Help -th400 slipping in D engages in 1&2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

rou · 11-06-2013, 09:18 PM

The drivetrain sat for about 2 years during our resto. Got her running last month and ran great but leaks at the pan. I kept adding tranny fluid until I could change the pan seal, but two days ago it stopped engaging in Drive. It did work in 1 and 2. I changed the seal/filter and refilled fluid, still same problem. Slips badly in Drive but will catch in 1 or 2. Before I go to the transmission guy tomorrow, I thought I would go to you guys for suggestions.

Thanks, Rou

**WorkinLonghorn** · 11-06-2013, 10:41 PM

Go to the transmission guy tomorrow.

I'm no expert but in my limited experience, regardless of the initial cause, once a transmission "slips badly in Drive" it is toast.

If it just isn't shifting up, then that could be an easy fix, but if the 2-3 shift results in slippage, it is done imo.

rou · 11-07-2013, 10:48 AM

Transmission guys says I have a forward shift issue. He is going to rebuild for $1000.

luvbowties · 11-15-2013, 11:59 PM

Quote:

Originally Posted by rou

Transmission guys says I have a forward shift issue. He is going to rebuild for $1000.

In our area, building a TH400 is a bit cheaper than $1000. Actually, it is one of the cheapest autos, presently used, to re-build and still have a strong, serviceable tranny.
Sam

11-06-2013, 09:18 PM	#1
rou I can see the finish line! Join Date: Apr 2010 Location: York County, Maine Posts: 88	Help -th400 slipping in D engages in 1&2 The drivetrain sat for about 2 years during our resto. Got her running last month and ran great but leaks at the pan. I kept adding tranny fluid until I could change the pan seal, but two days ago it stopped engaging in Drive. It did work in 1 and 2. I changed the seal/filter and refilled fluid, still same problem. Slips badly in Drive but will catch in 1 or 2. Before I go to the transmission guy tomorrow, I thought I would go to you guys for suggestions. Thanks, Rou __________________ 1971 C20 402BB In the process of a rebuild now Our first Build - '71 C20 LWB Last edited by rou; 11-06-2013 at 09:59 PM.

11-06-2013, 10:41 PM	#2
WorkinLonghorn Senior Member Join Date: Dec 2006 Location: Studio City, Calif. Posts: 2,855	Re: Help -th400 slipping in D engages in 1&2 Go to the transmission guy tomorrow. I'm no expert but in my limited experience, regardless of the initial cause, once a transmission "slips badly in Drive" it is toast. If it just isn't shifting up, then that could be an easy fix, but if the 2-3 shift results in slippage, it is done imo. __________________ '69 GMC C2500 Custom Camper, 8 1/2' bed, New GM 350, NP 435 Close Ratio 4spd. Trans., 3.73 Dana-60 open.Camper and Trailer wiring, PS, PB, AC, tach , three gas tanks, 2nd owner, Work-Truck supreme. Best $300 I ever spent.

11-07-2013, 10:48 AM	#3
rou I can see the finish line! Join Date: Apr 2010 Location: York County, Maine Posts: 88	Re: Help -th400 slipping in D engages in 1&2 Transmission guys says I have a forward shift issue. He is going to rebuild for $1000. __________________ 1971 C20 402BB In the process of a rebuild now Our first Build - '71 C20 LWB



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