Backlash in the Transaxle? - Page 11 - 3000GT/Stealth International Message Center

DoctorDex · 03-15-2007, 06:35 PM

I think I'm going to look into adjusting my rear dif using Jeff's procedure outlined here: Adjusted Rear Diff Backlash, some hints

It seems to have worked for him.

AudioPmp23 · 03-15-2007, 06:57 PM

Yep, definitely some good read to go along with the service manual. I'll report when I get her driving again. Im not so sure this one fixed my issue though...

DoctorDex · 04-01-2007, 09:50 PM

Checked my carrier bearings the other day. My rear carrier is shot. Rough guesstimate of rear play = 1 - 2 inches, whereas front is only a 1/2 inch or so.

I've ordered new bearings and I'm hoping to get them installed in the next few weeks. Praying this will help fix my clunk as its gotten to the point its unbearable and I'm embarrased to give people a ride.

AudioPmp23: How are you making out?

AudioPmp23 · 04-02-2007, 10:36 AM

Hey sorry man for not reporting back. Drivetrain clunk is definitely not solved but I think it's a little better. Most noticeable in second gear. I know whatever my problem is, it lies in the transmission and I dont want to tear that thing down again for quite some time. My rough guess would have to be the VCU but at $3000 that thing can clunk all it wants...

EDIT: Dude, try the zip tie fix for the C.B., that shit does work for C.B. play. Mine have held for 3 months so far. Plus a bag of big zip ties is like 6 bucks at Depot..

DoctorDex · 04-02-2007, 12:57 PM

$3000?? I bought a new VCU and planetary gear (it came free with the VCU) for $475. I installed it, when I changed my output shaft, with the transaxle still in the car. However, this did nothing to fix my clunk. If you really want, I'm sure you can find a used one. However, I doubt it'll fix your clunk.

So are you able to measure backlash at your differential with the car in gear?

I'm now of the opinion that the majority of my backlash is coming from the driveshaft back. Either bad carriers, rotted out rear section of the driveshaft or play between the spider gears. Hoping to get at 'er in the next few weeks to finally fix this problem.

AudioPmp23 · 04-02-2007, 05:39 PM

Yeah I might try and "solve" this problem by process of elimination and wishful thinking. I want to buy a CFDS either way so I'll hope that will at least help by reducing the weight going back to the rear diff. If that doesnt work and I win Powerball, I'll order a new tranny....

DoctorDex · 06-17-2007, 12:33 AM

Back from the dead...

I finally got the chance to try and tackle this driveline issue; I was planning on installing new carrier bearings, but before doing so I decided to make some proper measurements with a dial indicator.

Backlash between the driveshaft & rear dif:
Car in neutral: 1 inch
Car in Reverse: 0.620 inches
Car in 1st to 5th: 0.810 - 1 inch

After making these measurements I concluded that installing new carriers is going to be a waste of my time. These measurements are clearly out of spec and it is clear the backlash is indeed coming from the transaxle.

wraith · 06-17-2007, 08:16 AM

Why do you think its backlash causing the clunk? When your moving and applying power, the driveshaft can move up and down also at the joints, the rear diff can tilt if its got worn supports, the motor mounts could be worn out allowing the whole transaxle to tip and turn which could also make the driveshaft wobble. You see, the reason I say this is that your talking MM of backlash and having measured my back lash at the diff housing versus the companion flange, I have about 0.5 inches of play turning from one side to another and my car only clunks when I take up the slack in first gear at a light. However, I have owned my car forever, and its done that since it had 30k miles and still does the same thing at 126k miles. My POntiac GTO has a multi-link driveshaft also, and it never made a sound when it was brand new but 10k miles down the line, I started hearing a clunk but again only on initial driveline take-up off the line or moving while off the clutch and back on. Neither car clunks or vibrates once its in gear and accelerating. The VR-4 will occasionally (if my tune is a little off in first gear) surge in 1st and the car will jerk but it did that when I had a small vacuum leak and the car was BPU about 6 years ago. I have since fixed the surge thru tuning and that jerk is gone now.
I think you should get the car up on a lift and have some one get it in gear and try different things like pull the parking brake and give it a little clutch to see if anything tilts or moves in a way that shows where a bushing or a bolt is missing or loose.
When my car was new, the guys at MItsu had it up on the rack to check the VCU and they put it in gear and let it run in idle and the wheels would not turn smooth but with a jerky clunky movement (rythemically with the drivetrain slop), and they said that was normal. The cars just got alot of slop when you add up all the joints and components.

DoctorDex · 06-17-2007, 09:26 AM

An inch of backlash measured at the rear dif with in neutral with the ebrake on seems a bit much to me? Could this be backlash between the crown and pinion? If it is, how come I can measure similar amounts of backlash with the car in gear?

My car clunks in all gears. Its especially annoying at low speeds @ low rpm because it'll start to clunk back and forth rhytmically until I put my foot on the clutch or take up the slack (a much bigger clunk). When shifting between gears it clunks, so much so it feels as though the transfer case is going to split in two. To get around this, I have to slip the clutch in all gears and I'm assuming this is the cause of my premature clutch wear....

wraith · 06-17-2007, 07:35 PM

Quote:

Originally Posted by DoctorDex

An inch of backlash measured at the rear dif with in neutral with the ebrake on seems a bit much to me? Could this be backlash between the crown and pinion? If it is, how come I can measure similar amounts of backlash with the car in gear?

My car clunks in all gears. Its especially annoying at low speeds @ low rpm because it'll start to clunk back and forth rhytmically until I put my foot on the clutch or take up the slack (a much bigger clunk). When shifting between gears it clunks, so much so it feels as though the transfer case is going to split in two. To get around this, I have to slip the clutch in all gears and I'm assuming this is the cause of my premature clutch wear....

Yah well, that is pretty bad, and one inch of back lash is terrible out of spec

03-15-2007, 06:35 PM	#101 (permalink)
DoctorDex Forum Member Join Date: Jul 2005 Location: Edmonton, AB Drives: '91 VR4 - RIP Trader Rating: (14)	Re: Backlash in the Transaxle? I think I'm going to look into adjusting my rear dif using Jeff's procedure outlined here: Adjusted Rear Diff Backlash, some hints It seems to have worked for him. __________________ '91 VR4 - Modlist: DR650R turbos, Snow stage 2D alky kit, DSM SMICs, blowthrough ported LT1 MAS, Dejon Tool intakes & y-pipe, Blitz DSBC Spec R, HKS SSQV BOV, PTE 580cc injectors, Dual feed fuel system with Aeromotive FPR & filter, Hotwired Supra pump, HKS DLI, MSD Wires, Apex'i S-AFC II, MAFTranslator, Turbobob ECU, Scanmaster III, LC-1 WBO2, ESP downpipe, Vac/EGR delete, Gutted precats and test pipe, Maximal solid mounts, 300m 18 spline output shaft, Centerforce Dual Friction clutch, RPS flywheel, GC coilover conversions with helper springs, Powerslot slotted rotors, Goodridge SS brake lines, Hawk pads (front), Stillen metal matrix pads (rear)

03-15-2007, 06:57 PM	#102 (permalink)
AudioPmp23 Getrag Wrestler Join Date: Aug 2003 Location: Lakewood CO Drives: Pearl White 93 VR-4 Trader Rating: (3)	Re: Backlash in the Transaxle? Yep, definitely some good read to go along with the service manual. I'll report when I get her driving again. Im not so sure this one fixed my issue though... __________________ Hi my name's Nate and I've been addicted to boost for four years now...

04-01-2007, 09:50 PM	#103 (permalink)
DoctorDex Forum Member Join Date: Jul 2005 Location: Edmonton, AB Drives: '91 VR4 - RIP Trader Rating: (14)	Re: Backlash in the Transaxle? Checked my carrier bearings the other day. My rear carrier is shot. Rough guesstimate of rear play = 1 - 2 inches, whereas front is only a 1/2 inch or so. I've ordered new bearings and I'm hoping to get them installed in the next few weeks. Praying this will help fix my clunk as its gotten to the point its unbearable and I'm embarrased to give people a ride. AudioPmp23: How are you making out?

04-02-2007, 10:36 AM	#104 (permalink)
AudioPmp23 Getrag Wrestler Join Date: Aug 2003 Location: Lakewood CO Drives: Pearl White 93 VR-4 Trader Rating: (3)	Re: Backlash in the Transaxle? Hey sorry man for not reporting back. Drivetrain clunk is definitely not solved but I think it's a little better. Most noticeable in second gear. I know whatever my problem is, it lies in the transmission and I dont want to tear that thing down again for quite some time. My rough guess would have to be the VCU but at $3000 that thing can clunk all it wants... EDIT: Dude, try the zip tie fix for the C.B., that shit does work for C.B. play. Mine have held for 3 months so far. Plus a bag of big zip ties is like 6 bucks at Depot..

04-02-2007, 12:57 PM	#105 (permalink)
DoctorDex Forum Member Join Date: Jul 2005 Location: Edmonton, AB Drives: '91 VR4 - RIP Trader Rating: (14)	Re: Backlash in the Transaxle? $3000?? I bought a new VCU and planetary gear (it came free with the VCU) for $475. I installed it, when I changed my output shaft, with the transaxle still in the car. However, this did nothing to fix my clunk. If you really want, I'm sure you can find a used one. However, I doubt it'll fix your clunk. So are you able to measure backlash at your differential with the car in gear? I'm now of the opinion that the majority of my backlash is coming from the driveshaft back. Either bad carriers, rotted out rear section of the driveshaft or play between the spider gears. Hoping to get at 'er in the next few weeks to finally fix this problem.

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04-02-2007, 05:39 PM	#106 (permalink)
AudioPmp23 Getrag Wrestler Join Date: Aug 2003 Location: Lakewood CO Drives: Pearl White 93 VR-4 Trader Rating: (3)	Re: Backlash in the Transaxle? Yeah I might try and "solve" this problem by process of elimination and wishful thinking. I want to buy a CFDS either way so I'll hope that will at least help by reducing the weight going back to the rear diff. If that doesnt work and I win Powerball, I'll order a new tranny....

06-17-2007, 12:33 AM	#107 (permalink)
DoctorDex Forum Member Join Date: Jul 2005 Location: Edmonton, AB Drives: '91 VR4 - RIP Trader Rating: (14)	Re: Backlash in the Transaxle? Back from the dead... I finally got the chance to try and tackle this driveline issue; I was planning on installing new carrier bearings, but before doing so I decided to make some proper measurements with a dial indicator. Backlash between the driveshaft & rear dif: Car in neutral: 1 inch Car in Reverse: 0.620 inches Car in 1st to 5th: 0.810 - 1 inch After making these measurements I concluded that installing new carriers is going to be a waste of my time. These measurements are clearly out of spec and it is clear the backlash is indeed coming from the transaxle. Last edited by DoctorDex : 06-21-2007 at 12:57 AM.

06-17-2007, 08:16 AM	#108 (permalink)
wraith resident evil Join Date: Sep 1999 Location: Oradell New Jersey Trader Rating: (15)	Re: Backlash in the Transaxle? Why do you think its backlash causing the clunk? When your moving and applying power, the driveshaft can move up and down also at the joints, the rear diff can tilt if its got worn supports, the motor mounts could be worn out allowing the whole transaxle to tip and turn which could also make the driveshaft wobble. You see, the reason I say this is that your talking MM of backlash and having measured my back lash at the diff housing versus the companion flange, I have about 0.5 inches of play turning from one side to another and my car only clunks when I take up the slack in first gear at a light. However, I have owned my car forever, and its done that since it had 30k miles and still does the same thing at 126k miles. My POntiac GTO has a multi-link driveshaft also, and it never made a sound when it was brand new but 10k miles down the line, I started hearing a clunk but again only on initial driveline take-up off the line or moving while off the clutch and back on. Neither car clunks or vibrates once its in gear and accelerating. The VR-4 will occasionally (if my tune is a little off in first gear) surge in 1st and the car will jerk but it did that when I had a small vacuum leak and the car was BPU about 6 years ago. I have since fixed the surge thru tuning and that jerk is gone now. I think you should get the car up on a lift and have some one get it in gear and try different things like pull the parking brake and give it a little clutch to see if anything tilts or moves in a way that shows where a bushing or a bolt is missing or loose. When my car was new, the guys at MItsu had it up on the rack to check the VCU and they put it in gear and let it run in idle and the wheels would not turn smooth but with a jerky clunky movement (rythemically with the drivetrain slop), and they said that was normal. The cars just got alot of slop when you add up all the joints and components.

06-17-2007, 09:26 AM	#109 (permalink)
DoctorDex Forum Member Join Date: Jul 2005 Location: Edmonton, AB Drives: '91 VR4 - RIP Trader Rating: (14)	Re: Backlash in the Transaxle? An inch of backlash measured at the rear dif with in neutral with the ebrake on seems a bit much to me? Could this be backlash between the crown and pinion? If it is, how come I can measure similar amounts of backlash with the car in gear? My car clunks in all gears. Its especially annoying at low speeds @ low rpm because it'll start to clunk back and forth rhytmically until I put my foot on the clutch or take up the slack (a much bigger clunk). When shifting between gears it clunks, so much so it feels as though the transfer case is going to split in two. To get around this, I have to slip the clutch in all gears and I'm assuming this is the cause of my premature clutch wear....