Transmission (TH350) Problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

gbkwork · 05-12-2003, 01:54 PM

This site has been a huge help in the past so when my transmission intermittently stopped engaging I thought I would give all of you a shot at it.

Here's the problem:

When I shift from park into any drive gear (including reverse) no power gets to the wheels...the engine just revs. I have checked the linkage and it appears to be operating OK outside of the case.

I plan on upgrading the tranny at some point in the future for towing purposes and the future installation of a built engine, but I did not intend on doing this right now. If anyone knows of a quick fix I would appreciate it.

Thanks

**COBALT** · 05-12-2003, 02:13 PM

Check the fluid. This always happens when the valve body isn't getting enough fluid pressure to change the fluid direction in the valve body to apply the pin for reverse, or engage the clutch packs for 1.

You say it happens every once in a while? How long do you let it sit in gear when this happens? Don't be imatient. Next time it happens let it sit there and time it with a stop watch. See if the length of time it takes to finally pop into gear gets longer and longer. If it does your clutch plates and apply band are shot.

What's the fluid look like?

jku72 · 05-12-2003, 02:19 PM

If its just slow in engaging, but does eventually, it sure is a sign of low pressure. What causes low pressure? Dirty filters, low fluid levels, or leaks. It could be the pump is going away, but my money is on fluid level first, dirty filter second.

05-12-2003, 01:54 PM	#1
gbkwork Registered User Join Date: Oct 2002 Location: Chico, CA Posts: 39	Transmission (TH350) Problem This site has been a huge help in the past so when my transmission intermittently stopped engaging I thought I would give all of you a shot at it. Here's the problem: When I shift from park into any drive gear (including reverse) no power gets to the wheels...the engine just revs. I have checked the linkage and it appears to be operating OK outside of the case. I plan on upgrading the tranny at some point in the future for towing purposes and the future installation of a built engine, but I did not intend on doing this right now. If anyone knows of a quick fix I would appreciate it. Thanks __________________ '72 Custom LWB 383 ci, Lunati 213 / 219 cam (60101L), 2.02/1.6 heads, Crane roller rockers, HPC coated ramhorns, FIRST TPI, '90 Corvette ECM, , Built 700R4, 3.73 Eaton Posi 12-bolt, Magnaflow dual exhaust, PW, Keyless DL, ECE Hidden Hitch, New chrome all around, 17" Torq Thrust II's, 255/50 & 275/50 Nittos, ART airbags, Rick's custom tank w/ custom in-bed filler, '02 Silverado seats, Rod Doors headliner / A-pillar covers and door panels.

05-12-2003, 02:13 PM	#2
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	Check the fluid. This always happens when the valve body isn't getting enough fluid pressure to change the fluid direction in the valve body to apply the pin for reverse, or engage the clutch packs for 1. You say it happens every once in a while? How long do you let it sit in gear when this happens? Don't be imatient. Next time it happens let it sit there and time it with a stop watch. See if the length of time it takes to finally pop into gear gets longer and longer. If it does your clutch plates and apply band are shot. What's the fluid look like? __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

05-12-2003, 02:19 PM	#3
jku72 Registered User Join Date: Jan 2002 Location: cornville, maine Posts: 659	If its just slow in engaging, but does eventually, it sure is a sign of low pressure. What causes low pressure? Dirty filters, low fluid levels, or leaks. It could be the pump is going away, but my money is on fluid level first, dirty filter second. __________________ jku Cornville, Maine 68 C10 burb 42 Willys MB 46 Dodge WF-32 1.5 ton 53 & 56 Olds' 60 Cadillac 22 Dodge Brothers

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