what the hell is wrong with 4th gear?!?! is this "slipp

[Dan RareGP]

ok, im kinda green with tranny problems as Ive never had any before but the car shifts fine in all gears and the tourqe converter locks up in third.

however when im on the highway im in OD at like 3000rpm and If I give the car any gas the revs shoot up to over 4000rpm before I start making anymore power again and then its still not transfering the power correctly. I think this is "slipping" but not sure. If im in D3 I dont get the problem as 4th is locked out. Dunno whats going on here. Had the tranny flushed and filled today and the shifts on 1,2,3 cleaned up nicely but 4th still has this issue. Fluid looked good and no metal on the magnet as I asked to see it. Can I just drive around in D as opposed to OD to prolong life as I hate to see my valvetrain taching out at over 4k on the highway for long periods of time. Is my tranny gonna die? or am I just never gonna get full use of 4th gear? I added the Lucas magic oil stuff today too. whats going on? burnt clutch pack or whatever? what does it take to fix it short of a full rebuild?

 

 

Car is a 1990 Turbo grand prix with 130,000 miles and 40,000+ miles on a rebuilt tranny.

 

 

minor correction, it still occasionally shifts late going into third gear, but rare and not very severe. all other shifts are good if not great.

 

Thanks

Dan

[Robby1870]

the 4th gear clutch on the 4T60 is very weak. It sounds like your slippin and that the 4th gear clutch has gone you. Do you do a lot of top speed runs? These will cause that 4th gear clutch to wear premamturely. yeah you can drive around in D3 to avoid 4th gear. Thats what I would do. You will just have to live with 3rd with th TC locked up in the highway. Hope you can get her fixed. Im sure others will have opinions, wait on them

 

But get that fixed ASAP like Rob said cuz you'll turn like 3000 around 65 or 70mph.

 

Robby

[ismellrealbad]

have fun killing your gas twice as fast leaving it in 3rd. get that fixed asap

[Dan RareGP]

got a quote today from a reputable rebuilder for about $1300.

 

 

they only do full rebuilds using OEM parts. Anything I need to communicate to them before the rebuild occurs such as any packets of info by Jeff M floating around?

 

what if I dont decide to rebuilt it until say I get out of school for the semester in may? It drives now and shifts high and obviously sucks on the highway but I can live with it until then. How long will the tranny last like this? will it completly die out and shit on me at the wrong time? I want to either get this done next week or wait until summer. also are partial rebuilds possible and or worth it? the shop will only do full rebuilds.

 

 

also how bad is 3000rpm on the highway, seems like thats my normal RPM now in any gear. I cant imagine its too good for the valvetrain but I dont remember what the TGP usually tachs at on the road or highway. mileage has alwasy been 19-20mpg, but im down to 17mpg now.

 

will driving in fourth with it slipping destroy it faster than driving in third at a slightly higher rpm?

 

fawk, better get this beast in next week. put it on the charge I guess :x

 

thanks,

Dan

[Robby1870]

yeah take it in ASAP. If one of your gears has gone south on you, more might do the same, and you dont have anyway of knowing when. I dont think a partial rebiuld would be worth it. I mean, if you got the whole thing apart, why not rebuild the whole thing. However, a new 4T60 tranny is around $1100. I know the 4T60 in the TGP is beefier than say mine with my 3.1L but, a new one shouldnt that much more than one for a N/A car. If you can put a tranny in yourself, buy a new one, if it is cheaper, and istall it yourself. If not, get the full rebiuld. You dont need to cut corners with trannys especially not with front wheel drive ones and ones mated to truboed motors. My 3.1L will turn about 2000rpms in overdrive at 70 mph and get 30 MPG on the highway. You should get the tranny rebuilt.

 

Robby