Long story kinda. Working on a 3800 top swap going in a Montana van on the 'free parts' budget. I've got 4 4t65's sitting here, two are HD and two out of buicks basically.
#1; a HD trans I had from the '86 LeSabre L67 that migrated to the '93 SSEi and broke the input shaft. I rebuilt it with the 300m input shaft and output shaft, oil pump shaft, billet 3rd clutch piston, transgo shift kit, sonnax line pressure kit, gemini chain, and a bunch of stuff I probably don't remember... Put it in my '97 lesabre l67 winter beater, it operated in 3rd gear only, did a quick R&R with trans #2 only to find the issue was the body harness (ended up getting a donor and updating the '97 to a '99). That made trans #2 kinda work, but seeing as how it was a stupid electrical issue I put #1 back in.......
#2, was a U-pull deal from an H-body that I opened up and changed the chain, 4th hub, channel plate updated seals, and DIY shift kit. Fluid was clean and had minimal debris in the magnet, no signs of excessive wear in the pump and no odors to indicate slipping clutches. When I fixed the car's electrical problem it worked - except it would upshift funny. Not quite like going into neutral between shifts, and seemed to last about 1.5 seconds before grabbing the next gear. When it did 'decide' to upshift, the shift was firm like you would expect from a moderate shift kit.
Tonight's plan is to make sure the funky shift did not persist to rule out if trans #2 actually has an issue like I should have the day I put #1 back in. But for the life of me I can't find a reasonable explanation for that issue, regardless if it persists on the vehicle or was isolated to trans #2.
Trans #3, another HD unit that I was hoping had a bad pcs or something electrical, but I found out last night that it was definitely TCC failure and inside is a huge mess. It will end up donating the HD diff to #2 at this point.
Then I have trans #4, from the '99 buick donor that I know has 1st and reverse (donor car subframe fell out and had no brakes, didn't test drive it because I wanted the engine and interior and those were good) but based on who I got it from it never got updates like the 4th hub. Fluid is ok but you can tell it needs to be changed, so even though it doesn't stink of clutch burn I'm betting it needs a rebuild or will soon.
But anyhow, I need a working trans for my current project car, and was hoping that somebody might know what could cause the odd shifting issue (same issue for every upshift). I'm trying to avoid a complete rebuild, but don't want to toss in #4 just to have to change it again in a year or find out it's already lost 4th gear.
I know #2 works, no slipping or other issues that I noticed, aside from the shift behavior. I'm wondering if this could be caused by the gear set or ratio in the tune? Checking line pressure isn't an option when it's on the stand. At this point, I think I'm just going to bite the bullet and tear it down anyway, I want to replace the lip seal on the input clutch piston, shim the clutch packs, check the forward apply band (can't recall if I did that already), and for the peace of mind that it's going to last me at least 5 years. Hopefully the culprit for the shifting issue (assuming it's not the car it was in) is obvious.
#1; a HD trans I had from the '86 LeSabre L67 that migrated to the '93 SSEi and broke the input shaft. I rebuilt it with the 300m input shaft and output shaft, oil pump shaft, billet 3rd clutch piston, transgo shift kit, sonnax line pressure kit, gemini chain, and a bunch of stuff I probably don't remember... Put it in my '97 lesabre l67 winter beater, it operated in 3rd gear only, did a quick R&R with trans #2 only to find the issue was the body harness (ended up getting a donor and updating the '97 to a '99). That made trans #2 kinda work, but seeing as how it was a stupid electrical issue I put #1 back in.......
#2, was a U-pull deal from an H-body that I opened up and changed the chain, 4th hub, channel plate updated seals, and DIY shift kit. Fluid was clean and had minimal debris in the magnet, no signs of excessive wear in the pump and no odors to indicate slipping clutches. When I fixed the car's electrical problem it worked - except it would upshift funny. Not quite like going into neutral between shifts, and seemed to last about 1.5 seconds before grabbing the next gear. When it did 'decide' to upshift, the shift was firm like you would expect from a moderate shift kit.
Tonight's plan is to make sure the funky shift did not persist to rule out if trans #2 actually has an issue like I should have the day I put #1 back in. But for the life of me I can't find a reasonable explanation for that issue, regardless if it persists on the vehicle or was isolated to trans #2.
Trans #3, another HD unit that I was hoping had a bad pcs or something electrical, but I found out last night that it was definitely TCC failure and inside is a huge mess. It will end up donating the HD diff to #2 at this point.
Then I have trans #4, from the '99 buick donor that I know has 1st and reverse (donor car subframe fell out and had no brakes, didn't test drive it because I wanted the engine and interior and those were good) but based on who I got it from it never got updates like the 4th hub. Fluid is ok but you can tell it needs to be changed, so even though it doesn't stink of clutch burn I'm betting it needs a rebuild or will soon.
But anyhow, I need a working trans for my current project car, and was hoping that somebody might know what could cause the odd shifting issue (same issue for every upshift). I'm trying to avoid a complete rebuild, but don't want to toss in #4 just to have to change it again in a year or find out it's already lost 4th gear.
I know #2 works, no slipping or other issues that I noticed, aside from the shift behavior. I'm wondering if this could be caused by the gear set or ratio in the tune? Checking line pressure isn't an option when it's on the stand. At this point, I think I'm just going to bite the bullet and tear it down anyway, I want to replace the lip seal on the input clutch piston, shim the clutch packs, check the forward apply band (can't recall if I did that already), and for the peace of mind that it's going to last me at least 5 years. Hopefully the culprit for the shifting issue (assuming it's not the car it was in) is obvious.
