1999 S-80 T6 Transmission shudder

SimLyons · Post by **SimLyons** » 23 Feb 2014, 19:27

I've completely flushed my trans. (the infamous one we all hate), new filter etc. I bought the car last October and know its history very well. The original trans. was replaced about 60K miles ago. Generally the trans is fine. I go easy on it in 1st and 2nd. I've noticed a "shudder" or "judder/short stutter" between 2nd and 3rd and 3rd-4th. It's pretty low key now and my wife doesn't notice. I do and am concerned that this might be early stages of failure. Any ideas? Suggestions? Thanks all!

James1 · Post by **James1** » 24 Feb 2014, 21:41

I started having that problem with my 99 S80 and I started pushing the W button every time I started the car and problem does not happen . Hope this helps you also.

SimLyons · Post by **SimLyons** » 28 Feb 2014, 22:02

I generally don't use additives. But, 2 days ago I added 20 oz of Lucas Transmission Conditioner to my transmision. Have driven 60 miles and all the "shuddering" during shifts is gone. It shifts like a perfect transmission. I'm crossing my fingers that this will keep it up.

midimykeys · Post by **midimykeys** » 17 Mar 2014, 02:55

Sim ~ how did the Lucas work, have you noticed anything or is the problem seemingly gone? I have the exact same problem with my 2001 2.9 n/a, and would love to know how you fared.

majorcode · Post by **majorcode** » 17 Mar 2014, 09:01

Hi, when I flushed my transmission I felt the same and used LUCAS which gave good results. But I strongly suggest at least drive a up to 1000 KM before using Lucas and while driving with in 1000 KM ....drive gently rather giving extra RPM. Hope fully you might not need Lucas and keep the additive away until really needed.

Cheers!

SimLyons · Post by **SimLyons** » 17 Mar 2014, 17:30

Thanks for the advice! I've already got the Lucas in the trans with all new fluid. When I get 500+ miles on it I'll do another drain and fill and see how it responds. If needed I'll add another container of Lucas. This is a fabulous car in all other respects (well, almost!).

midimykeys · Post by **midimykeys** » 18 Mar 2014, 08:07

ok, thanks for the info. I have read however that the transmission should never be flushed, but drained and filled slowly in increments. There have been horror stories about the flushing process jostling up loose gunk in the transmission and ultimately ruining it. Which would be better to do?

SimLyons · Post by **SimLyons** » 18 Mar 2014, 21:54

If I was to do it over, I'd do the use the slower drain and fill, doing it every oil change initially. When it's all done with clean fluid, move back to about every 30K miles. Keep that on a permanent schedule.... that should work. For me an advantage of dropping the pan, draining all of it out and cleaning all the ultra fine metal layering on the pan (it will be there!) and clean the magnet, install a new filter, (get decent kit) and gasket I just feel I've done a good job.

If you take on the job, be certain everything is very, very clean before putting it all back together (IF you flush).

You asked if I notice the difference with the Lucas. I do. It is an improved shift, but too early to make a real opinion. You have a NA engine and that shouldn't be hurtng (trans). You have reasonable torque, whereas the T-6 is way overtorgued and in 1st and somewhat 2nd gears it's just too much for that trans.

Sim

midimykeys · Post by **midimykeys** » 19 Mar 2014, 12:51

I'm going to pickup a 24oz bottle of Lucas transmission conditioner tomorrow and give it a shot. I'm wondering if I can just add the whole bottle to existing transmission fluid, or do I need to drain some fluid out first, or do a drain and fill while adding the Lucas? Sorry, I've never messed with transmissions before (850's never needed anything!) Thanks.

midimykeys · Post by **midimykeys** » 19 Mar 2014, 13:07

I called AAMCO and told them the symptom, and they recommended a drain and fill with a shudder stop additive. Instant shudder fixx? Now I'm torn.