Topic: after 4.88 installation, tranny noise

[bestos]

hey guys, installed my new 4.88 gears in 30 and 35 thursday.

been taking it easy, not driving more than 15 min, not going faster than 50mph, gears are GREAT, so much nicer,

However, :) when i am decelerating, the transmission is making this small noise and bucking just a little bit, never had this problem until new gears installed, i just would not think it is a natural sound/occurence.

any help for those who have installed new gears in a 2.5L

95 wranger with 32" bfg mt

PS, added this to jeepforums:  there is a bit of whirring noise as engine winds up, comes from underneath not engine.

someone suggested there that backlash may be just a bit too tight.

Any help would be great.

[Jeffy]

What do you mean by bucking?  What kind of noise?  Can you localize it to the transmission or is it the T-case.  I think it's unrelated to the gears.  There shouldn't be any change to the transmission or T-case.

[bestos]

ok, as far as the decelerating part, when i let go of pedal, as the revs drop below 2k, the tranny makes a slight noise, but it is only intermittant, with an occurence about 1 second on, 1 second off,  it is a low frequency osciallation.

Jeffy, the entire jeep is not bucking, but it just feels like the transmission is lurching during the frequency of that noise, but it is a just a small lurch,

driving and shifting, there are not problems of any.

if i downshift to higher RPM to continue to slow the jeep, the rpms jump above 2k and the sound is gone until i drop near 1800 or 1900, but during acceleration, no such problem.  hope that helps.

[bestos]

bump,

boss at work suggested to purchase some new U-joints from driveshaft because new R/P and all is tight and new, and the old system was more than likely a bit looser (real word?).   he said that stress at the U could cause the noises in the T-case, which i may be hearing.

[Jeffy]

Well, it's probably a good time to replace those anyway.  Seems like a weird explanation but it's a good guess as any.

[bestos]

thanks, yeah, interesting explanation i thought myself, but worth a try,

been doing a lot of necessary maintanence lately anyhow, most of which has never been done on 11 year old jeep,

i will be doing the U-joints this weekend and if the sound persists, i am gonna be taking the rear Diff cover off and look at the R/P and use some more marking compound and recheck the pinion preload.

[Jeffy]

Remeber to check the pinion bearing preload you need a dial type in-lbs torque wrench and not a ft-lbs torque wrench.  Some guy on Jeepforums.com used a ft-lbs and then wondered why his diff was extremely hot after he drove it. :wink:

[bestos]

i do have both, thanks

[bestos]

i stand corrected.  I have an inch-lbs wrench, but of course it is not the dial type (which are approx 150$).  i called Randy's R&P this week about my noise that is still happening.  I told them of the winding hum that is created when i speed up and the louder intermittant hum created when i release the throttle.  They indicated to me the pinion bearing is not in the race enough.  Bearing preload needs to be higher.  So i will be installing my front locker, and cleaning the Diff. cases this saturday, in addition, i will be checking the preload with the correct instrument!  i am feeling good.  so there is the update for all you who are intersted.