so I just put an LSD in my 2000 civic si trans and now it wont go into reverse. it will go into 1st through 5th but no reverse. What could be the cause of this. I took pics of everything and put it back together the same way I took it out. I have searched around but I haven't seen anything that is the same.

The only other thing I don't know is if I need to shim the diff. not really sure where it goes what side it goes on if I even need one. I don't even know if it has a shim to begin with unless I just didn't recognize it. Its an obx LSD (I know they are cheap but I got to pay for medical school and an apartment)

any help would be great thanks a lot

 

Your failure to properly shim the diff could "theoretically" lead to premature transmission failure in the form of a cracked/warped case and/or differential bearing failure. To minimize your chance of having this happen, try to avoid instantaneous torque transfers; in other words, don't accelerate and suddenly take your foot off the gas and use the transmission to decelerate. Going from acceleration to deceleration, and vice versa, effectively "slams" the un-shimmed differential into the side of the trans housing.

 

Also, about the reverse gear - you need to be more specific. Can you move the shifter into the position at least? Reverse gear is a bit more complicated than the others because it has a cam-lock that prevents you from accidentally mis-shifting into reverse. If you assembled this part wrong, it won't even let you move the shifter into the reverse position.

 

About the shim- how do I know what size to use where it goes I am clueless. If the diff is the same height as the original I wouldnt need to re-shim would I

For reverse- I can move it to every gear pretty smothly and I can get it to go into reverse now BUT it is really hard and once I get it in there it is almost impossible to get out.

Thanks

 

nightly bump for some help!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fastasssr20 &raquo;</TD></TR><TR><TD CLASS="quote">About the shim- how do I know what size to use where it goes I am clueless. If the diff is the same height as the original I wouldnt need to re-shim would I </TD></TR></TABLE>

You always have to re-shim because it's never the same height. It's a bit complicated to explain - try locating a Helmes PDF online and downloading it. It explains everything.


Sorry, I don't recognize those reverse gear symptoms . Did you mess with the gear sets at all?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Semtec &raquo;</TD></TR><TR><TD CLASS="quote">

You always have to re-shim because it's never the same height. It's a bit complicated to explain - try locating a Helmes PDF online and downloading it. It explains everything.


Sorry, I don't recognize those reverse gear symptoms . Did you mess with the gear sets at all?</TD></TR></TABLE>

You don't know enough about transmissions to even begin to attempt to diagnose a problem, all you're doing is confusing the OP.

Of course he messed with the gear sets, he has to in order to install the LSD.

You'll have to recheck the reverse idler gear and your shift fork assembly. Perhaps you forgot to put the reverse idler gear in? I've done that

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bense &raquo;</TD></TR><TR><TD CLASS="quote">

You don't know enough about transmissions to even begin to attempt to diagnose a problem, all you're doing is confusing the OP.

Of course he messed with the gear sets, he has to in order to install the LSD.

You'll have to recheck the reverse idler gear and your shift fork assembly. Perhaps you forgot to put the reverse idler gear in? I've done that </TD></TR></TABLE>

?

I didn't want to throw out a guess if I can't help him. I do however know about the shim situation, which is why I tried explaining that to him. And no, you don't need to mess with the gear sets to install the LSD, all you do is pop out the mainshaft/countershaft and set them aside so you can get to the diff carrier. Unless he was also replacing a grindy gear, we can assume that he didn't mess with the gear sets, which rules out one possibility. As for the shift forks; I don't see how you can install those the wrong way. In order for the case to even bolt back together, you need the top of the shift rods to be perfectly aligned; that rules out another possibility.

I mentioned the cam-lock mechanism because that has a very real possibility of keeping him out of reverse gear, which is it's purpose. I'm not sure about the reverse idler gear, but if he forgot to put it in, wouldn't he have no reverse at all? That wouldn't explain the symptoms of being hard to go in/out of gear.

 

Check to make sure the shift fork for the reverse gear isnt sitting on top of the gear.

 

I am not sure I under stand what you mean. How could it be on top of the gear. all the other gears work fine just not reverse

 

well I check the clearance for the shim issue and it appears I am within the specs. so I guess you dont always need to shim it. Maybe I got lucky but still no reverse!!

 

You always need to shim it. You must be reading your feeler gauges wrong. The bearing-to-housing clearance should ideally be zero. The bigger the gap, the shorter the life of your diff bearings.

 

the smallest feeler gauge I had was .002 and it didnt fit between the bearing and the 80mm c clip looking thing that is in there or the housing

 

what happens when you actually pull the shifter back into reverse? do you you feel and hear the reverse idler gear slapping down? if it feels fine, but you don't hear it then, like bense mentioned, the idler gear might not be in. if you're sure you put it back, it could be something up with the top end of the mainshaft where 5th reverse synchro sleeve is. so report back how the shifter feels when you actually put it into reverse if it even goes and stays.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fastasssr20 &raquo;</TD></TR><TR><TD CLASS="quote">the smallest feeler gauge I had was .002 and it didnt fit between the bearing and the 80mm c clip looking thing that is in there or the housing</TD></TR></TABLE>

Well no kidding - you're supposed to remove the original shim and put in a much, much thinner one because the OBX carrier is taller than the OEM unit.

If you left the original shim in place, you've probably got a 0.0000" clearance because you torqued the trans case down onto the carrier. That scenario is just as bad for the diff bearings.

Of course, you could be the 1 in a million person to have it fit with the factory shim... I've just never seen it before.

 

well the guy at honda told me I had to measure it with the original spacer in there. the diff moves and spins fine at least I think. he wheels moved the first time I had the trans in the car when the reverse didnt work. I guess I will take it out and measure it that way.

 

If I were you, I'd find a Helms PDF online somewhere and download it. It really walks you through then entire trans assembly process.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fastasssr20 &raquo;</TD></TR><TR><TD CLASS="quote">well the guy at honda told me I had to measure it with the original spacer in there. </TD></TR></TABLE>

Well that's what you'd do if you were re-installing your original diff carrier. But since the OBX carrier is taller, it's best to remove the shim, bolt the housing back together, and measure the gap. It's usually around .5mm, in which case you can use a B18B oil control ring as a shim since Honda doesn't make a differential shim smaller than 1mm.

FYI - if you did in fact pinch the differential because the shim is too big, the unit will still spin freely because you are only pinching the outer race of the carrier bearings. Again, it's not a crisis situation, but since you have to pull the case apart to fix the reverse gear anyway, you might as well fix the shim. An oversized shim could "theoretically" lead to oil leaks (warped case) or premature bearing failure.

 

well I got everything fixed reverse and all. the shim was infact perfect I guess I was the lucky million haha. weird it was exact on the dot. thank you all for all ur help

 

Well, dish out the specifics - what was the problem?

 

to tell u the truth I dont know, I took out the diff to measure it up and when I put it back together I just made sure everything looked square and it worked