Ok i am just wondering is it the lnf trany or the diff that makes it lsd? From what i know its the diff and has nothing to do with the tranny? right?

Cause i know a guy selling a LNF diff and wondered if it crossed over to the lsj side

Also was wondering how hard a diff was to put in? if it is possiable thanks guys

 

only thing different between the lsj and lnf trannys is gearing. lsd swap requires dropping the tranny, obviously, its no small task

 

you can swap the transmission assemblies themeselves. but theres other small differences which makes me unsure if you can put an lnf differential in an lsj trans

 

correct. 100% backwards compatible reset the vss for gear ratio...

 

This is sort of on topic here, just wondering, I have an 05 LSJ with 80k on it and the 2-3 gear synchros are shot. Its going to be just as much to rebuild as replace the tranny so my question is. If I order a new tranny for an LNF with LSD, do I now need a clutch for an LSJ or LNF?

 

They say that for the LSJ, the lnf gearing is just a bit too wide, everytime you shift it puts you just out of the powerband. Lsj cars should run the lsj trans. Unless turbo swapped.

 

really? hadn't heard that before. Figured the lower gearing would be better than the LSJ spec tranny for highway and normal driving. The gear ratios are the same just the final thats different right?

 

well for once you are right but there are ways to solve that problem raise your shift point

yz rider your still gay lol

 

the 3.82 lnf final drive ratio does not affect individual gear ratios they are the same. the only difference is the taller final drive ratio means more mph per 1000 rpm in each gear than the LSJ Stock 4.05.
4.45 has the least mph per 1000 rpm

so the shift split remains the same no matter what the transmission as the diff ratio makes no change to individual gear ratios.

the lower the numerical ratio the "higher" the gearing. The higher the numerical ratio the "lower" the gearing.

rev splits are determined in gears by the individual gear ratios NOT the final drive ratio.

all things being equal on the drag strip a HIGHER numerical ratio yields faster et's. ET wins races, not trap speed.

on the road race track it is best to gear the car for maximum continuous rpm in top gear (5th) at the longest straight and then work backwards changing ratios to suit. The widest ratios are at the lower speeds (1-2) and the closest ratios work up to 5th in this case being most desirably the closest ratio.

that means of the possible Final Drive ratios for the LSJ, or 3.82, 4.05 or 4.45, the 4.45 is best. At Daytona the Cobalts hit the rev limiter a little before the end of the straight. Everywhere else its ok.

regrettably, the inividual ratios cant be changed practically speaking.
But its faster to reduce overall top speed in favor of elapsed time down

 

Dude wtf?

 

just giving you ****

 

so i should buy two trannys, one lsj lsd and one lnf lsd... and swap them out hahaha

 

thanks for clarifying john. i always mix those up. lower number/higher gearing, higher number lower gearing. I know your the guy to ask here, simple question but want to clarify before I start ordering parts this week. If I swap out my LSJ MU3 for a LNF spec MU3, do I still buy a clutch for the LSJ or for the LNF? I would think LSJ but IDK for sure.

 

get the upgrade clutch for the LSJ your LNF trans should come with a new LNF tob, you are set. It will be a real nice cruiser with that axle ratio....
2479 at 65 mph in an LSJ, 2250@65 with the new LNF

 

Thanks again John

 

John, I love you

 

okay so the swap went okay. transmission and mounts went into the car, pretty much everything is all the same. only one small difference. only problem is, when the car go put all back together it will crank but no fire. plugged in HPT and saw no DTC's. reflashed the ecu to the stock gm s2 tune. comunicated with ecu okay. still just cranks with no fire. scanning shows rpm, pw, duty cycle, and 6* of timing during cranking. no fuel smell or vapors out of the tail pipe even after some cranking. so I am thinking that the injectors aren't actually opening, but not sure. everything was taken back apart and rechecked, connections were rechecked. So I don't know if its possible that the plugs for the injectors and for the plugs got reversed? Or if its possible that the ECU could have gone bad. It was unplugged and set on a bench for 4-5 hours. IDK WTF is going on. Just cranks and cranks without firing.

Any ideas?

Also, found my map sensor is cracked. I only see the 3bar on CED, is it okay to run a 3bar sensor? Would I need to re-tune anything for it? I'm just running the SC with either 3 in in the winter or 2.8 in the summer. Will be on 80#s too this summer for the 2.8 so don't worry about me running that 2.8 on 42.5's.

 

i am guessing the ecu connector socket females are pushed out of ecu pins are damaged or ditto for the fuse box when you put it back to gether. painstaking pin out testing required...look/ check

 

oh, thankfully it wasn't that bad. I can imagine that to be a PITA. It was the power from the ecu to the injectors. Power line (pink w/ white stripe IIRC) must've been rubbing on the ac condenser hose that runs through there. It was just about completely worn through so naturally as soon as we started moving things around, it broke. Replaced it and she fired right up.

I love this new tranny, the throws are so much shorter than the LSJ's tranny. Its awesome, and John was spot on with the clutch choice. To much more and I don't think it would be a very street friendly car. Just have to reflash the VCM so I know exactly how fast I'm going, forgot about it till this morning on the way to work.

I'm thinking I should have talked to John first about rotated mounts though. I think these TTR's are too stiff for what I want. Probably great for the track but for a DD and occasional track car. Right now, there is too much vibration from the poly. Maybe they'll relax a little after some miles IDK, if not I think I'm going to change them to Powell's mounts.

 

good (great!) that you fixed your problem. i would recommend stage 1 for your car contact Josh at OTTP and say good bye to vibes...LNF trans is sweet, I got one with a short ratio cwp. But noisy on the diff gear on the over run but all good and like you say shifts very good

 

so will i gain by switching over to the lnf tranny, i have my red line set at 72 now with no problems and i run a 2.6 with boltons and meth and coolings.