Mega Users seabass07 Posted May 18, 2011 Mega Users Share Posted May 18, 2011 I hope engine braking isn't bad for it. I did a hell of a lot of it while towing a 4k lb trailer for 4500 miles. A couple of times I was able to make the trans shudder on engine braking, but only under intense engine braking slowing to a stop at the base of a steep hill. I definitely tested the limits of it, but it took a LOT of force for it to shudder. I was under the impression that the front brake didn't actually do anything other than engine braking, but according to the manual it is used for engine braking under 1,2, and 3. And it also holds power for 3rd, 5th and R always. I'm surprised that you were able to destroy it without crazy engine braking though. Maybe it wore out during 2-3 shifts. If I remember correctly from your info on the front brake, it contained less frictions/steels than other clutch packs. Link to comment Share on other sites More sharing options...
ClimberDHexMods Posted May 18, 2011 Author Share Posted May 18, 2011 I generally defer to Frank_ster whenever I simply don't understand something, since he's the only one active on these boards that actually knows anything about auto transmissions. And here we are reading the same manual, getting 2 different explanations of what the front brake does. A little FreeSSM would clear it right up... need to get my car safe enough that my wife will drive it so I can watch the laptop screen [CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER] Link to comment Share on other sites More sharing options...
ClimberDHexMods Posted May 22, 2011 Author Share Posted May 22, 2011 For a while I've had two fully disassembled 05 5eat valve bodies sitting on my table. I put one back together, modified, for the first round of testing. Haven't drilled any holes, interested to do a before/after without/with holes to see what difference it makes. Haven't swapped it out yet, don't know when I'll get the time. [CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER] Link to comment Share on other sites More sharing options...
WANTED Posted May 22, 2011 Share Posted May 22, 2011 On man, then anticipation is killing me. Trying to patiently wait for the results. Link to comment Share on other sites More sharing options...
xero287 Posted May 22, 2011 Share Posted May 22, 2011 I can has 5E(xtremely)A(wesome)T(ransmission)? Link to comment Share on other sites More sharing options...
frank_ster Posted May 24, 2011 Share Posted May 24, 2011 I hope engine braking isn't bad for it. I did a hell of a lot of it while towing a 4k lb trailer for 4500 miles. A couple of times I was able to make the trans shudder on engine braking, but only under intense engine braking slowing to a stop at the base of a steep hill. I definitely tested the limits of it, but it took a LOT of force for it to shudder. I was under the impression that the front brake didn't actually do anything other than engine braking, but according to the manual it is used for engine braking under 1,2, and 3. And it also holds power for 3rd, 5th and R always. I'm surprised that you were able to destroy it without crazy engine braking though. Maybe it wore out during 2-3 shifts. If I remember correctly from your info on the front brake, it contained less frictions/steels than other clutch packs. 99 % of wear to automatic trannys is from shifting, once in a speed its fine. so if your in what ever gear and using it as engine braking you fine. what is bad is when the tranny down or up shifts slowly " for comfort" its very damaging. and i found the down shift from 4th to 3rd to be a little drawn out. i always help out by doing a rev match ( giving the engine a shot of gas ) how ever the tcu kinda freaks out .. the tcu does not know your intention. and if you do it a certain way it works nicely if you do it another way it will make the shift take even longer. Now that's thinking out of the boxer! fyi all 05 + legacy's have built in code reader Link to comment Share on other sites More sharing options...
Mega Users seabass07 Posted May 24, 2011 Mega Users Share Posted May 24, 2011 I tried rev matching, but when you come to the top of a hill going 50 and see a red light at the base and there's a 4k lbs trailer in back, you think oh shit and slam on the brakes and downshift. I don't think I did too much damage, but some of those downshifts definitely made some clutches shudder. I doubt I did anything harmful, since it still works fine. It scared the hell out of me though. After it happened the first time, I got into the habit of slamming on the brakes as hard as I could while downshifting for engine braking. I usually didn't have enough time to rev match since giving it a little gas is counter productive when you need to slow the f**k down fast. When I say I'm worried about the engine braking I was doing on the trip, I'm specifically referring to the downshifts. I know once it's engaged it can take any abuse I can throw at it. Link to comment Share on other sites More sharing options...
ClimberDHexMods Posted May 24, 2011 Author Share Posted May 24, 2011 With certain aftermarket TCUs you can possibly set it up one way or another to intercept and blip the throttle body motor or the accelerator pedal position sensor for a fraction of a second to "downshift rev match" like the 08s and some Zs do. Just throwing it out there, if TransGo beats me to a product release with their 05-07 5eat kit, and you want it installed, please consider me as an installer. I say this because I got a call from the company that made me the prototype 5eat front torque-sensing diff, and I do need to devote my car time first and foremost to getting that installed and tested. That means getting off my butt and rebuilding my 5eat, which means test-fitting the new clutch packs to see exactly how much piston to lathe down. At the same time, need to get the center diff bushings done at the machine shop, then measure them (all of them) and ship them off. Lots of car work to do... need to replace turbo/UP gaskets so I can actually make boost. Need to get the car aligned so the tires stick to the road (seriously). All that said, the valve body project is the most interesting to me by far, and I REALLY want to do something impactful with that, as it's overdue for some attention. Heck the Nissan RE5R05A guys have a bunch of different options. Stillen, Maximum Tuning, GTM, IPT, Level 10. The forum chatter and elsewhere with the Z crowd indicated some shift harder than others. One shifts so hard it basically slams the living crap out of the car at WOT (not what most of us want). But the point is there is a benefit to be had if variations can be made. Fine-tuning may lead to better shift tuning for all. Who knows. [CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER] Link to comment Share on other sites More sharing options...
fishbone Posted May 24, 2011 Share Posted May 24, 2011 Why worry so much about rev-matching in day to day traffic? Just slow down and let the 5EAT downshift on it's own, or wait your downshift until the revs are low enough so it won't load the transmission when you shift. Link to comment Share on other sites More sharing options...
Mega Users seabass07 Posted May 24, 2011 Mega Users Share Posted May 24, 2011 During day to day driving, I think it is pointless unless you are just trying to avoid the car jerking. But it would be smooth and take load off of the transmission when towing or when high rev downshifts are necessary to keep brakes from overheating. If I remember correctly, the front brake has very few frictions/steels compared to the other clutch packs. Link to comment Share on other sites More sharing options...
fishbone Posted May 24, 2011 Share Posted May 24, 2011 I'd rather replace brake pads than clutches, so I try to avoid loading the transmission by downshifting when not needed. That said, in the winter I do use engine braking for safety. Link to comment Share on other sites More sharing options...
RIPjeep2002 Posted May 24, 2011 Share Posted May 24, 2011 I drive in manual mode all the time. then only time I downshift is when in 5th and need to pass on the highway i downshift to 4th,OR in the winter. the rest of the time I let the TCU downshift itself. Link to comment Share on other sites More sharing options...
scoobydoobie Posted May 24, 2011 Share Posted May 24, 2011 I engine brake all the time. But I do it carefully. I make sure I do it so that the RPMS jump up to 3K, occasionally 3.5K MAX. Link to comment Share on other sites More sharing options...
ClimberDHexMods Posted May 24, 2011 Author Share Posted May 24, 2011 (edited) It's more complicated than that. There's a lot going on in every gear, except 4th which is a slightly more simple 1:1 ratio. Frank_ster still gets it much better than I do. The forces are tough for me to figure. For instance the front brake locks the front sun gear in place, causing the other gears in the planetary gear set to rotate around it differently. But what force is transmitted back to the front brake? Almost nothing? Something considerable? Add that this needs to be considered during the dynamic environment of a gear shift. It's a lot to mull over. What I know for sure is stock VB + power = ClimberD has ruined several clutch packs Edited May 24, 2011 by ClimberD@HexMods [CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER] Link to comment Share on other sites More sharing options...
Tomkat1127 Posted May 24, 2011 Share Posted May 24, 2011 Why worry so much about rev-matching in day to day traffic? Just slow down and let the 5EAT downshift on it's own, or wait your downshift until the revs are low enough so it won't load the transmission when you shift. This is what I do and have always done. So, what or how do I do this rev-matching downshift stuff on my 08? Link to comment Share on other sites More sharing options...
fishbone Posted May 24, 2011 Share Posted May 24, 2011 Your 08 should rev-match automatically. This conversation is besides the point anyway. We should take it to the 5EAT Pride thread. Link to comment Share on other sites More sharing options...
snow05gtRI Posted May 24, 2011 Share Posted May 24, 2011 edit: forgot this was the VB thread, moving the post to the 5EAT pride thread. Link to comment Share on other sites More sharing options...
Mega Users seabass07 Posted May 24, 2011 Mega Users Share Posted May 24, 2011 lol...sorry for the derail. Link to comment Share on other sites More sharing options...
sschmelcke Posted May 24, 2011 Share Posted May 24, 2011 I just read this thread and i am not royally pissed off that i took a day off from work, drove down to IPT and paid them almost a grand for a VB/tranny flush. On the plus side the car is sold. Link to comment Share on other sites More sharing options...
lieutenantcolumbo Posted May 25, 2011 Share Posted May 25, 2011 I just read this thread and i am not royally pissed off that i took a day off from work, drove down to IPT and paid them almost a grand for a VB/tranny flush. On the plus side the car is sold. What I think is funny is if you go back and read a lot of the posts people made about how great the car shifted after installing the IPT valve body. Higher line pressure sure must cure a lot of ills, either that, the placebo effect, or people didn't want to admit blowing $769 + install costs. No doubt the higher line pressure did save a lot of trannys, but I don't think it really helped the overall shifting much. Link to comment Share on other sites More sharing options...
sschmelcke Posted May 25, 2011 Share Posted May 25, 2011 When I first took the car for a ride with them I was like there really isn't much of a difference. He said it was because the tcu tried to correct for it and it was the best they could do. They tranny started slipping at stage 3.5. Link to comment Share on other sites More sharing options...
fishbone Posted May 25, 2011 Share Posted May 25, 2011 What I think is funny is if you go back and read a lot of the posts people made about how great the car shifted after installing the IPT valve body. Higher line pressure sure must cure a lot of ills, either that, the placebo effect, or people didn't want to admit blowing $769 + install costs. No doubt the higher line pressure did save a lot of trannys, but I don't think it really helped the overall shifting much. The fact that I paid all that money for that little does not change how the valve body works. Now that warm temps are here, it shifts even better. I am still happy with it, just not happy with the ROI. Link to comment Share on other sites More sharing options...
ean611 Posted June 2, 2011 Share Posted June 2, 2011 ClimberD, any updates? Link to comment Share on other sites More sharing options...
snow05gtRI Posted June 2, 2011 Share Posted June 2, 2011 any progress on yours, eitan? Link to comment Share on other sites More sharing options...
ClimberDHexMods Posted June 2, 2011 Author Share Posted June 2, 2011 Nope, I need to put in a block of time wrenching on my car, and the trouble is I don't have that time. Maybe this Sunday. I don't know if I posted it, but I couldn't find a used 08 VB like I had hoped. That complicates things. [CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER] Link to comment Share on other sites More sharing options...
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