2011 Road King

[xlfan]

Is there any good reasons NOT to run 80/90W transmission oil in the gearbox of these 6-speeds?

[PoorUB]

Any problem? Nope! It is probably better than what HD will sell you for it.

I run 75W-140 synthetic.

[jmorton10]

I've never used it before (I have used Redline HD Shockproof in my trannies for years) but when I completed installing my new Baker Grudgebox a few weeks ago I filled it with Spectro 75-140 because Baker recommended it, & I know it works so well I will keep running it.

~John

[Ohio HD]

No reason at all not to use 80w90 gear oil. Use synthetic if you want, it can only help.   

[No Cents]

  I've tried numerous brand name 75w140 gear oils in my tranny over the years. The Lucas Oil synthetic 75w140 makes a noticeable difference over all other brands I've tried. My tranny shifts like butter. The only place I have found that carries it around me locally is Pep Boys. The Lucas synthetic 75w140 is worth every penny in my book.
  If you have the means to get a bottle of this stuff...you won't be disappointed with the results. 

     [attach=0,msg1339631]

[PoorUB]

I have used what ever 75W140  syn I  can find. Can't say I notice any difference between any of them. I couldn't say for sure what went in last time, maybe Redline, what ever O'Reily has on the shelf.

I will say with the 75W140 the tranny is not as noisy as it was with 90 weight.

[jmorton10]

  I've tried numerous brand name 75w140 gear oils in my tranny over the years. The Lucas Oil synthetic 75w140 makes a noticeable difference over all other brands I've tried.

Hey Ray, what mods have you done to your tranny??

~John

[No Cents]

  John...it's bone stock. It's still hanging in there. I've been trying to find a low mileage 6 speed gear set to send to R&D for his lovin.
  I've tried Valvoline, Royal Purple, Spectro...all with basically creating the same feel out of the tranny when shifting. The Lucas gear oil made such a difference that I can actually feel the added smoothness over the other brands. It was just some personal testing that I did with gear oils. I can honestly say my tranny shifts smoother with the Lucas in it.

[jmorton10]

I looked it up & Amazon sells it for $16 a quart.

I'll have to give it a shot next change I think.

My setup now shifts so smooth now that it's hard to imagine it getting any better but I will certainly try it.

~John

[No Cents]

   that's a better deal than I get at Pep Boys.    I think it's like almost $20.00 for a bottle of it around here.
Just make sure you get their "synthetic" 75w140. It's pretty amazing stuff.

[kd]

John, I find that my GrudgeBox shifts so slick that I sometimes wonder if I pushed the lever far enough.  BTW I use the Spectro 75 / 140 too

[jmorton10]

John, I find that my GrudgeBox shifts so slick that I sometimes wonder if I pushed the lever far enough.  BTW I use the Spectro 75 / 140 too

Same here. The first time I dropped it into first gear I wasn't sure anything happened, there was no clunk at all & I had to slowly feather the clutch to make sure it was actually in gear. (I think we are both using the same clutch too ??)

Obviously the Spectro is good stuff if we are both getting the same results with it.

~John

[jmorton10]

   that's a better deal than I get at Pep Boys.    I think it's like almost $20.00 for a bottle of it around here.
Just make sure you get their "synthetic" 75w140. It's pretty amazing stuff.

https://www.amazon.com/Lucas-Oil-LUC10121-Synthetic-Transmissio/dp/B000BCKWVE/ref=sxbs_sxwds-stvp?cv_ct_cx=lucas+oil&dchild=1&keywords=lucas+oil&pd_rd_i=B000BCKWVE&pd_rd_r=aa488cab-5283-4797-b46c-f1ac6020aac2&pd_rd_w=lkUqo&pd_rd_wg=COUE9&pf_rd_p=967d8720-e4cf-4d5d-9da3-53f47ca634a3&pf_rd_r=FXTBPJQWBKAQQK5K0Q51&psc=1&qid=1585579637

~John

[kd]

John, I find that my GrudgeBox shifts so slick that I sometimes wonder if I pushed the lever far enough.  BTW I use the Spectro 75 / 140 too

Same here. The first time I dropped it into first gear I wasn't sure anything happened, there was no clunk at all & I had to slowly feather the clutch to make sure it was actually in gear. (I think we are both using the same clutch too ??)

Obviously the Spectro is good stuff if we are both getting the same results with it.

~John

Yes, same clutch. I expect both Bandit and Baker's testing has shown it to be the most effective for their purposes and I'm comfortable with using what they suggest at this point. I am glad they both recommend a similar product. There must be a connection in construction of the recipe.  I don't see any point in trying to fix anything that isn't broken (yet  ).  If I was still using the OEM gearbox like Ray is and I noticed any lack of quality shifting, I might try his suggestion.  As it stands I'm good with the Spectro.

[No Cents]

I would stick with the Spectro if I was you guys so you would never have an issue with Baker.