PontiacBonnevilleClub.com

Car: 1995 Pontiac Bonneville SE

Okay, sorry if this has come up before... I've always a somewhat of quick thud of a sound/feeling when my bonne shifts to 2nd. Now after two years, it seems to do that in all gear changes up and down. A mechanic off the street told me to get a new trans modulator, "will shift like butter" he says. Well I did (bad idea), now she shifts like I'm racing in Nascar (Slight whiplash feeling).

So... I have never changed the fluid. Bought with 36k miles, now has 53k miles. Fluid is a little redish-brown / smells slightly burnt (really not to bad).

I'm pretty worried. I don't really want to drive it now (putting back the older modulator in this weekend).

If I change the fluid, would I likely get back my shift smoothness? or should I prepare for the worst?

First off, burnt fluid is not going to help anything, you may wish to put changing that pretty far up on the todo list. Also, the new modulator you got, is it an adjustable unit? If it is, you will notice an adjustment screw, usually inside the tube where the vacuum line goes. You can back that off until you get the shifting you like. I did the very same thing, except I tightened mine down, because I don't want shifts "like butter". As far as preparing for the worst, I will let the experts make that call.

Change your fluid. It's ~15-16 years old and very degraded. Then report back to us how it shifts.

BTW, a $7 hand pump will make changing the ATF much less messy.

Dave, that pump from wal-mart absolutely sucks after about 3 quarts, lol. Next time I'm getting the bottle pump from Amsoil.

Ed, my hand pump was from Harbor Freight. It's been used twice now. It's not had a problem getting all 6 quarts out of the pan. The trick is to keep going when it starts sucking some air. You'll hear it suck air, then suck mostly air. You're done when it sucks mostly air.

These little hand pumps are very hit-or-miss. Some are good, others aren't. They're still handy to ave around for these occasions, IMO.

Mounts?

LeSabre in Buffalo wrote:Change your fluid. It's ~15-16 years old and very degraded. Then report back to us how it shifts.

BTW, a $7 hand pump will make changing the ATF much less messy.

I might check that out. Walmart you say? Okay, will try next couple of days.

repinS wrote:Mounts?

I don't think it's the mounts. It doesn't really bang super hard. Nothing like metal on metal; and they still look intact.

RJolly87 wrote:First off, burnt fluid is not going to help anything, you may wish to put changing that pretty far up on the todo list. Also, the new modulator you got, is it an adjustable unit? If it is, you will notice an adjustment screw, usually inside the tube where the vacuum line goes. You can back that off until you get the shifting you like. I did the very same thing, except I tightened mine down, because I don't want shifts "like butter". As far as preparing for the worst, I will let the experts make that call.

I'm going to try that right now! I believe it was a adjustable one, but didn't see anything to adjust (nothing on box or piece of paper it came with either).

Update: Just adjusted it (Thanks RJolly87), now going to Walmart for that pump, lol. I will update in a couple days.

If you happen across Valvoline MaxLife ATF, get that. It's very good fluid, and only a few dollars more for a gallon than SuperTech Dex/Merc.

Okay, got pump at Walmart ($8.50)

Checked fluid and seemed to be overfilled

Pumped out about 3.5 quarts - then, put in one quart of Valvoline MaxLife ATF. Started her up and let her run for 5 minutes (Still was already hot when pumping).

Checked level and was dead on with dip stick leveling.

With adjusting the modulator, putting in a new quart and made sure it had the right level, she's back to her old self again Shifts smooth, and shift at more optimum rpm ranges.

I am going to change the fluid though, I will pump it again next week and buy more Valvoline MaxLife ATF to replace.

-Thanks for all the help everyone

LeSabre in Buffalo wrote:Change your fluid. It's ~15-16 years old and very degraded. Then report back to us how it shifts.

BTW, a $7 hand pump will make changing the ATF much less messy.

That pump worked out great! (almost 9 bucks over here after taxes) Good thing I bought it too because I was 2 quarts overfilled.

Thanks a bunch!

Glad to hear the pump worked for you! And keep us posted on what develops!