4l60e downshift
Thread Starter
Registered User
Joined: May 2018
Posts: 4
Likes: 0
4l60e downshift picked up an Lt1 with the A4 and 190k on the clock. Its seems to me as the transmission is not downshifting as low as it should be. In OD at around 50 mph it just down shifts once and doesn’t seem to get into the powerband. Is there a down shift cable that could be adjusted or am I stuck with this till I rebuild the trans and install a shift kit?
TECH Junkie
Joined: Nov 2013
Posts: 3,913
Likes: 366
From: White Bear, Mn
If you have 2.73 gears 1st will run you out to about 55 mph meaning if you are in 4th it is not going to downshift to 1st.
So what you are stuck with is downshifting to the very bottom of 2nd "turd gear" lol
Drive about 35mph in 4th and lay into it and it should hit 1st. 2.73's (if that's what you have) kind of suck unless you're going like 85 mph because 2nd runs you out to about 95-98 mph
So what you are stuck with is downshifting to the very bottom of 2nd "turd gear" lol
Drive about 35mph in 4th and lay into it and it should hit 1st. 2.73's (if that's what you have) kind of suck unless you're going like 85 mph because 2nd runs you out to about 95-98 mph
picked up an Lt1 with the A4 and 190k on the clock. Its seems to me as the transmission is not downshifting as low as it should be. In OD at around 50 mph it just down shifts once and doesn’t seem to get into the powerband. Is there a down shift cable that could be adjusted or am I stuck with this till I rebuild the trans and install a shift kit?
1994/1995 up are 100% computer controlled.
Thread Starter
Registered User
Joined: May 2018
Posts: 4
Likes: 0
Ok sorry, it’s a 95 so it’s computer controlled. I’ll run that mph test tomorrow heading into post. Any gear combo make it better? Rear end needs to be rebuilt any way mad whine from botched 3.73 install.
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
With a 190k 95 4l60e you have to be concerned with the overall health of the transmission. GM didn't really start to get these units right until 96 and up. Perhaps, as stated above, what you're experiencing may be a rear end ratio factor. But you have to be thinking about the performance of the transmission in general - shift quality as well as shift timing, is there slippage, failure to engage gears, etc.
Joined: Nov 2001
Posts: 34,605
Likes: 2,509
From: Schiller Park, ILL Member: #317
But, it's possible that it is downshifting correctly and you're just experiencing the "dead spot" mentioned above. The best way to test this would be to manually put the selector in 3rd gear (D, not OD) at that speed and then go WOT, seeing if you get an additional downshift to 2nd gear and/or if it seems to pull any harder. This will give you a better indication of what's actually happening, and a comparison to what you might or might not be feeling when you do this from OD.
Someone may have installed a shift kit at some point then.
Trending Topics
It needs to be reprogrammed for the gear change. He said he put 3.73's in it, now the driveshaft rpm is higher compared to mph. upshifts and downshifts are controlled by mph and tps. The speedo would also be off, reading higher than vehicle speed.
Joined: Nov 2001
Posts: 34,605
Likes: 2,509
From: Schiller Park, ILL Member: #317
It actually does matter.
It needs to be reprogrammed for the gear change. He said he put 3.73's in it, now the driveshaft rpm is higher compared to mph. upshifts and downshifts are controlled by mph and tps. The speedo would also be off, reading higher than vehicle speed.
It needs to be reprogrammed for the gear change. He said he put 3.73's in it, now the driveshaft rpm is higher compared to mph. upshifts and downshifts are controlled by mph and tps. The speedo would also be off, reading higher than vehicle speed.
From personal experience if the speedo hasn't been corrected for the gear change all the factory shift points will be fine where they are. The mph and rpm as far as the computer is concerned is still doing the same thing and matching up just the way it did before. If someone did try to correct the speedo and didn't fully go through tuning the tranny and just did the minimal changes to get part throttle decent then said the hell with the rest could be the problem.
From personal experience if the speedo hasn't been corrected for the gear change all the factory shift points will be fine where they are. The mph and rpm as far as the computer is concerned is still doing the same thing and matching up just the way it did before. If someone did try to correct the speedo and didn't fully go through tuning the tranny and just did the minimal changes to get part throttle decent then said the hell with the rest could be the problem.
You're right, the speedo will read exactly the same at any given rpm. The only problem is, the car isn't going that speed.
The computer shifts off mph which is calculated off the driveshaft (more specifically the output shaft. You swap from 2.73 to 3.73 your driveshaft is now going faster at every actual mph. At 60 mph with 25" tires and 2.73's in .7 overdrive the driveshaft rpm is 2201. With 3.73's it's 3007. Just with that gear swap it goes from being calibrated to 60mph in the example above to 81 mph.
It only seems the same because the speedo vs tach readings are the same.
I'll leave it at that. Kind of tired of wasting my time. It's fact not hearsay. It's not my opinion.