Engine/Transmission (1998.5 - 2002) 6 Speed Gear Grinding (5th - 6th)

[J Trade]

New to the forum, Ex Powerstroker!!!!!

Just purchased a 2001 HO 6 Speed. When shifting normally from 5th to 6th its grinds a little. If I take my time, and let the engine spool down a bit, its OK. Had the transmission fluid changed with Mopar Fluid using the number on the side of the trans, but no difference. Truck has 99k on it, runs great otherwise. Any suggestions, or additives I can put in to make it shift better?



Also looking at a B-box chip, but didn't find anything searching the forum, good, bad, ????

Thanx!



PS Got 19. 5 mpg on the trip home from buying it! My powerstroke never saw 16!!!! Awesome!

 

[Texas Diesel]

There has been a lot of discussion on this subject, do a search on NV5600 lube.



Some have used synthetic 5W-30 Motor Oil with good success for approx 100k miles, but I prefer an oil rated and formulated for manual transmissions not engines.



Others have used RedLine MTL, I prefer Royal Purple Synchromax available from JC Whitney, there are lots of choices other than OEM (since you are out of warranty)



Disclaimer: I dont sell lubricants and dont profit 1c no matter that you buy.

 

[cpeters]

Royal Purple is the one I use and it smoothed out my shifting as well as getting rid of a little grind or pop that I had, for your 6spd you will need synchromax.

 

[klenger]

It might be broken.

 

[J Trade]

Thanx for the replies. I hate to switch to a synthetic after reading all the bad posts in past, but at this point that may be my only option besides pulling it out and having it checked. I have a feeling it may be the synchro going bad.



Anyone else run accross this problem?