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Overdrive kicks in?...

DieselSlug

DieselSlug

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Well, havent been driving my truck for a while now but i have been pondering this question for a while. My overdrive doesnt kick in until 54mph. Is this correct?? I hate it, because any lower than 54 and im cruising at about 2500 rpm. I feel like im suckin the fuel down. When does everyone elses engage? I hate getting stuck behind a car that is doin 52 and it will not shift into OD until i get to 54. It feels as if it "should" shift into OD at 50 (to me). The truck has 3.42 gears. I am planning on getting a gl4 for the new engine. Will the gl4 lower the mph where the tranny shifts into OD? It feels like it doesnt have any power when the r's are turning like that, i feel like i could go better in OD. Any insight would be appreciated!!!
 
Im thinking 45mph for me with 4.10s, but to tell you the truth Im not positve as all I know its done it the same way for years :eek:
 
I think he means Tcc lock up......I lock up at 43 mph weather in 3 or OD.


53 mph seems a bit high......FWIW is your speedo accurate, I believe TCC lock up is controlled by PCM anyway.
 
TCC lockup for my truck is ~48 mph.

DS, you've got a 94, so you can put the TCC lockup switch in.
 
My OD engages before 30 mph, it was that way with stock pcm and with Wester's chip

Leo
 
Mine engages at 45 stock. 4.10's. Too late for me too. I wish it engaged around 40. It is controlled by the pcm for sure, so a reflash will help that.

Also, it controls shifting pressure? I notice when I shift into OD under 1900 RPM I feel it 'shutter'? Almost like it needs more shift pressure me thinks.
 
I got to get that gl4 then. I feel like im using so much fuel at anything below 55, i almost try to keep it at 55 all the time for fuel purposes....
 
mine used to kick in at 35mph then the tranny went and the rebuilt unit kicked in at 45mph and i asked the shop about it and they went for a test ride with me and they said it was operating quite normally. then went with heaths hp4 and still kicks in at 45mph. big difference is it will stay in lockup longer b4 downshifting. I like it. Ed
 
Under moderate to light throttle the tranny will shift into 4th (OD) at about 35 mph then at near or around 45 mph the TCC locks and the RPM will drop about 300-400

Now if the VSSB has been tweeked to allow for larger tires, things may be skewed slightly.

The taller geared trucks will shift to lockup a tad later to allow the engine to run in the "sweet spot"

The rigs with 4.10 butt gears do lock at around 45 MPH. This is very normal.
A rig with 3.42's will for sure lock later due to the lower RPM vs road speed.

I don't think you have a serious problem here but more likely its normal for the rig.

Try this test...

Drive the rig on a level road in the OD position.

Once you reach about 45 or so, pull the shifter to the D or 3rd position and see if the RPM raises some.

If the RPM pops up the tranny is indeed shifting to 4th (OD)
The last shift is the TCC (yours at 54)
Once in lockup a slight pressure on the throttle will not bring about any rise in RPM until the vehicle speed increases as the TCC is locked and there is no slippage in the converter.

MGW
 
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So there is no way to get the tcc to lockup any quicker? It just feels useless with the r's that high. I will test the truck when i get the rest of the parts for the starting system. Thanks fo rthe insight, so i guess my question is about tcc lockup....
 
Were going to have to wait, because im not buying the gl4 till the new engine is installed, due to the stupid head b/s...
 
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