Syclone hard shifting transmission

rgsycl

New member
Is it normal for the transmission to shift hard on these trucks? Seems much harder than my S10. My mechanic asked me if the truck had a shift kit on it but I don’t know what the prior owner may have done etc, but he never mentioned that and the service records don’t indicate that. My syclone is a low mileage example and tranny fluid was replaced 2 years ago as part of ongoing maintenance. The truck always seemed to shift hard but lately it seems more noticeable.
 

Bo Cee

New member
Is it normal for the transmission to shift hard on these trucks? Seems much harder than my S10. My mechanic asked me if the truck had a shift kit on it but I don’t know what the prior owner may have done etc, but he never mentioned that and the service records don’t indicate that. My syclone is a low mileage example and tranny fluid was replaced 2 years ago as part of ongoing maintenance. The truck always seemed to shift hard but lately it seems more noticeable.
Hi. I just bought a Sy and the shift from 1st to 2nd was jarring to say the least. The mechanic fixing my truck pointed to the cables on the front of the throttle body and said he just adjusted them and in no time it's a normal shift again. Sorry, can't get more technical than that but I thought I was going to have to rebuild the tranny and it's day and night. Hope this helps.
 

rgsycl

New member
Hi. I just bought a Sy and the shift from 1st to 2nd was jarring to say the least. The mechanic fixing my truck pointed to the cables on the front of the throttle body and said he just adjusted them and in no time it's a normal shift again. Sorry, can't get more technical than that but I thought I was going to have to rebuild the tranny and it's day and night. Hope this helps.
Thanks.... I am not a mechanic and did not realize the throttle body was related to the tranny, I thought the throttle body only regulated air going into the manifold. I’ll have him look at those cables for sure. My hard shift is primarily 1st and 2nd also.
 

Goodgollyjosh

Active member
The 1-2 shift is one of the things that is different about these transmissions compared to other 700r4's. They modified the valve body on the Sy/Ty from the factory. I don't recall mine ever being particularly rough on the 1-2 shift, but mine had been modified. Maybe one of the other forum members with more knowledge on the subject can chime in.
 

DaveP's Ghost

Active member
Do not adjust the Throttle Valve cable in an attempt to change shift quality or timing. You can F-up your transmission.

The TV system in the 4L60 (in 1990, the transmission became the 4L60, it was no longer a "700R4") is critical to establishing the correct pressure at the correct throttle setting. It is not a "kick down cable". It is not a "shift adjustment". It controls Line Pressure based on specific throttle opening. If pressure is low, clutches can slip and burn. This transmission has been around for 40 years, and there are still people that don't understand the importance of the TV system. Like the "mechanic" that adjusted the cable to adjust "shift quality".

The really easy way to know if your TV cable setting is correct: Shifter in D4. Leave at light throttle from a dead stop. Let the trans upshift into 2nd. As soon as it shifts, NAIL IT, all the way to the floor. The transmission MUST downshift back into 1st gear. If it does not, the TV cable is not adjusted correctly. FIX IT!

The LHM SyTy transmission has a really harsh 1-2 shift. It's a character of the SyTy.
 

Goodgollyjosh

Active member
I think the factory cables are pretty high quality. I replaced mine for good measure when the trans was out with the only one that I could find available, which was from Sports Machines. It is a reproduction unit, and I did not find the quality to be that great. I'd stick with the OEM cable, unless it is absolutely stretched too far to get the piano wire tight adjustment.
 

thesyguy

Member
Do not adjust the Throttle Valve cable in an attempt to change shift quality or timing. You can F-up your transmission.

The TV system in the 4L60 (in 1990, the transmission became the 4L60, it was no longer a "700R4") is critical to establishing the correct pressure at the correct throttle setting. It is not a "kick down cable". It is not a "shift adjustment". It controls Line Pressure based on specific throttle opening. If pressure is low, clutches can slip and burn. This transmission has been around for 40 years, and there are still people that don't understand the importance of the TV system. Like the "mechanic" that adjusted the cable to adjust "shift quality".

The really easy way to know if your TV cable setting is correct: Shifter in D4. Leave at light throttle from a dead stop. Let the trans upshift into 2nd. As soon as it shifts, NAIL IT, all the way to the floor. The transmission MUST downshift back into 1st gear. If it does not, the TV cable is not adjusted correctly. FIX IT!

The LHM SyTy transmission has a really harsh 1-2 shift. It's a character of the SyTy.
This is spot on. DO NOT ADJUST THE TV CABLE TO SOFTEN THE SHIFT! It will lead to transmission failure. My tranny shifts hard 1-2 and has since day one. 135k on the stock original transmission and it still shifts hard. Fluid and filter changes only.
 
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