulous in his servicing of it. It's a 2004 with 125,000 miles..not a squeak on it..really tight....engine sounds good..runs great...transmission the same way...I decided I was going to go with Royal Purple from one end of the drive train to the other...the engine, the transmission, and the rear end...drained the engine oil and removed filter...put on a new Royal Purple filter and 6 quarts of Royal Purple 5W-30 oil..what the factory recommends..the I drained the manual transmission oil...pit in Royal Purple Synchromax....I ran out of time to do the rear end but I will do that in the morning...took her for a spin...I thought to myself..I want to see some astonishing results like everyone else....Strike me dead with Lightning...I thought this truck was quiet and tight...I didn't realize the noises this taken away....All I can say is that I feel like I'm driving around a piece of velvet....I am so glad!!!! I decided to go with Royal Purple...I'm sold....Now for the rear end tomorrow...I'm thrilled....

Bought a used 2010 Challenger RT (6-speed, Tremec 6060) with 35k miles on the odometer. Previous owner had no record of MTF change so I opted to do it as preventative maintenance based on age. I noticed immediate difference with smoother shifting and rowing through gears are less notchy. The 6-speed on Dodge isn't as silk as a Honda but easily 50% improvement overall. Would recommend