ok so i have a 2005 wrangler 4.0L with the six speed transmission. I want to change the transmission fluid because im sure the previous owner did it and it has about 50k on it now and second is real ruff especially in colder weather. Ive read through the forum and most recommended the royal purple or the MT-90 for 5 speeds. I was wondering if its the same deal with the six speed the manual basically just tells me to use MOPAR.
I also have a six speed in my tj and the move from first to second was extremely ruff when I purchased it (only had 15,000 miles) I took it to the dealer and they said some stuff, probably bs, about tolerances and that only manufacturer fluid will work. They changed it and it did make it noticeably better, though the transition is still noticeably more ruff than any of the other gear changes. I don't know if there was damage done or if it just an issue with these transmissions, but I am interested to hear what the others on here have to say.
I have the same Jeep, same year and I recently changed mine at 38k. I wasn't sure it had ever been done because it was shifting a little rough. After much searching on here, I decided to go with Royal Purple Synchromax. I'm glad I did because it made a noticeable difference. Now, I can't say whether that is because of the brand or just the fact that it is fresh, but in any case, it's better and I'm happy. I'm not a Royal Purple freak or anything like that.
Originally Posted by flint
I don't know if there was damage done or if it just an issue with these transmissions, but I am interested to hear what the others on here have to say.
If I had to pick one transition in mine that is rough, it's from 2nd into 3rd. It's not terrible, but definitely noticeable. 1st to 2nd is fine.
The main issue is that the Wrangler I purchased has a 3 inch body lift kit and the shifter is hitting the plastic piece that holds the shifter boot cover on.
I took it off yesterday and trimmed the metal that is supposed to protect the plastic to give me the extra room to shift.
I am concerned that the 1st to 2nd syncro is already bad. It grinds a little and it does not feel smooth going into 2nd gear.
I had a similar issue with my S2000 and when I put the GM Synchromesh Friction Modified into that transmission, everything got better.
I have no problem rebuilding the transmission myself, rebuilt my 4 speed in my Cosworth Vega several times. I just don't want to have to do this to a vehicle with only 45000 miles on it.
I am also not looking forward to removing the transfer case and the transmission.
I just looked at the Royal Purple site and they suggest their Synchromax as a replacement, but the most interesting thing I noticed is that they also that they do not always recommend their fluids. They actually recommend the OEM products for some.